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Google LeetCode Questions

2305 questions all-time · 601 easy · 1205 medium · 499 hard
# Problem Difficulty Frequency Acceptance
1Two Sum
Array, Hash Table
Easy
100
0.6%
2Add Two Numbers
Linked List, Math, Recursion
Medium
78
0.5%
3Median of Two Sorted Arrays
Array, Binary Search, Divide and Conquer
Hard
74
0.5%
4Trapping Rain Water
Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
Hard
74
0.7%
5Longest Common Prefix
Array, String, Trie
Easy
73
0.5%
6Palindrome Number
Math
Easy
73
0.6%
7Merge Sorted Array
Array, Two Pointers, Sorting
Easy
73
0.6%
8Longest Substring Without Repeating Characters
Hash Table, String, Sliding Window
Medium
72
0.4%
93Sum
Array, Two Pointers, Sorting
Medium
72
0.4%
10Best Time to Buy and Sell Stock
Array, Dynamic Programming
Easy
72
0.6%
11Create Hello World FunctionEasy
72
0.8%
12Merge Strings Alternately
Two Pointers, String
Easy
71
0.8%
13Longest Palindromic Substring
Two Pointers, String, Dynamic Programming
Medium
70
0.4%
14Longest Consecutive Sequence
Array, Hash Table, Union-Find
Medium
69
0.5%
15Recyclable and Low Fat Products
Database
Easy
68
0.9%
16Container With Most Water
Array, Two Pointers, Greedy
Medium
68
0.6%
17Valid Parentheses
String, Stack
Easy
66
0.4%
18Majority Element
Array, Hash Table, Divide and Conquer, Sorting, Counting
Easy
66
0.7%
19Roman to Integer
Hash Table, Math, String
Easy
66
0.7%
20Merge Intervals
Array, Sorting
Medium
66
0.5%
21Number of Islands
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
66
0.6%
22Maximum Subarray
Array, Divide and Conquer, Dynamic Programming
Medium
65
0.5%
23Reverse Integer
Math
Medium
65
0.3%
24Remove Duplicates from Sorted Array
Array, Two Pointers
Easy
65
0.6%
25Subarray Sum Equals K
Array, Hash Table, Prefix Sum
Medium
65
0.5%
26Climbing Stairs
Math, Dynamic Programming, Memoization
Easy
64
0.5%
27Merge Two Sorted Lists
Linked List, Recursion
Easy
61
0.7%
28Next Permutation
Array, Two Pointers
Medium
61
0.5%
29Generate Parentheses
String, Dynamic Programming, Backtracking
Medium
61
0.8%
30Spiral Matrix
Array, Matrix, Simulation
Medium
60
0.6%
31Meeting Rooms II
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
60
0.5%
32Reverse Linked List
Linked List, Recursion
Easy
59
0.8%
33Decode String
String, Stack, Recursion
Medium
59
0.6%
34Add Two Integers
Math
Easy
59
0.9%
35Remove Element
Array, Two Pointers
Easy
58
0.6%
36Koko Eating Bananas
Array, Binary Search
Medium
58
0.5%
37Search in Rotated Sorted Array
Array, Binary Search
Medium
58
0.5%
38Move Zeroes
Array, Two Pointers
Easy
58
0.6%
39Pascal's Triangle
Array, Dynamic Programming
Easy
58
0.8%
40Minimum Number of Increments on Subarrays to Form a Target Array
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Hard
58
0.8%
41LRU Cache
Hash Table, Linked List, Design, Doubly-Linked List
Medium
58
0.5%
424Sum
Array, Two Pointers, Sorting
Medium
57
0.4%
43Single Number
Array, Bit Manipulation
Easy
57
0.8%
44N-Queens
Array, Backtracking
Hard
57
0.8%
45Largest Rectangle in Histogram
Array, Stack, Monotonic Stack
Hard
57
0.5%
46Jump Game
Array, Dynamic Programming, Greedy
Medium
57
0.4%
47Letter Combinations of a Phone Number
Hash Table, String, Backtracking
Medium
57
0.7%
48Concatenation of Array
Array, Simulation
Easy
57
0.9%
49Split Array Largest Sum
Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
Hard
57
0.6%
50Find Peak Element
Array, Binary Search
Medium
57
0.5%
51Top K Frequent Elements
Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect
Medium
57
0.7%
52Rotate Array
Array, Math, Two Pointers
Medium
56
0.5%
53Valid Anagram
Hash Table, String, Sorting
Easy
56
0.7%
54Find the Index of the First Occurrence in a String
Two Pointers, String, String Matching
Easy
56
0.5%
55House Robber
Array, Dynamic Programming
Medium
56
0.5%
56Kth Largest Element in an Array
Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
Medium
56
0.7%
57Rotate Image
Array, Math, Matrix
Medium
56
0.8%
58Group Anagrams
Array, Hash Table, String, Sorting
Medium
56
0.7%
59Search Insert Position
Array, Binary Search
Easy
55
0.5%
60Plus One
Array, Math
Easy
55
0.5%
61Viewers Turned Streamers
Database
Hard
55
0.4%
62Logger Rate Limiter
Hash Table, Design, Data Stream
Easy
54
0.8%
63Max Consecutive Ones
Array
Easy
54
0.7%
64Sort Colors
Array, Two Pointers, Sorting
Medium
54
0.7%
65Pow(x, n)
Math, Recursion
Medium
54
0.4%
66Happy Number
Hash Table, Math, Two Pointers
Easy
54
0.6%
67Sliding Window Maximum
Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
Hard
54
0.5%
68Product of Array Except Self
Array, Prefix Sum
Medium
54
0.7%
69Longest Repeating Character Replacement
Hash Table, String, Sliding Window
Medium
54
0.6%
70Single Element in a Sorted Array
Array, Binary Search
Medium
54
0.6%
71Add Binary
Math, String, Bit Manipulation, Simulation
Easy
53
0.6%
72Zigzag Conversion
String
Medium
53
0.5%
73Russian Doll Envelopes
Array, Binary Search, Dynamic Programming, Sorting
Hard
53
0.4%
74Combine Two Tables
Database
Easy
53
0.8%
75Longest Increasing Subsequence
Array, Binary Search, Dynamic Programming
Medium
53
0.6%
76Regular Expression Matching
String, Dynamic Programming, Recursion
Hard
53
0.3%
77Power of Two
Math, Bit Manipulation, Recursion
Easy
53
0.5%
78Number of Visible People in a Queue
Array, Stack, Monotonic Stack
Hard
53
0.7%
79Set Matrix Zeroes
Array, Hash Table, Matrix
Medium
52
0.6%
80Find Median from Data Stream
Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream
Hard
52
0.5%
81Find First and Last Position of Element in Sorted Array
Array, Binary Search
Medium
52
0.5%
82Maximal Square
Array, Dynamic Programming, Matrix
Medium
52
0.5%
83Subsets
Array, Backtracking, Bit Manipulation
Medium
52
0.8%
84Course Schedule
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
52
0.5%
85Binary Search
Array, Binary Search
Easy
51
0.6%
86Valid Palindrome
Two Pointers, String
Easy
51
0.5%
87Basic Calculator
Math, String, Stack, Recursion
Hard
51
0.5%
88Maximal Rectangle
Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
Hard
51
0.6%
89Rotting Oranges
Array, Breadth-First Search, Matrix
Medium
51
0.6%
90Remove Nth Node From End of List
Linked List, Two Pointers
Medium
51
0.5%
91Contains Duplicate
Array, Hash Table, Sorting
Easy
51
0.6%
92Min Stack
Stack, Design
Medium
51
0.6%
93Intersection of Two Arrays
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
51
0.8%
94Permutations
Array, Backtracking
Medium
51
0.8%
95Unique Paths
Math, Dynamic Programming, Combinatorics
Medium
50
0.7%
96Sqrt(x)
Math, Binary Search
Easy
50
0.4%
97Merge k Sorted Lists
Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort
Hard
50
0.6%
98Maximum Product Subarray
Array, Dynamic Programming
Medium
50
0.4%
99Coin Change
Array, Dynamic Programming, Breadth-First Search
Medium
49
0.5%
100Count Number of Trapezoids II
Array, Hash Table, Math, Geometry
Hard
49
0.4%
1013Sum Closest
Array, Two Pointers, Sorting
Medium
49
0.5%
102Palindrome Linked List
Linked List, Two Pointers, Stack, Recursion
Easy
49
0.6%
103Binary Tree Maximum Path Sum
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
49
0.4%
104First Missing Positive
Array, Hash Table
Hard
49
0.4%
105Max Consecutive Ones III
Array, Binary Search, Sliding Window, Prefix Sum
Medium
48
0.7%
106Two Sum II - Input Array Is Sorted
Array, Two Pointers, Binary Search
Medium
48
0.7%
107Fruit Into Baskets
Array, Hash Table, Sliding Window
Medium
48
0.5%
108Reverse Words in a String
Two Pointers, String
Medium
48
0.6%
109Insert Delete GetRandom O(1)
Array, Hash Table, Math, Design, Randomized
Medium
48
0.6%
110Sudoku Solver
Array, Hash Table, Backtracking, Matrix
Hard
48
0.7%
111Middle of the Linked List
Linked List, Two Pointers
Easy
48
0.8%
112Best Time to Buy and Sell Stock II
Array, Dynamic Programming, Greedy
Medium
47
0.7%
113Jump Game II
Array, Dynamic Programming, Greedy
Medium
47
0.4%
114Find All Numbers Disappeared in an Array
Array, Hash Table
Easy
47
0.6%
115The Earliest Moment When Everyone Become Friends
Array, Union-Find, Sorting
Medium
47
0.7%
116Valid Sudoku
Array, Hash Table, Matrix
Medium
47
0.6%
117Candy
Array, Greedy
Hard
47
0.5%
118Linked List Cycle
Hash Table, Linked List, Two Pointers
Easy
47
0.5%
119Contains Duplicate II
Array, Hash Table, Sliding Window
Easy
47
0.5%
120Reverse Nodes in k-Group
Linked List, Recursion
Hard
47
0.7%
121Zero Array Transformation I
Array, Prefix Sum
Medium
47
0.5%
122Partition Equal Subset Sum
Array, Dynamic Programming
Medium
47
0.5%
123Combination Sum
Array, Backtracking
Medium
47
0.8%
124Daily Temperatures
Array, Stack, Monotonic Stack
Medium
47
0.7%
125Running Sum of 1d Array
Array, Prefix Sum
Easy
47
0.9%
126Same Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
46
0.7%
127Guess the Word
Array, Math, String, Interactive, Game Theory
Hard
46
0.4%
128Remove K Digits
String, Stack, Greedy, Monotonic Stack
Medium
46
0.4%
129Edit Distance
String, Dynamic Programming
Medium
46
0.6%
130Count Primes
Array, Math, Enumeration, Number Theory
Medium
46
0.4%
131Peak Index in a Mountain Array
Array, Binary Search
Medium
46
0.7%
132Fibonacci Number
Math, Dynamic Programming, Recursion, Memoization
Easy
46
0.7%
133Separate Squares I
Array, Binary Search
Medium
46
0.6%
134Insert Interval
Array
Medium
46
0.5%
135Length of Last Word
String
Easy
46
0.6%
136Rotate List
Linked List, Two Pointers
Medium
46
0.4%
137Text Justification
Array, String, Simulation
Hard
46
0.5%
138Isomorphic Strings
Hash Table, String
Easy
46
0.5%
139Reverse Vowels of a String
Two Pointers, String
Easy
46
0.6%
140Sum of Subarray Minimums
Array, Dynamic Programming, Stack, Monotonic Stack
Medium
46
0.4%
141Word Break
Array, Hash Table, String, Dynamic Programming, Trie, Memoization
Medium
45
0.5%
142Sort an Array
Array, Divide and Conquer, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort
Medium
45
0.6%
143Missing Number
Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting
Easy
45
0.7%
144Palindrome Partitioning
String, Dynamic Programming, Backtracking
Medium
45
0.7%
145Minimum Area Rectangle
Array, Hash Table, Math, Geometry, Sorting
Medium
45
0.6%
146Count Number of Trapezoids I
Array, Hash Table, Math, Geometry
Medium
45
0.5%
147Second Highest Salary
Database
Medium
45
0.5%
148Find the Duplicate Number
Array, Two Pointers, Binary Search, Bit Manipulation
Medium
45
0.6%
149Next Greater Element II
Array, Stack, Monotonic Stack
Medium
45
0.7%
150Diameter of Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
45
0.7%
151Create a DataFrame from ListEasy
45
0.8%
152Wildcard Matching
String, Dynamic Programming, Greedy, Recursion
Hard
44
0.3%
153Subsets II
Array, Backtracking, Bit Manipulation
Medium
44
0.6%
154Reverse Pairs
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
44
0.3%
155Random Pick with Weight
Array, Math, Binary Search, Prefix Sum, Randomized
Medium
44
0.5%
156Capacity To Ship Packages Within D Days
Array, Binary Search
Medium
44
0.7%
157Unique Number of Occurrences
Array, Hash Table
Easy
44
0.8%
158Maximum Average Subarray I
Array, Sliding Window
Easy
44
0.5%
159Article Views I
Database
Easy
44
0.8%
160Check if Array Is Sorted and Rotated
Array
Easy
44
0.6%
161Reverse String
Two Pointers, String
Easy
43
0.8%
162Divide Two Integers
Math, Bit Manipulation
Medium
43
0.2%
163Surrounded Regions
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
43
0.5%
164Largest Number
Array, String, Greedy, Sorting
Medium
43
0.4%
165Big Countries
Database
Easy
43
0.7%
166Range Module
Design, Segment Tree, Ordered Set
Hard
43
0.5%
167String to Integer (atoi)
String
Medium
43
0.2%
168Power of Three
Math, Recursion
Easy
43
0.5%
169Target Sum
Array, Dynamic Programming, Backtracking
Medium
43
0.5%
170Word Search
Array, String, Backtracking, Depth-First Search, Matrix
Medium
43
0.5%
171String Compression
Two Pointers, String
Medium
43
0.6%
172Find Customer Referee
Database
Easy
43
0.7%
173Integer to Roman
Hash Table, Math, String
Medium
43
0.7%
174Move Pieces to Obtain a String
Two Pointers, String
Medium
43
0.6%
175Minimum Window Substring
Hash Table, String, Sliding Window
Hard
43
0.5%
176Search a 2D Matrix II
Array, Binary Search, Divide and Conquer, Matrix
Medium
43
0.6%
177Pacific Atlantic Water Flow
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
43
0.6%
178Permutation in String
Hash Table, Two Pointers, String, Sliding Window
Medium
43
0.5%
179Squares of a Sorted Array
Array, Two Pointers, Sorting
Easy
43
0.7%
180Finding MK Average
Design, Queue, Heap (Priority Queue), Data Stream, Ordered Set
Hard
43
0.4%
181Apply Substitutions
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
43
0.8%
182Search a 2D Matrix
Array, Binary Search, Matrix
Medium
42
0.5%
183First Unique Character in a String
Hash Table, String, Queue, Counting
Easy
42
0.7%
184Binary Tree Level Order Traversal
Tree, Breadth-First Search, Binary Tree
Medium
42
0.7%
185Invert Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
42
0.8%
186Meeting Rooms III
Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
Hard
42
0.5%
187Find the Difference
Hash Table, String, Bit Manipulation, Sorting
Easy
42
0.6%
188Greatest Common Divisor of Strings
Math, String
Easy
42
0.5%
189Word Ladder
Hash Table, String, Breadth-First Search
Hard
42
0.5%
190Rising Temperature
Database
Easy
42
0.5%
191Lowest Common Ancestor of a Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
42
0.7%
192Number of Provinces
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
42
0.7%
193Frequency of the Most Frequent Element
Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
Medium
42
0.4%
194Next Greater Element I
Array, Hash Table, Stack, Monotonic Stack
Easy
41
0.8%
195Remove Duplicates from Sorted List
Linked List
Easy
41
0.6%
196Employees Earning More Than Their Managers
Database
Easy
41
0.7%
197Majority Element II
Array, Hash Table, Sorting, Counting
Medium
41
0.6%
198Burst Balloons
Array, Dynamic Programming
Hard
41
0.6%
199Delete Nodes And Return Forest
Array, Hash Table, Tree, Depth-First Search, Binary Tree
Medium
41
0.7%
200Kth Smallest Element in a BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
41
0.8%
201Swap Adjacent in LR String
Two Pointers, String
Medium
41
0.4%
202Symmetric Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
41
0.6%
203Minimum Size Subarray Sum
Array, Binary Search, Sliding Window, Prefix Sum
Medium
41
0.5%
204Is Subsequence
Two Pointers, String, Dynamic Programming
Easy
41
0.5%
205Maximum Width Ramp
Array, Two Pointers, Stack, Monotonic Stack
Medium
41
0.6%
206Largest Divisible Subset
Array, Math, Dynamic Programming, Sorting
Medium
40
0.5%
207Add Strings
Math, String, Simulation
Easy
40
0.5%
208Sort List
Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort
Medium
40
0.6%
209Intersection of Two Linked Lists
Hash Table, Linked List, Two Pointers
Easy
40
0.6%
210Swim in Rising Water
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Hard
40
0.7%
211Minimum Number of Days to Make m Bouquets
Array, Binary Search
Medium
40
0.6%
212Clone Graph
Hash Table, Depth-First Search, Breadth-First Search, Graph Theory
Medium
40
0.7%
21324 Game
Array, Math, Backtracking
Hard
40
0.6%
214Count Good Numbers
Math, Recursion
Medium
40
0.6%
215Longest Valid Parentheses
String, Dynamic Programming, Stack
Hard
40
0.4%
216Remove Duplicates from Sorted Array II
Array, Two Pointers
Medium
40
0.6%
217Gas Station
Array, Greedy
Medium
40
0.5%
218First Bad Version
Binary Search, Interactive
Easy
40
0.5%
219Perfect Squares
Math, Dynamic Programming, Breadth-First Search
Medium
40
0.6%
220Odd Even Linked List
Linked List
Medium
40
0.6%
221Task Scheduler
Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
40
0.6%
222Find K Closest Elements
Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue)
Medium
40
0.5%
223Copy List with Random Pointer
Hash Table, Linked List
Medium
39
0.6%
224Trapping Rain Water II
Array, Breadth-First Search, Heap (Priority Queue), Matrix
Hard
39
0.6%
225Rotate String
String, String Matching
Easy
39
0.7%
226Longest Common Subsequence
String, Dynamic Programming
Medium
39
0.6%
227Reverse Linked List II
Linked List
Medium
39
0.5%
228Binary Tree Inorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
39
0.8%
229Binary Tree Zigzag Level Order Traversal
Tree, Breadth-First Search, Binary Tree
Medium
39
0.6%
230Summary Ranges
Array
Easy
39
0.5%
231Ransom Note
Hash Table, String, Counting
Easy
39
0.7%
232Fizz Buzz
Math, String, Simulation
Easy
39
0.8%
233Zero Array Transformation II
Array, Two Pointers, Binary Search, Prefix Sum
Medium
39
0.4%
234Single Number II
Array, Bit Manipulation
Medium
39
0.7%
235Reorder List
Linked List, Two Pointers, Stack, Recursion
Medium
39
0.7%
236Shortest Palindrome
String, Rolling Hash, String Matching, Hash Function
Hard
39
0.4%
237Implement Stack using Queues
Stack, Design, Queue
Easy
39
0.7%
238Find Minimum in Rotated Sorted Array
Array, Binary Search
Medium
39
0.5%
239Serialize and Deserialize Binary Tree
String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree
Hard
39
0.6%
240Longest Increasing Path in a Matrix
Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Memoization, Matrix
Hard
39
0.6%
24101 Matrix
Array, Dynamic Programming, Breadth-First Search, Matrix
Medium
39
0.5%
242Asteroid Collision
Array, Stack, Simulation
Medium
39
0.5%
243Average Time of Process per Machine
Database
Easy
39
0.7%
244Group Shifted Strings
Array, Hash Table, String
Medium
38
0.7%
245CounterEasy
38
0.8%
246Swap Nodes in Pairs
Linked List, Recursion
Medium
38
0.7%
247Search in Rotated Sorted Array II
Array, Binary Search
Medium
38
0.4%
248Coin Change II
Array, Dynamic Programming
Medium
38
0.6%
249Can Place Flowers
Array, Greedy
Easy
38
0.3%
250Reorganize String
Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
38
0.6%
251Shortest Path in a Grid with Obstacles Elimination
Array, Breadth-First Search, Matrix
Hard
38
0.5%
252Evaluate Division
Array, String, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Shortest Path
Medium
38
0.6%
253Evaluate Reverse Polish Notation
Array, Math, Stack
Medium
38
0.6%
254Expression Add Operators
Math, String, Backtracking
Hard
38
0.4%
255Sum of Two Integers
Math, Bit Manipulation
Medium
38
0.6%
256LFU Cache
Hash Table, Linked List, Design, Doubly-Linked List
Hard
38
0.5%
257Minimum Area Rectangle II
Array, Hash Table, Math, Geometry
Medium
38
0.6%
258Count Square Submatrices with All Ones
Array, Dynamic Programming, Matrix
Medium
38
0.8%
259Find Missing and Repeated Values
Array, Hash Table, Math, Matrix
Easy
38
0.8%
260Number of Islands II
Array, Hash Table, Union-Find
Hard
37
0.4%
261Valid Palindrome II
Two Pointers, String, Greedy
Easy
37
0.4%
262Odd Even Jump
Array, Dynamic Programming, Stack, Sorting, Monotonic Stack, Ordered Set
Hard
37
0.4%
263Find All Possible Recipes from Given Supplies
Array, Hash Table, String, Graph Theory, Topological Sort
Medium
37
0.6%
264Lexicographically Smallest Beautiful String
String, Greedy
Hard
37
0.4%
265Permutation Sequence
Math, Recursion
Hard
37
0.5%
266Maximum Depth of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
37
0.8%
267Implement Trie (Prefix Tree)
Hash Table, String, Design, Trie
Medium
37
0.7%
268House Robber II
Array, Dynamic Programming
Medium
37
0.5%
269Find All Duplicates in an Array
Array, Hash Table, Sorting
Medium
37
0.8%
270Race Car
Dynamic Programming
Hard
37
0.4%
271Online Stock Span
Stack, Design, Monotonic Stack, Data Stream
Medium
37
0.7%
272Path With Minimum Effort
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Medium
37
0.6%
273Can Make Arithmetic Progression From Sequence
Array, Sorting
Easy
37
0.7%
274Word Search II
Array, String, Backtracking, Trie, Matrix
Hard
37
0.4%
275Moving Average from Data Stream
Array, Design, Queue, Data Stream
Easy
37
0.8%
276Cheapest Flights Within K Stops
Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
37
0.4%
277Binary Subarrays With Sum
Array, Hash Table, Sliding Window, Prefix Sum
Medium
37
0.7%
278Simplify Path
String, Stack
Medium
37
0.5%
279Course Schedule II
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
37
0.6%
280Alien Dictionary
Array, String, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
37
0.4%
281Contiguous Array
Array, Hash Table, Prefix Sum
Medium
37
0.5%
282Number of Matching Subsequences
Array, Hash Table, String, Binary Search, Dynamic Programming, Trie, Sorting
Medium
37
0.5%
283Minimum Path Sum
Array, Dynamic Programming, Matrix
Medium
36
0.7%
284Network Delay Time
Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
36
0.6%
285Multiply Strings
Math, String, Simulation
Medium
36
0.4%
286Linked List Cycle II
Hash Table, Linked List, Two Pointers
Medium
36
0.6%
287Implement Queue using Stacks
Stack, Design, Queue
Easy
36
0.7%
288Add Digits
Math, Simulation, Number Theory
Easy
36
0.7%
289Assign Cookies
Array, Two Pointers, Greedy, Sorting
Easy
36
0.6%
290Employee Bonus
Database
Easy
36
0.8%
291Redundant Connection
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
36
0.7%
292Maximum Swap
Math, Greedy
Medium
36
0.5%
293Minimum Number of Operations to Move All Balls to Each Box
Array, String, Prefix Sum
Medium
36
0.9%
294Minimum Time to Finish the Race
Array, Dynamic Programming
Hard
36
0.4%
295Validate Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
36
0.4%
296Construct Binary Tree from Preorder and Inorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
36
0.7%
297Delete Node in a Linked List
Linked List
Medium
36
0.8%
298H-Index
Array, Sorting, Counting Sort
Medium
36
0.4%
299Design Hit Counter
Array, Binary Search, Design, Queue, Data Stream
Medium
36
0.7%
300Find K Pairs with Smallest Sums
Array, Heap (Priority Queue)
Medium
36
0.4%
301Repeated Substring Pattern
String, String Matching
Easy
36
0.5%
302Diagonal Traverse
Array, Matrix, Simulation
Medium
36
0.7%
303Accounts Merge
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting
Medium
36
0.6%
304Find And Replace in String
Array, Hash Table, String, Sorting
Medium
36
0.5%
305Min Cost Climbing Stairs
Array, Dynamic Programming
Easy
35
0.7%
306Substring with Concatenation of All Words
Hash Table, String, Sliding Window
Hard
35
0.3%
307Triangle
Array, Dynamic Programming
Medium
35
0.6%
308Managers with at Least 5 Direct Reports
Database
Medium
35
0.5%
309Domino and Tromino Tiling
Dynamic Programming
Medium
35
0.5%
310Vertical Order Traversal of a Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
Hard
35
0.5%
311Snapshot Array
Array, Hash Table, Binary Search, Design
Medium
35
0.4%
312Kth Missing Positive Number
Array, Binary Search
Easy
35
0.6%
313Best Time to Buy and Sell Stock with Cooldown
Array, Dynamic Programming
Medium
35
0.6%
314Combination Sum IV
Array, Dynamic Programming
Medium
35
0.6%
315Reverse String II
Two Pointers, String
Easy
35
0.5%
316Set Mismatch
Array, Hash Table, Bit Manipulation, Sorting
Easy
35
0.4%
317Richest Customer Wealth
Array, Matrix
Easy
35
0.9%
318Detect Squares
Array, Hash Table, Design, Counting, Data Stream
Medium
35
0.5%
319Find Longest Special Substring That Occurs Thrice I
Hash Table, String, Binary Search, Sliding Window, Counting
Medium
35
0.6%
320Rearrange Array Elements by Sign
Array, Two Pointers, Simulation
Medium
35
0.8%
321Integer to English Words
Math, String, Recursion
Hard
35
0.4%
322Remove Duplicate Letters
String, Stack, Greedy, Monotonic Stack
Medium
35
0.5%
323Find Eventual Safe States
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
35
0.7%
324Backspace String Compare
Two Pointers, String, Stack, Simulation
Easy
35
0.5%
325Shuffle the Array
Array
Easy
35
0.9%
326Single-Threaded CPU
Array, Sorting, Heap (Priority Queue)
Medium
35
0.5%
327The Skyline Problem
Array, Divide and Conquer, Binary Indexed Tree, Segment Tree, Sweep Line, Sorting, Heap (Priority Queue), Ordered Set
Hard
34
0.5%
328Count of Smaller Numbers After Self
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
34
0.4%
329Exclusive Time of Functions
Array, Stack
Medium
34
0.7%
330Bus Routes
Array, Hash Table, Breadth-First Search
Hard
34
0.5%
331Rank Transform of an Array
Array, Hash Table, Sorting
Easy
34
0.7%
332Number of Closed Islands
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
34
0.7%
333The Latest Time to Catch a Bus
Array, Two Pointers, Binary Search, Sorting
Medium
34
0.3%
334Find the Safest Path in a Grid
Array, Binary Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Medium
34
0.5%
335Count Days Without Meetings
Array, Sorting
Medium
34
0.5%
336Combination Sum II
Array, Backtracking
Medium
34
0.6%
337Balanced Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
34
0.6%
338Nth Digit
Math, Binary Search
Medium
34
0.4%
339Sort Characters By Frequency
Hash Table, String, Sorting, Heap (Priority Queue), Bucket Sort, Counting
Medium
34
0.8%
340Kth Largest Element in a Stream
Tree, Design, Binary Search Tree, Heap (Priority Queue), Binary Tree, Data Stream
Easy
34
0.6%
341Soup Servings
Math, Dynamic Programming, Probability and Statistics
Medium
34
0.6%
342Car Fleet
Array, Stack, Sorting, Monotonic Stack
Medium
34
0.6%
343Transpose Matrix
Array, Matrix, Simulation
Easy
34
0.8%
344Subarrays with K Different Integers
Array, Hash Table, Sliding Window, Counting
Hard
34
0.7%
345Remove Outermost Parentheses
String, Stack
Easy
34
0.9%
346Shortest Path in Binary Matrix
Array, Breadth-First Search, Matrix
Medium
34
0.5%
347Score of a String
String
Easy
34
0.9%
348Average Selling Price
Database
Easy
34
0.4%
349Next Special Palindrome Number
Backtracking, Bit Manipulation
Hard
34
0.3%
350Fraction to Recurring Decimal
Hash Table, Math, String
Medium
33
0.3%
351Binary Tree Right Side View
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
33
0.7%
352Binary Tree Paths
String, Backtracking, Tree, Depth-First Search, Binary Tree
Easy
33
0.7%
353Linked List Random Node
Linked List, Math, Reservoir Sampling, Randomized
Medium
33
0.6%
354Sequence Reconstruction
Array, Graph Theory, Topological Sort
Medium
33
0.3%
355Shortest Unsorted Continuous Subarray
Array, Two Pointers, Stack, Greedy, Sorting, Monotonic Stack
Medium
33
0.4%
356Minimum Weighted Subgraph With the Required Paths
Graph Theory, Heap (Priority Queue), Shortest Path
Hard
33
0.4%
357Height of Binary Tree After Subtree Removal Queries
Array, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Hard
33
0.5%
358Maximum XOR of Two Numbers in an Array
Array, Hash Table, Bit Manipulation, Trie
Medium
33
0.5%
359Max Area of Island
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
33
0.7%
360Continuous Subarrays
Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Medium
33
0.6%
361Maximum Points You Can Obtain from Cards
Array, Sliding Window, Prefix Sum
Medium
33
0.6%
362Find Pivot Index
Array, Prefix Sum
Easy
33
0.6%
363Find X-Sum of All K-Long Subarrays I
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Easy
33
0.8%
364Flatten Binary Tree to Linked List
Linked List, Stack, Tree, Depth-First Search, Binary Tree
Medium
33
0.7%
365Reconstruct Itinerary
Array, String, Depth-First Search, Graph Theory, Sorting, Heap (Priority Queue), Eulerian Circuit
Hard
33
0.4%
366Android Unlock Patterns
Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
33
0.5%
367Champagne Tower
Dynamic Programming
Medium
33
0.6%
368Sum of Distances in Tree
Dynamic Programming, Tree, Depth-First Search, Graph Theory
Hard
33
0.7%
369Minimum Cost to Make at Least One Valid Path in a Grid
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
33
0.7%
370Unique Length-3 Palindromic Subsequences
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
33
0.7%
371Detonate the Maximum Bombs
Array, Math, Depth-First Search, Breadth-First Search, Graph Theory, Geometry
Medium
33
0.5%
372Design a Number Container System
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
33
0.6%
373Count and Say
String
Medium
33
0.6%
374Partition List
Linked List, Two Pointers
Medium
33
0.6%
375Convert Sorted Array to Binary Search Tree
Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
Easy
33
0.8%
376Remove Linked List Elements
Linked List, Recursion
Easy
33
0.5%
377Encode and Decode Strings
Array, String, Design
Medium
33
0.5%
378Find All Anagrams in a String
Hash Table, String, Sliding Window
Medium
33
0.5%
379Design a Stack With Increment Operation
Array, Stack, Design
Medium
33
0.8%
380Replace Employee ID With The Unique Identifier
Database
Easy
33
0.8%
381Customer Who Visited but Did Not Make Any Transactions
Database
Easy
33
0.7%
382Type of Triangle
Array, Math, Sorting
Easy
33
0.4%
383Combinations
Backtracking
Medium
32
0.7%
384Top K Frequent Words
Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting
Medium
32
0.6%
385Shortest Path Visiting All Nodes
Dynamic Programming, Bit Manipulation, Breadth-First Search, Graph Theory, Bitmask
Hard
32
0.7%
386Maximum Candies Allocated to K Children
Array, Binary Search
Medium
32
0.5%
387Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Medium
32
0.6%
388Partition Array Into Two Arrays to Minimize Sum Difference
Array, Two Pointers, Binary Search, Dynamic Programming, Bit Manipulation, Sorting, Ordered Set, Bitmask
Hard
32
0.2%
389Time Taken to Cross the Door
Array, Queue, Simulation
Hard
32
0.5%
390Excel Sheet Column Title
Math, String
Easy
32
0.5%
391Consecutive Numbers
Database
Medium
32
0.5%
392Range Sum Query - Immutable
Array, Design, Prefix Sum
Easy
32
0.7%
393Longest Palindrome
Hash Table, String, Greedy
Easy
32
0.6%
394Palindromic Substrings
Two Pointers, String, Dynamic Programming
Medium
32
0.7%
395Find Duplicate Subtrees
Hash Table, Tree, Depth-First Search, Binary Tree
Medium
32
0.6%
396Ugly Number
Math
Easy
32
0.4%
397Graph Valid Tree
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
31
0.5%
398Count Numbers with Unique Digits
Math, Dynamic Programming, Backtracking
Medium
31
0.6%
399Repeated String Match
String, String Matching
Medium
31
0.4%
400Largest Triangle Area
Array, Math, Geometry
Easy
31
0.7%
401Keys and Rooms
Depth-First Search, Breadth-First Search, Graph Theory
Medium
31
0.8%
402Remove Sub-Folders from the Filesystem
Array, String, Depth-First Search, Trie
Medium
31
0.8%
403Maximum Score After Splitting a String
String, Prefix Sum
Easy
31
0.7%
404Delete Nodes From Linked List Present in Array
Array, Hash Table, Linked List
Medium
31
0.7%
405Unique Paths II
Array, Dynamic Programming, Matrix
Medium
31
0.4%
406Recover Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
31
0.6%
407Word Break II
Array, Hash Table, String, Dynamic Programming, Backtracking, Trie, Memoization
Hard
31
0.6%
408Queue Reconstruction by Height
Array, Binary Indexed Tree, Segment Tree, Sorting
Medium
31
0.7%
409Predict the Winner
Array, Math, Dynamic Programming, Recursion, Game Theory
Medium
31
0.6%
410Flood Fill
Array, Depth-First Search, Breadth-First Search, Matrix
Easy
31
0.7%
411Making A Large Island
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Hard
31
0.6%
412Monthly Transactions I
Database
Medium
31
0.6%
413Students and Examinations
Database
Easy
31
0.6%
414Minimum Difference Between Largest and Smallest Value in Three Moves
Array, Greedy, Sorting
Medium
31
0.6%
415Binary Tree Vertical Order Traversal
Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
Medium
31
0.6%
416House Robber III
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Medium
31
0.6%
417Sliding Window Median
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
31
0.4%
418Maximum Sum of 3 Non-Overlapping Subarrays
Array, Dynamic Programming, Sliding Window, Prefix Sum
Hard
31
0.6%
419Minimum Falling Path Sum
Array, Dynamic Programming, Matrix
Medium
31
0.6%
420Find in Mountain Array
Array, Binary Search, Interactive
Hard
31
0.4%
421Tuple with Same Product
Array, Hash Table, Counting
Medium
31
0.7%
422Sender With Largest Word Count
Array, Hash Table, String, Counting
Medium
31
0.6%
423Decode Ways
String, Dynamic Programming
Medium
31
0.4%
424Number of 1 Bits
Divide and Conquer, Bit Manipulation
Easy
31
0.8%
425Increasing Triplet Subsequence
Array, Greedy
Medium
31
0.4%
426Flatten Nested List Iterator
Stack, Tree, Depth-First Search, Design, Queue, Iterator
Medium
31
0.7%
427Longest Absolute File Path
String, Stack, Depth-First Search
Medium
31
0.5%
428Delete Node in a BST
Tree, Binary Search Tree, Binary Tree
Medium
31
0.5%
429Jewels and Stones
Hash Table, String
Easy
31
0.9%
430Flipping an Image
Array, Two Pointers, Bit Manipulation, Matrix, Simulation
Easy
31
0.8%
431New 21 Game
Math, Dynamic Programming, Sliding Window, Probability and Statistics
Medium
31
0.5%
432Regions Cut By Slashes
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
31
0.8%
433Longest Arithmetic Subsequence of Given Difference
Array, Hash Table, Dynamic Programming
Medium
31
0.5%
434Divide Array in Sets of K Consecutive Numbers
Array, Hash Table, Greedy, Sorting
Medium
31
0.6%
435Kids With the Greatest Number of Candies
Array
Easy
31
0.9%
436Minimum Interval to Include Each Query
Array, Binary Search, Sweep Line, Sorting, Heap (Priority Queue)
Hard
31
0.5%
437Maximum Good Subarray Sum
Array, Hash Table, Prefix Sum
Medium
31
0.2%
438Maximum Number of Events That Can Be Attended
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
31
0.4%
439Inverse Coin Change
Array, Dynamic Programming
Medium
31
0.5%
440Number of Digit One
Math, Dynamic Programming, Recursion
Hard
30
0.4%
441Path Sum III
Tree, Depth-First Search, Binary Tree
Medium
30
0.5%
442Detect Capital
String
Easy
30
0.6%
443Minimum Absolute Difference in BST
Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
30
0.6%
444Valid Parenthesis String
String, Dynamic Programming, Stack, Greedy
Medium
30
0.4%
445Max Chunks To Make Sorted
Array, Stack, Greedy, Sorting, Monotonic Stack
Medium
30
0.6%
446K-th Symbol in Grammar
Math, Bit Manipulation, Recursion
Medium
30
0.5%
447Robot Room Cleaner
Backtracking, Interactive
Hard
30
0.8%
448Minimum Add to Make Parentheses Valid
String, Stack, Greedy
Medium
30
0.7%
449Minimum Domino Rotations For Equal Row
Array, Greedy
Medium
30
0.6%
450Smallest Integer Divisible by K
Hash Table, Math
Medium
30
0.5%
451Maximum Level Sum of a Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
30
0.7%
452Find the Difference of Two Arrays
Array, Hash Table
Easy
30
0.8%
453Check If N and Its Double Exist
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
30
0.4%
454Product of the Last K Numbers
Array, Math, Design, Data Stream, Prefix Sum
Medium
30
0.6%
455Number of Subsequences That Satisfy the Given Sum Condition
Array, Two Pointers, Binary Search, Sorting
Medium
30
0.5%
456Find Original Array From Doubled Array
Array, Hash Table, Greedy, Sorting
Medium
30
0.4%
457Design a Text Editor
Linked List, String, Stack, Design, Simulation, Doubly-Linked List
Hard
30
0.5%
458Maximum Beauty of an Array After Applying Operation
Array, Binary Search, Sliding Window, Sorting
Medium
30
0.6%
459Best Time to Buy and Sell Stock III
Array, Dynamic Programming
Hard
30
0.5%
460Binary Search Tree Iterator
Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator
Medium
30
0.8%
461Minimum Height Trees
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
30
0.4%
462Third Maximum Number
Array, Sorting
Easy
30
0.4%
463Non-overlapping Intervals
Array, Dynamic Programming, Greedy, Sorting
Medium
30
0.6%
464Minimum Time Difference
Array, Math, String, Sorting
Medium
30
0.6%
465My Calendar I
Array, Binary Search, Design, Segment Tree, Ordered Set
Medium
30
0.6%
466Snakes and Ladders
Array, Breadth-First Search, Matrix
Medium
30
0.5%
467K Closest Points to Origin
Array, Math, Divide and Conquer, Geometry, Sorting, Heap (Priority Queue), Quickselect
Medium
30
0.7%
468Subarray Sums Divisible by K
Array, Hash Table, Prefix Sum
Medium
30
0.6%
469Duplicate Zeros
Array, Two Pointers
Easy
30
0.5%
470How Many Numbers Are Smaller Than the Current Number
Array, Hash Table, Sorting, Counting Sort
Easy
30
0.9%
471Maximum Score From Removing Substrings
String, Stack, Greedy
Medium
30
0.7%
472Sum of Beauty of All Substrings
Hash Table, String, Counting
Medium
30
0.7%
473Range Sum Query 2D - Immutable
Array, Design, Matrix, Prefix Sum
Medium
30
0.6%
474K-th Smallest in Lexicographical Order
Trie
Hard
30
0.5%
475Remove Duplicates from Sorted List II
Linked List, Two Pointers
Medium
29
0.5%
476Missing Ranges
Array
Easy
29
0.4%
477Basic Calculator II
Math, String, Stack
Medium
29
0.5%
478Create Maximum Number
Array, Two Pointers, Stack, Greedy, Monotonic Stack
Hard
29
0.4%
479Student Attendance Record II
Dynamic Programming
Hard
29
0.6%
480Robot Return to Origin
String, Simulation
Easy
29
0.8%
481Rotated Digits
Math, Dynamic Programming
Medium
29
0.6%
482All Nodes Distance K in Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
29
0.7%
483Longest Duplicate Substring
String, Binary Search, Sliding Window, Rolling Hash, Suffix Array, Hash Function
Hard
29
0.3%
484Make The String Great
String, Stack
Easy
29
0.7%
485Minimum Operations to Reduce X to Zero
Array, Hash Table, Binary Search, Sliding Window, Prefix Sum
Medium
29
0.4%
486Build Array from Permutation
Array, Simulation
Easy
29
0.9%
487Painting a Grid With Three Different Colors
Dynamic Programming
Hard
29
0.8%
488Check if Word Can Be Placed In Crossword
Array, Matrix, Enumeration
Medium
29
0.5%
489Array Prototype LastEasy
29
0.7%
490Divide Array Into Arrays With Max Difference
Array, Greedy, Sorting
Medium
29
0.8%
491Maximum Number of Ways to Partition an Array
Array, Hash Table, Counting, Enumeration, Prefix Sum
Hard
29
0.4%
492Word Ladder II
Hash Table, String, Backtracking, Breadth-First Search
Hard
29
0.3%
493Delete the Middle Node of a Linked List
Linked List, Two Pointers
Medium
29
0.6%
494Intersection of Two Arrays II
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
29
0.6%
495Number of Enclaves
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
29
0.7%
496Number of Good Pairs
Array, Hash Table, Math, Counting
Easy
29
0.9%
497Maximum Frequency of an Element After Performing Operations I
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Medium
29
0.4%
498Walls and Gates
Array, Breadth-First Search, Matrix
Medium
28
0.6%
499Wiggle Sort II
Array, Divide and Conquer, Greedy, Sorting, Quickselect
Medium
28
0.4%
500Valid Word Abbreviation
Two Pointers, String
Easy
28
0.4%
501Optimal Account Balancing
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Hard
28
0.5%
502My Calendar II
Array, Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set
Medium
28
0.6%
503Expressive Words
Array, Two Pointers, String
Medium
28
0.5%
504Word Subsets
Array, Hash Table, String
Medium
28
0.6%
505Bag of Tokens
Array, Two Pointers, Greedy, Sorting
Medium
28
0.6%
506Longest Arithmetic Subsequence
Array, Hash Table, Binary Search, Dynamic Programming
Medium
28
0.5%
507Rank Teams by Votes
Array, Hash Table, String, Sorting, Counting
Medium
28
0.6%
508Count Submatrices With All Ones
Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
Medium
28
0.7%
509Find the Highest Altitude
Array, Prefix Sum
Easy
28
0.8%
510Maximum Score of a Node Sequence
Array, Graph Theory, Sorting, Enumeration
Hard
28
0.4%
511First Letter to Appear Twice
Hash Table, String, Bit Manipulation, Counting
Easy
28
0.8%
512Maximum Number of Points with Cost
Array, Dynamic Programming, Matrix
Medium
28
0.4%
513Permutations II
Array, Backtracking, Sorting
Medium
28
0.6%
514Binary Tree Preorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
28
0.8%
515Max Points on a Line
Array, Hash Table, Math, Geometry
Hard
28
0.3%
516Palindrome Pairs
Array, Hash Table, String, Trie, Hash Function
Hard
28
0.4%
517Island Perimeter
Array, Depth-First Search, Breadth-First Search, Matrix
Easy
28
0.7%
518Heaters
Array, Two Pointers, Binary Search, Sorting
Medium
28
0.4%
519Longest Palindromic Subsequence
String, Dynamic Programming
Medium
28
0.7%
520Triangle Judgement
Database
Easy
28
0.7%
521Two Sum IV - Input is a BST
Hash Table, Two Pointers, Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
28
0.6%
522Maximum Width of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
28
0.5%
523Is Graph Bipartite?
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
28
0.6%
524Design Linked List
Linked List, Design
Medium
28
0.3%
525Time Based Key-Value Store
Hash Table, String, Binary Search, Design
Medium
28
0.5%
526Path with Maximum Probability
Array, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
28
0.7%
527Nth Highest Salary
Database
Medium
28
0.4%
528Sum of Good Subsequences
Array, Hash Table, Dynamic Programming
Hard
28
0.3%
529Zero Array Transformation III
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
28
0.5%
530Count Special Subsequences
Array, Hash Table, Math, Enumeration
Medium
28
0.3%
531Count Number of Bad Pairs
Array, Hash Table, Math, Counting
Medium
28
0.5%
532Path Existence Queries in a Graph I
Array, Hash Table, Binary Search, Union-Find, Graph Theory
Medium
28
0.6%
533Spiral Matrix II
Array, Matrix, Simulation
Medium
28
0.8%
534Game of Life
Array, Matrix, Simulation
Medium
28
0.7%
535Shortest Distance from All Buildings
Array, Breadth-First Search, Matrix
Hard
28
0.4%
536Sort Transformed Array
Array, Math, Two Pointers, Sorting
Medium
28
0.6%
537Ones and Zeroes
Array, String, Dynamic Programming
Medium
28
0.5%
538Delete Operation for Two Strings
String, Dynamic Programming
Medium
28
0.7%
539Magic Squares In Grid
Array, Hash Table, Math, Matrix
Medium
28
0.6%
540Longest Mountain in Array
Array, Two Pointers, Dynamic Programming, Enumeration
Medium
28
0.4%
541X of a Kind in a Deck of Cards
Array, Hash Table, Math, Counting, Number Theory
Easy
28
0.3%
542Filling Bookcase Shelves
Array, Dynamic Programming
Medium
28
0.7%
543Count Servers that Communicate
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix, Counting
Medium
28
0.7%
544Find the Smallest Divisor Given a Threshold
Array, Binary Search
Medium
28
0.7%
545Stone Game III
Array, Math, Dynamic Programming, Game Theory
Hard
28
0.6%
546Build an Array With Stack Operations
Array, Stack, Simulation
Medium
28
0.8%
547Longest Subarray of 1's After Deleting One Element
Array, Dynamic Programming, Sliding Window
Medium
28
0.7%
548Parallel Courses II
Dynamic Programming, Bit Manipulation, Graph Theory, Bitmask
Hard
28
0.3%
549Find the Most Competitive Subsequence
Array, Stack, Greedy, Monotonic Stack
Medium
28
0.5%
550Minimum Number of Flips to Make the Binary String Alternating
String, Dynamic Programming, Sliding Window
Medium
28
0.5%
551Convert 1D Array Into 2D Array
Array, Matrix, Simulation
Easy
28
0.7%
552Stock Price Fluctuation
Hash Table, Design, Heap (Priority Queue), Data Stream, Ordered Set
Medium
28
0.5%
553Find Target Indices After Sorting Array
Array, Binary Search, Sorting
Easy
28
0.8%
554Counting Words With a Given Prefix
Array, String, String Matching
Easy
28
0.8%
555Find All K-Distant Indices in an Array
Array, Two Pointers
Easy
28
0.8%
556To Be Or Not To BeEasy
28
0.6%
557Maximum Number of K-Divisible Components
Tree, Depth-First Search
Hard
28
0.7%
558Interleaving String
String, Dynamic Programming
Medium
28
0.4%
559Path Sum
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
28
0.6%
560Pascal's Triangle II
Array, Dynamic Programming
Easy
28
0.7%
561Duplicate Emails
Database
Easy
28
0.7%
562Number of Ways to Build Sturdy Brick Wall
Array, Dynamic Programming, Bit Manipulation, Bitmask
Medium
28
0.5%
563Maximum Product of Word Lengths
Array, String, Bit Manipulation
Medium
28
0.6%
564Relative Ranks
Array, Sorting, Heap (Priority Queue)
Easy
28
0.7%
565RLE Iterator
Array, Design, Counting, Iterator
Medium
28
0.6%
566Interval List Intersections
Array, Two Pointers, Sweep Line
Medium
28
0.7%
567Shortest Common Supersequence
String, Dynamic Programming
Hard
28
0.6%
568The kth Factor of n
Math, Number Theory
Medium
28
0.7%
569Minimum Cost to Cut a Stick
Array, Dynamic Programming, Sorting
Hard
28
0.6%
570Water Bottles
Math, Simulation
Easy
28
0.7%
571Lexicographical Numbers
Depth-First Search, Trie
Medium
28
0.8%
572Invalid Tweets
Database
Easy
28
0.9%
573Check if Grid can be Cut into Sections
Array, Sorting
Medium
28
0.7%
574Reschedule Meetings for Maximum Free Time I
Array, Greedy, Sliding Window
Medium
28
0.5%
575Customers Who Never Order
Database
Easy
28
0.7%
576Longest Non-Decreasing Subarray After Replacing at Most One Element
Array, Dynamic Programming
Medium
28
0.2%
577Rank Scores
Database
Medium
27
0.7%
578Best Time to Buy and Sell Stock IV
Array, Dynamic Programming
Hard
27
0.5%
579Lowest Common Ancestor of a Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
27
0.7%
580Find Leaves of Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
27
0.8%
581Kth Smallest Element in a Sorted Matrix
Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
Medium
27
0.6%
582Binary Watch
Backtracking, Bit Manipulation
Easy
27
0.7%
583Find Mode in Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
27
0.6%
584Subarray Product Less Than K
Array, Binary Search, Sliding Window, Prefix Sum
Medium
27
0.5%
585Largest Number At Least Twice of Others
Array, Sorting
Easy
27
0.5%
586Pyramid Transition Matrix
Hash Table, String, Backtracking, Bit Manipulation
Medium
27
0.6%
587Construct Binary Tree from Preorder and Postorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
27
0.8%
588Unique Email Addresses
Array, Hash Table, String
Easy
27
0.7%
589Matrix Block Sum
Array, Matrix, Prefix Sum
Medium
27
0.8%
590Kth Ancestor of a Tree Node
Binary Search, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search, Breadth-First Search, Design
Hard
27
0.4%
591Maximum Side Length of a Square with Sum Less than or Equal to Threshold
Array, Binary Search, Matrix, Prefix Sum
Medium
27
0.7%
592Number of Substrings Containing All Three Characters
Hash Table, String, Sliding Window
Medium
27
0.7%
593Minimize Hamming Distance After Swap Operations
Array, Depth-First Search, Union-Find
Medium
27
0.7%
594Largest Submatrix With Rearrangements
Array, Greedy, Sorting, Matrix
Medium
27
0.8%
595Evaluate the Bracket Pairs of a String
Array, Hash Table, String
Medium
27
0.7%
596Describe the Painting
Array, Hash Table, Sorting, Prefix Sum
Medium
27
0.5%
597Find All People With Secret
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Sorting
Hard
27
0.5%
598Words Within Two Edits of Dictionary
Array, String, Trie
Medium
27
0.7%
599Merge Two 2D Arrays by Summing Values
Array, Hash Table, Two Pointers
Easy
27
0.8%
600Find if Path Exists in Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Easy
27
0.6%
601Distinct Subsequences
String, Dynamic Programming
Hard
27
0.5%
602Sum Root to Leaf Numbers
Tree, Depth-First Search, Binary Tree
Medium
27
0.7%
603Longest Increasing Subsequence II
Array, Divide and Conquer, Dynamic Programming, Binary Indexed Tree, Segment Tree, Queue, Monotonic Queue
Hard
27
0.3%
604Design Search Autocomplete System
String, Depth-First Search, Design, Trie, Sorting, Heap (Priority Queue), Data Stream
Hard
27
0.5%
605Toeplitz Matrix
Array, Matrix
Easy
27
0.7%
606Design Circular Queue
Array, Linked List, Design, Queue
Medium
27
0.5%
607Buddy Strings
Hash Table, String
Easy
27
0.3%
608Shortest Subarray with Sum at Least K
Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue
Hard
27
0.3%
609Maximum Sum Circular Subarray
Array, Divide and Conquer, Dynamic Programming, Queue, Monotonic Queue
Medium
27
0.5%
610Number of Recent Calls
Design, Queue, Data Stream
Easy
27
0.8%
611Valid Mountain Array
Array
Easy
27
0.4%
612Minimum Cost to Merge Stones
Array, Dynamic Programming, Prefix Sum
Hard
27
0.5%
613Car Pooling
Array, Sorting, Heap (Priority Queue), Simulation, Prefix Sum
Medium
27
0.6%
614Find the Maximum Length of Valid Subsequence I
Array, Dynamic Programming
Medium
27
0.5%
615Time Needed to Inform All Employees
Tree, Depth-First Search, Breadth-First Search
Medium
27
0.6%
616Furthest Building You Can Reach
Array, Greedy, Heap (Priority Queue)
Medium
27
0.5%
617Minimum Deletions to Make String Balanced
String, Dynamic Programming, Stack
Medium
27
0.7%
618Find the Length of the Longest Common Prefix
Array, Hash Table, String, Trie
Medium
27
0.6%
619Project Employees I
Database
Easy
27
0.7%
620Adjacent Increasing Subarrays Detection I
Array
Easy
27
0.5%
621Maximum Number of Distinct Elements After Operations
Array, Greedy, Sorting
Medium
27
0.5%
622Find the Prefix Common Array of Two Arrays
Array, Hash Table, Bit Manipulation
Medium
27
0.9%
623Number of Connected Components in an Undirected Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
26
0.7%
624Count of Range Sum
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
26
0.4%
625Power of Four
Math, Bit Manipulation, Recursion
Easy
26
0.5%
626Guess Number Higher or Lower
Binary Search, Interactive
Easy
26
0.6%
627Push Dominoes
Two Pointers, String, Dynamic Programming
Medium
26
0.6%
628Maximize Distance to Closest Person
Array
Medium
26
0.5%
629Boats to Save People
Array, Two Pointers, Greedy, Sorting
Medium
26
0.6%
630Cat and Mouse
Math, Dynamic Programming, Graph Theory, Topological Sort, Memoization, Game Theory
Hard
26
0.4%
631Flip String to Monotone Increasing
String, Dynamic Programming
Medium
26
0.6%
632Knight Dialer
Dynamic Programming
Medium
26
0.6%
633Delete Columns to Make Sorted
Array, String
Easy
26
0.8%
634Flip Equivalent Binary Trees
Tree, Depth-First Search, Binary Tree
Medium
26
0.7%
635Delete Columns to Make Sorted II
Array, String, Greedy
Medium
26
0.5%
636Minimum Knight Moves
Breadth-First Search
Medium
26
0.4%
637Sort Integers by The Power Value
Dynamic Programming, Memoization, Sorting
Medium
26
0.7%
638Check If a String Contains All Binary Codes of Size K
Hash Table, String, Bit Manipulation, Rolling Hash, Hash Function
Medium
26
0.6%
639Arithmetic Subarrays
Array, Hash Table, Sorting
Medium
26
0.8%
640The Earliest and Latest Rounds Where Players Compete
Dynamic Programming, Memoization
Hard
26
0.7%
641Number of Unique Good Subsequences
String, Dynamic Programming
Hard
26
0.5%
642Find the Number of Ways to Place People I
Array, Math, Geometry, Sorting, Enumeration
Medium
26
0.6%
643Reverse Bits
Divide and Conquer, Bit Manipulation
Easy
26
0.7%
644Count Complete Tree Nodes
Binary Search, Bit Manipulation, Tree, Binary Tree
Easy
26
0.7%
645Number of Flowers in Full Bloom
Array, Hash Table, Binary Search, Sorting, Prefix Sum, Ordered Set
Hard
26
0.6%
646Bulls and Cows
Hash Table, String, Counting
Medium
26
0.5%
647Minimum Obstacle Removal to Reach Corner
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
26
0.7%
648Valid Perfect Square
Math, Binary Search
Easy
26
0.5%
649Sort Array By Parity
Array, Two Pointers, Sorting
Easy
26
0.8%
650Shortest Bridge
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
26
0.6%
651Smallest String Starting From Leaf
String, Backtracking, Tree, Depth-First Search, Binary Tree
Medium
26
0.6%
652Remove All Adjacent Duplicates In String
String, Stack
Easy
26
0.7%
653Defanging an IP Address
String
Easy
26
0.9%
654User Activity for the Past 30 Days I
Database
Easy
26
0.5%
655Product Price at a Given Date
Database
Medium
26
0.6%
656Queries Quality and Percentage
Database
Easy
26
0.5%
657Special Positions in a Binary Matrix
Array, Matrix
Easy
26
0.7%
658All O`one Data Structure
Hash Table, Linked List, Design, Doubly-Linked List
Hard
26
0.4%
659Special Array I
Array
Easy
26
0.8%
660Longest Harmonious Subsequence
Array, Hash Table, Sliding Window, Sorting, Counting
Easy
26
0.6%
661Path With Maximum Minimum Value
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Medium
26
0.5%
662Populating Next Right Pointers in Each Node
Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
25
0.7%
663Wiggle Sort
Array, Greedy, Sorting
Medium
25
0.7%
664Max Sum of Rectangle No Larger Than K
Array, Binary Search, Matrix, Prefix Sum, Ordered Set
Hard
25
0.5%
665UTF-8 Validation
Array, Bit Manipulation
Medium
25
0.5%
666Integer Replacement
Dynamic Programming, Greedy, Bit Manipulation, Memoization
Medium
25
0.4%
667The Maze
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
25
0.6%
668Longest Word in Dictionary through Deleting
Array, Two Pointers, String, Sorting
Medium
25
0.5%
669Student Attendance Record I
String
Easy
25
0.5%
670Sum of Square Numbers
Math, Two Pointers, Binary Search
Medium
25
0.4%
671Implement Magic Dictionary
Hash Table, String, Depth-First Search, Design, Trie
Medium
25
0.6%
672Cracking the Safe
String, Depth-First Search, Graph Theory, Eulerian Circuit
Hard
25
0.6%
673Escape The Ghosts
Array, Math
Medium
25
0.6%
674Insert into a Sorted Circular Linked List
Linked List
Medium
25
0.4%
675Similar String Groups
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find
Hard
25
0.6%
676Online Election
Array, Hash Table, Binary Search, Design
Medium
25
0.5%
677Beautiful Array
Array, Math, Divide and Conquer
Medium
25
0.7%
678Largest Component Size by Common Factor
Array, Hash Table, Math, Union-Find, Number Theory
Hard
25
0.4%
679Stream of Characters
Array, String, Design, Trie, Data Stream
Hard
25
0.5%
680Longest String Chain
Array, Hash Table, Two Pointers, String, Dynamic Programming, Sorting
Medium
25
0.6%
681Remove Interval
Array
Medium
25
0.7%
682Rank Transform of a Matrix
Array, Union-Find, Graph Theory, Topological Sort, Sorting, Matrix
Hard
25
0.4%
683Watering Plants
Array, Simulation
Medium
25
0.8%
684Tiling a Rectangle with the Fewest Squares
Backtracking
Hard
25
0.6%
685Minimum Remove to Make Valid Parentheses
String, Stack
Medium
25
0.7%
686Minimum Distance to Type a Word Using Two Fingers
String, Dynamic Programming
Hard
25
0.7%
687Jump Game IV
Array, Hash Table, Breadth-First Search
Hard
25
0.5%
688Number of Ways of Cutting a Pizza
Array, Dynamic Programming, Memoization, Matrix, Prefix Sum
Hard
25
0.6%
689Range Sum of Sorted Subarray Sums
Array, Two Pointers, Binary Search, Sorting, Prefix Sum
Medium
25
0.6%
690Number of Good Ways to Split a String
Hash Table, String, Dynamic Programming, Bit Manipulation, Prefix Sum
Medium
25
0.7%
691Split a String Into the Max Number of Unique Substrings
Hash Table, String, Backtracking
Medium
25
0.7%
692Special Array With X Elements Greater Than or Equal X
Array, Binary Search, Sorting
Easy
25
0.7%
693Maximum XOR With an Element From Array
Array, Bit Manipulation, Trie
Hard
25
0.6%
694Jump Game VII
String, Dynamic Programming, Sliding Window, Prefix Sum
Medium
25
0.4%
695Number of Zero-Filled Subarrays
Array, Math
Medium
25
0.7%
696Build a Matrix With Conditions
Array, Graph Theory, Topological Sort, Matrix
Hard
25
0.8%
697Number of Good Paths
Array, Hash Table, Tree, Union-Find, Graph Theory, Sorting
Hard
25
0.6%
698Find the Maximum Length of Valid Subsequence II
Array, Dynamic Programming
Medium
25
0.6%
699Unique Binary Search Trees II
Dynamic Programming, Backtracking, Tree, Binary Search Tree, Binary Tree
Medium
25
0.6%
700Convert Sorted List to Binary Search Tree
Linked List, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
Medium
25
0.7%
701Dungeon Game
Array, Dynamic Programming, Matrix
Hard
25
0.4%
702Design Add and Search Words Data Structure
String, Depth-First Search, Design, Trie
Medium
25
0.5%
703Range Sum Query 2D - Mutable
Array, Design, Binary Indexed Tree, Segment Tree, Matrix
Medium
25
0.5%
704Counting Bits
Dynamic Programming, Bit Manipulation
Easy
25
0.8%
705Largest Local Values in a Matrix
Array, Matrix
Easy
25
0.9%
706132 Pattern
Array, Binary Search, Stack, Monotonic Stack, Ordered Set
Medium
25
0.3%
707Continuous Subarray Sum
Array, Hash Table, Math, Prefix Sum
Medium
25
0.3%
708Next Closest Time
Hash Table, String, Backtracking, Enumeration
Medium
25
0.5%
709Number of Atoms
Hash Table, String, Stack, Sorting
Hard
25
0.7%
710Employee Free Time
Array, Sweep Line, Sorting, Heap (Priority Queue)
Hard
25
0.7%
711Random Point in Non-overlapping Rectangles
Array, Math, Binary Search, Reservoir Sampling, Prefix Sum, Ordered Set, Randomized
Medium
25
0.4%
712Game Play Analysis IV
Database
Medium
25
0.4%
713Immediate Food Delivery II
Database
Medium
25
0.6%
714Path with Maximum Gold
Array, Backtracking, Matrix
Medium
25
0.7%
715Count Number of Nice Subarrays
Array, Hash Table, Math, Sliding Window, Prefix Sum
Medium
25
0.8%
716Cherry Pickup II
Array, Dynamic Programming, Matrix
Hard
25
0.7%
717Nim Game
Math, Brainteaser, Game Theory
Easy
25
0.6%
718Exchange Seats
Database
Medium
25
0.7%
719Find the Maximum Sequence Value of Array
Array, Dynamic Programming, Bit Manipulation
Hard
25
0.2%
720Maximum Frequency of an Element After Performing Operations II
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Hard
25
0.5%
721Find Numbers with Even Number of Digits
Array, Math
Easy
25
0.8%
722Find N Unique Integers Sum up to Zero
Array, Math
Easy
25
0.8%
723Count Non-Decreasing Subarrays After K Operations
Array, Stack, Segment Tree, Queue, Sliding Window, Monotonic Stack, Monotonic Queue
Hard
25
0.2%
724Minimum Pair Removal to Sort Array I
Array, Hash Table, Linked List, Heap (Priority Queue), Simulation, Doubly-Linked List, Ordered Set
Easy
25
0.7%
725Fill a Special Grid
Array, Divide and Conquer, Matrix
Medium
25
0.7%
726Factorial Trailing Zeroes
Math
Medium
23
0.5%
7273Sum Smaller
Array, Two Pointers, Binary Search, Sorting
Medium
23
0.5%
728Paint Fence
Dynamic Programming
Medium
23
0.5%
729Word Pattern
Hash Table, String
Easy
23
0.4%
730Verify Preorder Serialization of a Binary Tree
String, Stack, Tree, Binary Tree
Medium
23
0.5%
731Rearrange String k Distance Apart
Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
Hard
23
0.4%
732Perfect Rectangle
Array, Hash Table, Math, Geometry, Sweep Line
Hard
23
0.4%
733Frog Jump
Array, Dynamic Programming
Hard
23
0.5%
734Sentence Screen Fitting
Array, String, Dynamic Programming
Medium
23
0.4%
735Magical String
Two Pointers, String
Medium
23
0.6%
736Encode and Decode TinyURL
Hash Table, String, Design, Hash Function
Medium
23
0.9%
737Non-decreasing Array
Array
Medium
23
0.3%
738Find K-th Smallest Pair Distance
Array, Two Pointers, Binary Search, Sorting
Hard
23
0.5%
739Sentence Similarity II
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find
Medium
23
0.5%
740Max Chunks To Make Sorted II
Array, Stack, Greedy, Sorting, Monotonic Stack
Hard
23
0.5%
741Minimize Max Distance to Gas Station
Array, Binary Search
Hard
23
0.5%
742Image Overlap
Array, Matrix
Medium
23
0.6%
743Exam Room
Design, Heap (Priority Queue), Ordered Set
Medium
23
0.4%
744All Possible Full Binary Trees
Dynamic Programming, Tree, Recursion, Memoization, Binary Tree
Medium
23
0.8%
745DI String Match
Array, Two Pointers, String, Greedy
Easy
23
0.8%
746Most Stones Removed with Same Row or Column
Hash Table, Depth-First Search, Union-Find, Graph Theory
Medium
23
0.6%
747Minimum Cost For Tickets
Array, Dynamic Programming
Medium
23
0.7%
748Campus Bikes
Array, Sorting, Heap (Priority Queue)
Medium
23
0.6%
749Video Stitching
Array, Dynamic Programming, Greedy
Medium
23
0.5%
750Letter Tile Possibilities
Hash Table, String, Backtracking, Counting
Medium
23
0.8%
751Print in Order
Concurrency
Easy
23
0.7%
752Decompress Run-Length Encoded List
Array
Easy
23
0.9%
753Minimum Number of Vertices to Reach All Nodes
Graph Theory
Medium
23
0.8%
754Minimum Number of Days to Eat N Oranges
Dynamic Programming, Memoization
Hard
23
0.4%
755Cat and Mouse II
Array, Math, Dynamic Programming, Graph Theory, Topological Sort, Memoization, Matrix, Game Theory
Hard
23
0.4%
756Checking Existence of Edge Length Limited Paths
Array, Two Pointers, Union-Find, Graph Theory, Sorting
Hard
23
0.6%
757Latest Time by Replacing Hidden Digits
String, Greedy
Easy
23
0.4%
758Map of Highest Peak
Array, Breadth-First Search, Matrix
Medium
23
0.8%
759Maximum Score of a Good Subarray
Array, Two Pointers, Binary Search, Stack, Monotonic Stack
Hard
23
0.6%
760Sentence Similarity III
Array, Two Pointers, String
Medium
23
0.5%
761Eliminate Maximum Number of Monsters
Array, Greedy, Sorting
Medium
23
0.5%
762The Number of Weak Characters in the Game
Array, Stack, Greedy, Sorting, Monotonic Stack
Medium
23
0.4%
763Parallel Courses III
Array, Dynamic Programming, Graph Theory, Topological Sort
Hard
23
0.7%
764Maximum Number of Words Found in Sentences
Array, String
Easy
23
0.9%
765Destroying Asteroids
Array, Greedy, Sorting
Medium
23
0.6%
766Paths in Matrix Whose Sum Is Divisible by K
Array, Dynamic Programming, Matrix
Hard
23
0.6%
767Count Number of Distinct Integers After Reverse Operations
Array, Hash Table, Math, Counting
Medium
23
0.8%
768Closest Nodes Queries in a Binary Search Tree
Array, Binary Search, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
23
0.4%
769Frog Jump II
Array, Binary Search, Greedy
Medium
23
0.6%
770Disconnect Path in a Binary Matrix by at Most One Flip
Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Matrix
Medium
23
0.3%
771Check if There is a Path With Equal Number of 0's And 1's
Array, Dynamic Programming, Matrix
Medium
23
0.5%
772Count the Number of Fair Pairs
Array, Two Pointers, Binary Search, Sorting
Medium
23
0.5%
773Prime Subtraction Operation
Array, Math, Binary Search, Greedy, Number Theory
Medium
23
0.6%
774Find the Largest Area of Square Inside Two Rectangles
Array, Math, Geometry
Medium
23
0.7%
775Confirmation Rate
Database
Medium
23
0.6%
776Delete Duplicate Emails
Database
Easy
23
0.7%
777Binary Tree Longest Consecutive Sequence
Tree, Depth-First Search, Binary Tree
Medium
23
0.5%
778Smallest Rectangle Enclosing Black Pixels
Array, Binary Search, Depth-First Search, Breadth-First Search, Matrix
Hard
23
0.6%
779Patching Array
Array, Greedy
Hard
23
0.5%
780Count Subarrays With Score Less Than K
Array, Binary Search, Sliding Window, Prefix Sum
Hard
23
0.6%
781Evaluate Boolean Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
23
0.8%
782License Key Formatting
String
Easy
23
0.5%
783Maximum Sum of Distinct Subarrays With Length K
Array, Hash Table, Sliding Window
Medium
23
0.4%
784Redundant Connection II
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
23
0.4%
785Construct Binary Search Tree from Preorder Traversal
Array, Stack, Tree, Binary Search Tree, Monotonic Stack, Binary Tree
Medium
23
0.8%
786Parallel Courses
Graph Theory, Topological Sort
Medium
23
0.6%
787N-th Tribonacci Number
Math, Dynamic Programming, Memoization
Easy
23
0.6%
788Search Suggestions System
Array, String, Binary Search, Trie, Sorting, Heap (Priority Queue)
Medium
23
0.7%
789Clear Digits
String, Stack, Simulation
Easy
23
0.8%
790Avoid Flood in The City
Array, Hash Table, Binary Search, Greedy, Heap (Priority Queue)
Medium
23
0.4%
791Car Fleet II
Array, Math, Stack, Heap (Priority Queue), Monotonic Stack
Hard
23
0.6%
792Remove All Occurrences of a Substring
String, Stack, Simulation
Medium
23
0.8%
793Convert Object to JSON StringMedium
23
0.8%
794Number of Same-End Substrings
Array, Hash Table, String, Counting, Prefix Sum
Medium
23
0.6%
795Smallest Range Covering Elements from K Lists
Array, Hash Table, Greedy, Sliding Window, Sorting, Heap (Priority Queue)
Hard
23
0.7%
796Number of Ways to Arrive at Destination
Dynamic Programming, Graph Theory, Topological Sort, Shortest Path
Medium
23
0.4%
797Check if DFS Strings Are Palindromes
Array, Hash Table, String, Tree, Depth-First Search, Hash Function
Hard
23
0.2%
798Adjacent Increasing Subarrays Detection II
Array, Binary Search
Medium
23
0.6%
799Percentage of Users Attended a Contest
Database
Easy
23
0.6%
800Two Best Non-Overlapping Events
Array, Binary Search, Dynamic Programming, Sorting, Heap (Priority Queue)
Medium
23
0.6%
801House Robber IV
Array, Binary Search, Dynamic Programming, Greedy
Medium
23
0.6%
802Reschedule Meetings for Maximum Free Time II
Array, Greedy, Enumeration
Medium
23
0.6%
803The k-th Lexicographical String of All Happy Strings of Length n
String, Backtracking
Medium
23
0.9%
804Check if Number is a Sum of Powers of Three
Math
Medium
23
0.8%
805Find Minimum in Rotated Sorted Array II
Array, Binary Search
Hard
22
0.5%
806Read N Characters Given read4 II - Call Multiple Times
Array, Simulation, Interactive
Hard
22
0.4%
807Longest Substring with At Most Two Distinct Characters
Hash Table, String, Sliding Window
Medium
22
0.6%
808Bulb Switcher
Math, Brainteaser
Medium
22
0.6%
809Design Snake Game
Array, Hash Table, Design, Queue, Simulation
Medium
22
0.4%
810Line Reflection
Array, Hash Table, Math
Medium
22
0.4%
811Range Addition
Array, Prefix Sum
Medium
22
0.7%
812Smallest Good Base
Math, Binary Search
Hard
22
0.5%
813Max Consecutive Ones II
Array, Dynamic Programming, Sliding Window
Medium
22
0.5%
814All Paths from Source Lead to Destination
Graph Theory, Topological Sort
Medium
22
0.4%
815Freedom Trail
String, Dynamic Programming, Depth-First Search, Breadth-First Search
Hard
22
0.6%
816Design Compressed String Iterator
Array, String, Design, Iterator
Easy
22
0.4%
817Minimum Window Subsequence
String, Dynamic Programming, Sliding Window
Hard
22
0.4%
818My Calendar III
Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set
Hard
22
0.7%
819Sentence Similarity
Array, Hash Table, String
Easy
22
0.4%
820Insert into a Binary Search Tree
Tree, Binary Search Tree, Binary Tree
Medium
22
0.7%
821Search in a Sorted Array of Unknown Size
Array, Binary Search, Interactive
Medium
22
0.7%
822Minimum Distance Between BST Nodes
Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
22
0.6%
823Largest Sum of Averages
Array, Dynamic Programming, Prefix Sum
Medium
22
0.6%
824Linked List Components
Array, Hash Table, Linked List
Medium
22
0.6%
825K-Similar Strings
Hash Table, String, Breadth-First Search
Hard
22
0.4%
826Minimum Cost to Hire K Workers
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
22
0.6%
827Delete Columns to Make Sorted III
Array, String, Dynamic Programming
Hard
22
0.7%
828Numbers With Repeated Digits
Math, Dynamic Programming
Hard
22
0.5%
829Best Sightseeing Pair
Array, Dynamic Programming
Medium
22
0.6%
830Binary String With Substrings Representing 1 To N
Hash Table, String, Bit Manipulation, Sliding Window
Medium
22
0.6%
831Confusing Number
Math
Easy
22
0.5%
832Valid Boomerang
Array, Math, Geometry
Easy
22
0.4%
833Single-Row Keyboard
Hash Table, String
Easy
22
0.9%
834Smallest Subsequence of Distinct Characters
String, Stack, Greedy, Monotonic Stack
Medium
22
0.6%
835Minimum Falling Path Sum II
Array, Dynamic Programming, Matrix
Hard
22
0.6%
836Sum of Mutated Array Closest to Target
Array, Binary Search, Sorting
Medium
22
0.5%
837Alphabet Board Path
Hash Table, String
Medium
22
0.5%
838Deepest Leaves Sum
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
22
0.9%
839Pizza With 3n Slices
Array, Dynamic Programming, Greedy, Heap (Priority Queue)
Hard
22
0.5%
840Max Value of Equation
Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
Hard
22
0.5%
841Last Moment Before All Ants Fall Out of a Plank
Array, Brainteaser, Simulation
Medium
22
0.7%
842Maximum Non Negative Product in a Matrix
Array, Dynamic Programming, Matrix
Medium
22
0.5%
843Minimum Adjacent Swaps for K Consecutive Ones
Array, Greedy, Sliding Window, Prefix Sum
Hard
22
0.4%
844Number of Restricted Paths From First to Last Node
Dynamic Programming, Graph Theory, Topological Sort, Heap (Priority Queue), Shortest Path
Medium
22
0.4%
845Queries on Number of Points Inside a Circle
Array, Math, Geometry
Medium
22
0.9%
846Largest Color Value in a Directed Graph
Hash Table, String, Dynamic Programming, Graph Theory, Topological Sort, Memoization, Counting
Hard
22
0.6%
847Merge Triplets to Form Target Triplet
Array, Greedy
Medium
22
0.7%
848Number of Wonderful Substrings
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
22
0.7%
849Cutting Ribbons
Array, Binary Search
Medium
22
0.5%
850Count Fertile Pyramids in a Land
Array, Dynamic Programming, Matrix
Hard
22
0.7%
851Create Binary Tree From Descriptions
Array, Hash Table, Tree, Binary Tree
Medium
22
0.8%
852Most Frequent Number Following Key In an Array
Array, Hash Table, Counting
Easy
22
0.6%
853Check if Number Has Equal Digit Count and Digit Value
Hash Table, String, Counting
Easy
22
0.7%
854Longest Binary Subsequence Less Than or Equal to K
String, Dynamic Programming, Greedy, Memoization
Medium
22
0.5%
855Sum of Prefix Scores of Strings
Array, String, Trie, Counting
Hard
22
0.6%
856Determine if Two Events Have Conflict
Array, String
Easy
22
0.5%
857Find the Punishment Number of an Integer
Math, Backtracking
Medium
22
0.8%
858String Transformation
Math, String, Dynamic Programming, String Matching
Hard
22
0.3%
859Maximum Number That Sum of the Prices Is Less Than or Equal to K
Math, Binary Search, Dynamic Programming, Bit Manipulation
Medium
22
0.4%
860Find the Number of Ways to Place People II
Array, Math, Geometry, Sorting, Enumeration
Hard
22
0.6%
861Longest Common Suffix Queries
Array, String, Trie
Hard
22
0.5%
862Restore IP Addresses
String, Backtracking
Medium
22
0.6%
863Unique Binary Search Trees
Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree
Medium
22
0.6%
864Construct Binary Tree from Inorder and Postorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
22
0.7%
865Repeated DNA Sequences
Hash Table, String, Bit Manipulation, Sliding Window, Rolling Hash, Hash Function
Medium
22
0.5%
866Closest Binary Search Tree Value
Binary Search, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
22
0.5%
867Minimum Consecutive Cards to Pick Up
Array, Hash Table, Sliding Window
Medium
22
0.5%
868Water and Jug Problem
Math, Depth-First Search, Breadth-First Search
Medium
22
0.5%
869Guess Number Higher or Lower II
Math, Dynamic Programming, Game Theory
Medium
22
0.5%
870Longest Nice Subarray
Array, Bit Manipulation, Sliding Window
Medium
22
0.6%
871Number of Boomerangs
Array, Hash Table, Math
Medium
22
0.6%
872Longest Uncommon Subsequence II
Array, Hash Table, Two Pointers, String, Sorting
Medium
22
0.5%
873Beautiful Arrangement
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
22
0.6%
874Not Boring Movies
Database
Easy
22
0.8%
875Split Array into Consecutive Subsequences
Array, Hash Table, Greedy, Heap (Priority Queue)
Medium
22
0.5%
876Couples Holding Hands
Greedy, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
22
0.6%
877Reaching Points
Math
Hard
22
0.3%
878Shortest Path to Get All Keys
Array, Bit Manipulation, Breadth-First Search, Matrix
Hard
22
0.5%
879Reverse Only Letters
Two Pointers, String
Easy
22
0.7%
880Critical Connections in a Network
Depth-First Search, Graph Theory, Biconnected Component
Hard
22
0.6%
881All Ancestors of a Node in a Directed Acyclic Graph
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
22
0.6%
882The Number of Employees Which Report to Each Employee
Database
Easy
22
0.5%
883Spiral Matrix III
Array, Matrix, Simulation
Medium
22
0.8%
884Return Length of Arguments PassedEasy
22
0.9%
885Stone Game
Array, Math, Dynamic Programming, Game Theory
Medium
22
0.7%
886Largest Odd Number in String
Math, String, Greedy
Easy
22
0.7%
887Maximum Employees to Be Invited to a Meeting
Array, Dynamic Programming, Depth-First Search, Graph Theory, Topological Sort
Hard
22
0.6%
888Maximum Matrix Sum
Array, Greedy, Matrix
Medium
22
0.7%
889Design Twitter
Hash Table, Linked List, Design, Heap (Priority Queue)
Medium
22
0.4%
890Design Task Manager
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
22
0.5%
891Partition Array According to Given Pivot
Array, Two Pointers, Simulation
Medium
22
0.9%
892Longest Palindromic Subsequence After at Most K Operations
String, Dynamic Programming
Medium
22
0.4%
893Find the K-th Character in String Game I
Math, Bit Manipulation, Recursion, Simulation
Easy
22
0.8%
894Solving Questions With Brainpower
Array, Dynamic Programming
Medium
22
0.6%
895Palindrome Partitioning II
String, Dynamic Programming
Hard
22
0.4%
896Maximum Erasure Value
Array, Hash Table, Sliding Window
Medium
22
0.6%
897Divide an Array Into Subarrays With Minimum Cost I
Array, Sorting, Enumeration
Easy
22
0.8%
898Longest Balanced Subarray II
Array, Hash Table, Divide and Conquer, Segment Tree, Prefix Sum
Hard
22
0.3%
899Minimum Depth of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
21
0.5%
900Binary Tree Postorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
21
0.8%
901Strobogrammatic Number
Hash Table, Two Pointers, String
Easy
21
0.5%
902Flatten 2D Vector
Array, Two Pointers, Design, Iterator
Medium
21
0.5%
903Closest Binary Search Tree Value II
Two Pointers, Stack, Tree, Depth-First Search, Binary Search Tree, Heap (Priority Queue), Binary Tree
Hard
21
0.6%
904Zigzag Iterator
Array, Design, Queue, Iterator
Medium
21
0.7%
905Peeking Iterator
Array, Design, Iterator
Medium
21
0.6%
906Super Ugly Number
Array, Math, Dynamic Programming
Medium
21
0.5%
907Longest Substring with At Most K Distinct Characters
Hash Table, String, Sliding Window
Medium
21
0.5%
908Design Tic-Tac-Toe
Array, Hash Table, Design, Matrix, Simulation
Medium
21
0.6%
909Plus One Linked List
Linked List, Math
Medium
21
0.6%
910The Maze II
Array, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
21
0.6%
911Word Abbreviation
Array, String, Greedy, Trie, Sorting
Hard
21
0.6%
912Output Contest Matches
String, Recursion, Simulation
Medium
21
0.8%
913Boundary of Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
21
0.5%
914Longest Line of Consecutive One in Matrix
Array, Dynamic Programming, Matrix
Medium
21
0.5%
915Subtree of Another Tree
Tree, Depth-First Search, String Matching, Binary Tree, Hash Function
Easy
21
0.5%
916Shopping Offers
Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
Medium
21
0.5%
917Beautiful Arrangement II
Array, Math
Medium
21
0.6%
918Kth Smallest Number in Multiplication Table
Math, Binary Search
Hard
21
0.5%
919K Empty Slots
Array, Binary Indexed Tree, Segment Tree, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Hard
21
0.4%
920Shortest Completing Word
Array, Hash Table, String
Easy
21
0.6%
921Find Anagram Mappings
Array, Hash Table
Easy
21
0.8%
922Basic Calculator III
Math, String, Stack, Recursion
Hard
21
0.5%
923Bricks Falling When Hit
Array, Union-Find, Matrix
Hard
21
0.4%
924Super Palindromes
Math, String, Enumeration
Hard
21
0.4%
925Divisor Game
Math, Dynamic Programming, Brainteaser, Game Theory
Easy
21
0.7%
926Minimum Cost to Connect Sticks
Array, Greedy, Heap (Priority Queue)
Medium
21
0.7%
927Product Sales Analysis I
Database
Easy
21
0.9%
928Brace Expansion II
Hash Table, String, Backtracking, Stack, Breadth-First Search, Sorting
Hard
21
0.6%
929Divide Chocolate
Array, Binary Search
Hard
21
0.6%
930Mean of Array After Removing Some Elements
Array, Sorting
Easy
21
0.7%
931Element Appearing More Than 25% In Sorted Array
Array
Easy
21
0.6%
932Distinct Echo Substrings
String, Trie, Rolling Hash, Hash Function
Hard
21
0.5%
933Decrease Elements To Make Array Zigzag
Array, Greedy
Medium
21
0.5%
934Binary Tree Coloring Game
Tree, Depth-First Search, Binary Tree
Medium
21
0.5%
935Longest Chunked Palindrome Decomposition
Two Pointers, String, Dynamic Programming, Greedy, Rolling Hash, Hash Function
Hard
21
0.6%
936Where Will the Ball Fall
Array, Matrix, Simulation
Medium
21
0.7%
937Maximum Value of K Coins From Piles
Array, Dynamic Programming, Prefix Sum
Hard
21
0.6%
938Number of Ways to Stay in the Same Place After Some Steps
Dynamic Programming
Hard
21
0.5%
939Longest Happy Prefix
String, Rolling Hash, String Matching, Hash Function
Hard
21
0.5%
940Find the Minimum Number of Fibonacci Numbers Whose Sum Is K
Math, Greedy
Medium
21
0.6%
941Simplified Fractions
Math, String, Number Theory
Medium
21
0.7%
942Find Two Non-overlapping Sub-arrays Each With Target Sum
Array, Hash Table, Binary Search, Dynamic Programming, Sliding Window
Medium
21
0.4%
943Find Root of N-Ary Tree
Hash Table, Bit Manipulation, Tree, Depth-First Search
Medium
21
0.8%
944Number of Good Leaf Nodes Pairs
Tree, Depth-First Search, Binary Tree
Medium
21
0.7%
945Number of Ways to Reorder Array to Get Same BST
Array, Math, Divide and Conquer, Dynamic Programming, Tree, Union-Find, Binary Search Tree, Memoization, Combinatorics, Binary Tree
Hard
21
0.5%
946Strange Printer II
Array, Graph Theory, Topological Sort, Matrix
Hard
21
0.6%
947Rearrange Spaces Between Words
String
Easy
21
0.4%
948Minimum Cost to Connect Two Groups of Points
Array, Dynamic Programming, Bit Manipulation, Matrix, Bitmask
Hard
21
0.5%
949Throne Inheritance
Hash Table, Tree, Depth-First Search, Design
Medium
21
0.7%
950Fancy Sequence
Math, Design, Segment Tree, Number Theory
Hard
21
0.4%
951Distribute Repeating Integers
Array, Hash Table, Dynamic Programming, Backtracking, Bit Manipulation, Counting, Bitmask
Hard
21
0.4%
952Max Number of K-Sum Pairs
Array, Hash Table, Two Pointers, Sorting
Medium
21
0.6%
953Minimum Operations to Make a Subsequence
Array, Hash Table, Binary Search, Greedy
Hard
21
0.5%
954Find Kth Largest XOR Coordinate Value
Array, Divide and Conquer, Bit Manipulation, Sorting, Heap (Priority Queue), Matrix, Prefix Sum, Quickselect
Medium
21
0.6%
955Maximum Score from Performing Multiplication Operations
Array, Dynamic Programming
Hard
21
0.4%
956Design Most Recently Used Queue
Array, Linked List, Divide and Conquer, Design, Simulation, Doubly-Linked List
Medium
21
0.8%
957Maximum Number of Groups Getting Fresh Donuts
Array, Dynamic Programming, Bit Manipulation, Memoization, Bitmask
Hard
21
0.4%
958Minimum Path Cost in a Hidden Grid
Array, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Interactive, Shortest Path
Medium
21
0.6%
959Kth Smallest Subarray Sum
Array, Binary Search, Sliding Window
Medium
21
0.5%
960Last Day Where You Can Still Cross
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Hard
21
0.7%
961Operations on Tree
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search, Design
Medium
21
0.5%
962Binary Searchable Numbers in an Unsorted Array
Array, Binary Search, Stack, Monotonic Stack
Medium
21
0.6%
963Final Value of Variable After Performing Operations
Array, String, Simulation
Easy
21
0.9%
964Minimum Operations to Convert Number
Array, Breadth-First Search
Medium
21
0.5%
965Minimum Cost to Set Cooking Time
Math, Enumeration
Medium
21
0.4%
966Find All Lonely Numbers in the Array
Array, Hash Table, Counting
Medium
21
0.6%
967Maximum Split of Positive Even Integers
Math, Backtracking, Greedy
Medium
21
0.6%
968Minimum Time to Remove All Cars Containing Illegal Goods
String, Dynamic Programming
Hard
21
0.4%
969Maximum AND Sum of Array
Array, Dynamic Programming, Bit Manipulation, Bitmask
Hard
21
0.5%
970Count Prefixes of a Given String
Array, String
Easy
21
0.7%
971Count Asterisks
String
Easy
21
0.8%
972Merge Similar Items
Array, Hash Table, Sorting, Ordered Set
Easy
21
0.8%
973Finding the Number of Visible Mountains
Array, Stack, Sorting, Monotonic Stack
Medium
21
0.4%
974Longest Uploaded Prefix
Hash Table, Binary Search, Union-Find, Design, Binary Indexed Tree, Segment Tree, Heap (Priority Queue), Ordered Set
Medium
21
0.6%
975Number of Pairs Satisfying Inequality
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
21
0.5%
976Number of Beautiful Partitions
String, Dynamic Programming, Prefix Sum
Hard
21
0.3%
977Make Number of Distinct Characters Equal
Hash Table, String, Counting
Medium
21
0.3%
978Increment Submatrices by One
Array, Matrix, Prefix Sum
Medium
21
0.7%
979SleepEasy
21
0.9%
980Sum of Imbalance Numbers of All Subarrays
Array, Hash Table, Enumeration
Hard
21
0.4%
981Minimum Absolute Difference Between Elements With Constraint
Array, Binary Search, Ordered Set
Medium
21
0.4%
982Count K-Subsequences of a String With Maximum Beauty
Hash Table, Math, String, Greedy, Sorting, Combinatorics
Hard
21
0.3%
983Find Champion II
Graph Theory
Medium
21
0.7%
984Find Longest Special Substring That Occurs Thrice II
Hash Table, String, Binary Search, Sliding Window, Counting
Medium
21
0.4%
985Minimum Number of Operations to Make Word K-Periodic
Hash Table, String, Counting
Medium
21
0.6%
986Sum of Digit Differences of All Pairs
Array, Hash Table, Math, Counting
Medium
21
0.4%
987Sum of Subarray Ranges
Array, Stack, Monotonic Stack
Medium
21
0.6%
988Strobogrammatic Number II
Array, String, Recursion
Medium
21
0.5%
989Meeting Rooms
Array, Sorting
Easy
21
0.6%
990Design Phone Directory
Array, Hash Table, Linked List, Design, Queue
Medium
21
0.5%
991Longest Substring with At Least K Repeating Characters
Hash Table, String, Divide and Conquer, Sliding Window
Medium
21
0.5%
992Number of Valid Clock Times
String, Enumeration
Easy
21
0.5%
993Erect the Fence
Array, Math, Geometry
Hard
21
0.5%
994Add Bold Tag in String
Array, Hash Table, String, Trie, String Matching
Medium
21
0.5%
995Search in a Binary Search Tree
Tree, Binary Search Tree, Binary Tree
Easy
21
0.8%
996Hand of Straights
Array, Hash Table, Greedy, Sorting
Medium
21
0.6%
997Profitable Schemes
Array, Dynamic Programming
Hard
21
0.5%
998Super Egg Drop
Math, Binary Search, Dynamic Programming
Hard
21
0.3%
999Distribute Coins in Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
21
0.8%
1000Maximum Length of Semi-Decreasing Subarrays
Array, Stack, Sorting, Monotonic Stack
Medium
21
0.7%
1001Last Stone Weight
Array, Heap (Priority Queue)
Easy
21
0.7%
1002Parsing A Boolean Expression
String, Stack, Recursion
Hard
21
0.7%
1003Convert Binary Number in a Linked List to Integer
Linked List, Math
Easy
21
0.8%
1004Find Valid Matrix Given Row and Column Sums
Array, Greedy, Matrix
Medium
21
0.8%
1005Split Two Strings to Make Palindrome
Two Pointers, String
Medium
21
0.3%
1006Number of Students Unable to Eat Lunch
Array, Stack, Queue, Simulation
Easy
21
0.8%
1007Replace All Digits with Characters
String
Easy
21
0.8%
1008Swapping Nodes in a Linked List
Linked List, Two Pointers
Medium
21
0.7%
1009Find the Maximum Number of Elements in Subset
Array, Hash Table, Enumeration
Medium
21
0.3%
1010Alternating Groups II
Array, Sliding Window
Medium
21
0.6%
1011Finding 3-Digit Even Numbers
Array, Hash Table, Recursion, Sorting, Enumeration
Easy
21
0.8%
1012Self Dividing Numbers
Math
Easy
21
0.8%
1013Separate Squares II
Array, Binary Search, Segment Tree, Sweep Line
Hard
21
0.6%
1014Number of Equivalent Domino Pairs
Array, Hash Table, Counting
Easy
21
0.6%
1015Maximize Subarray GCD Score
Array, Math, Enumeration, Number Theory
Hard
21
0.3%
1016Partition String
Hash Table, String, Trie, Simulation
Medium
21
0.6%
1017Left and Right Sum Differences
Array, Prefix Sum
Easy
21
0.9%
1018Fruits Into Baskets II
Array, Binary Search, Segment Tree, Simulation, Ordered Set
Easy
21
0.7%
1019Reordered Power of 2
Hash Table, Math, Sorting, Counting, Enumeration
Medium
21
0.7%
1020Minimum Cost Path with Edge Reversals
Graph Theory, Heap (Priority Queue), Shortest Path
Medium
21
0.6%
1021N-Queens II
Backtracking
Hard
20
0.8%
1022Scramble String
String, Dynamic Programming
Hard
20
0.4%
1023Palindrome Permutation
Hash Table, String, Bit Manipulation
Easy
20
0.7%
1024Unique Word Abbreviation
Array, Hash Table, String, Design
Medium
20
0.3%
1025Flip Game
String
Easy
20
0.7%
1026Flip Game II
Math, Dynamic Programming, Backtracking, Memoization, Game Theory
Medium
20
0.5%
1027Generalized Abbreviation
String, Backtracking, Bit Manipulation
Medium
20
0.6%
1028Bomb Enemy
Array, Dynamic Programming, Matrix
Medium
20
0.5%
1029Minimum Unique Word Abbreviation
Array, String, Backtracking, Bit Manipulation
Hard
20
0.4%
1030Valid Word Square
Array, Matrix
Easy
20
0.4%
1031Word Squares
Array, String, Backtracking, Trie
Hard
20
0.5%
1032Convex Polygon
Array, Math, Geometry
Medium
20
0.4%
1033Encode String with Shortest Length
String, Dynamic Programming
Hard
20
0.5%
1034Find Permutation
Array, String, Stack, Greedy
Medium
20
0.7%
1035Count Subarrays With More Ones Than Zeros
Array, Hash Table, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Medium
20
0.5%
1036Longest Uncommon Subsequence I
String
Easy
20
0.6%
1037Lonely Pixel I
Array, Hash Table, Matrix
Medium
20
0.6%
1038Lonely Pixel II
Array, Hash Table, Matrix
Medium
20
0.5%
1039Binary Tree Longest Consecutive Sequence II
Tree, Depth-First Search, Binary Tree
Medium
20
0.5%
1040Maximum Vacation Days
Array, Dynamic Programming, Matrix
Hard
20
0.5%
1041Median Employee Salary
Database
Hard
20
0.7%
1042Maximum Average Subarray II
Array, Binary Search, Prefix Sum
Hard
20
0.4%
10434 Keys Keyboard
Math, Dynamic Programming
Medium
20
0.6%
1044Coin Path
Array, Dynamic Programming
Hard
20
0.3%
1045Number of Longest Increasing Subsequence
Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
Medium
20
0.5%
1046Baseball Game
Array, Stack, Simulation
Easy
20
0.8%
1047Longest Univalue Path
Tree, Depth-First Search, Binary Tree
Medium
20
0.4%
1048Bold Words in String
Array, Hash Table, String, Trie, String Matching
Medium
20
0.5%
1049Flatten a Multilevel Doubly Linked List
Linked List, Depth-First Search, Doubly-Linked List
Medium
20
0.6%
1050Transform to Chessboard
Array, Math, Bit Manipulation, Matrix
Hard
20
0.5%
1051Similar RGB Color
Math, String, Enumeration
Easy
20
0.7%
1052Ambiguous Coordinates
String, Backtracking, Enumeration
Medium
20
0.6%
1053Positions of Large Groups
String
Easy
20
0.5%
1054Random Pick with Blacklist
Array, Hash Table, Math, Binary Search, Sorting, Randomized
Hard
20
0.4%
1055Random Flip Matrix
Hash Table, Math, Reservoir Sampling, Randomized
Medium
20
0.5%
1056Complete Binary Tree Inserter
Tree, Breadth-First Search, Design, Binary Tree
Medium
20
0.7%
1057Array of Doubled Pairs
Array, Hash Table, Greedy, Sorting
Medium
20
0.4%
1058Find the Town Judge
Array, Hash Table, Graph Theory
Easy
20
0.5%
1059Shortest Way to Form String
Two Pointers, String, Binary Search, Greedy
Medium
20
0.6%
1060Campus Bikes II
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
20
0.6%
1061Brace Expansion
String, Backtracking, Stack, Breadth-First Search, Sorting
Medium
20
0.7%
1062Confusing Number II
Math, Backtracking
Hard
20
0.5%
1063Camelcase Matching
Array, Two Pointers, String, Trie, String Matching
Medium
20
0.7%
1064Divide Array Into Increasing Sequences
Array, Counting
Hard
20
0.7%
1065Partition Array for Maximum Sum
Array, Dynamic Programming
Medium
20
0.8%
1066String Transforms Into Another String
Hash Table, String, Graph Theory
Hard
20
0.3%
1067Shortest Distance to Target Color
Array, Binary Search, Dynamic Programming
Medium
20
0.6%
1068Optimize Water Distribution in a Village
Union-Find, Graph Theory, Heap (Priority Queue), Minimum Spanning Tree
Hard
20
0.7%
1069Occurrences After Bigram
String
Easy
20
0.6%
1070Minimum Time to Build Blocks
Array, Math, Greedy, Heap (Priority Queue)
Hard
20
0.5%
1071Largest Values From Labels
Array, Hash Table, Greedy, Sorting, Counting
Medium
20
0.6%
1072Tree Diameter
Tree, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
20
0.6%
1073Iterator for Combination
String, Backtracking, Design, Iterator
Medium
20
0.7%
1074Compare Strings by Frequency of the Smallest Character
Array, Hash Table, String, Binary Search, Sorting
Medium
20
0.6%
1075Distance Between Bus Stops
Array
Easy
20
0.6%
1076Design Skiplist
Linked List, Design
Hard
20
0.6%
1077Maximum Font to Fit a Sentence in a Screen
Array, String, Binary Search, Interactive
Medium
20
0.6%
1078Find Elements in a Contaminated Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree
Medium
20
0.8%
1079Minimum Path Cost in a Grid
Array, Dynamic Programming, Matrix
Medium
20
0.7%
1080All People Report to the Given Manager
Database
Medium
20
0.8%
1081Count Negative Numbers in a Sorted Matrix
Array, Binary Search, Matrix
Easy
20
0.8%
1082Circle and Rectangle Overlapping
Math, Geometry
Medium
20
0.5%
1083Diagonal Traverse II
Array, Sorting, Heap (Priority Queue)
Medium
20
0.6%
1084Form Largest Integer With Digits That Add up to Target
Array, Dynamic Programming
Hard
20
0.5%
1085People Whose List of Favorite Companies Is Not a Subset of Another List
Array, Hash Table, String
Medium
20
0.6%
1086The k Strongest Values in an Array
Array, Two Pointers, Sorting
Medium
20
0.6%
1087Number of Substrings With Only 1s
Math, String
Medium
20
0.6%
1088Maximum Number of Non-Overlapping Subarrays With Sum Equals Target
Array, Hash Table, Greedy, Prefix Sum
Medium
20
0.5%
1089Move Sub-Tree of N-Ary Tree
Tree, Depth-First Search
Hard
20
0.6%
1090Guess the Majority in a Hidden Array
Array, Math, Interactive
Medium
20
0.7%
1091Find Latest Group of Size M
Array, Hash Table, Binary Search, Simulation
Medium
20
0.4%
1092The Most Similar Path in a Graph
Array, String, Dynamic Programming, Graph Theory
Hard
20
0.6%
1093Put Boxes Into the Warehouse I
Array, Greedy, Sorting
Medium
20
0.7%
1094Check If String Is Transformable With Substring Sort Operations
String, Greedy, Sorting
Hard
20
0.5%
1095Put Boxes Into the Warehouse II
Array, Greedy, Sorting
Medium
20
0.7%
1096Number of Ways to Form a Target String Given a Dictionary
Array, String, Dynamic Programming
Hard
20
0.6%
1097Find Nearest Right Node in Binary Tree
Tree, Breadth-First Search, Binary Tree
Medium
20
0.8%
1098Check If Two Expression Trees are Equivalent
Hash Table, Tree, Depth-First Search, Binary Tree, Counting
Medium
20
0.7%
1099Correct a Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
20
0.7%
1100Change the Root of a Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
20
0.7%
1101Count Ways to Distribute Candies
Dynamic Programming
Hard
20
0.6%
1102Largest Subarray Length K
Array, Greedy
Easy
20
0.7%
1103Change Minimum Characters to Satisfy One of Three Conditions
Hash Table, String, Counting, Prefix Sum
Medium
20
0.4%
1104Checking Existence of Edge Length Limited Paths II
Depth-First Search, Union-Find, Graph Theory, Design, Sorting, Heap (Priority Queue), Minimum Spanning Tree
Hard
20
0.5%
1105Tree of Coprimes
Array, Math, Tree, Depth-First Search, Number Theory
Hard
20
0.4%
1106Maximum Score From Removing Stones
Math, Greedy, Heap (Priority Queue)
Medium
20
0.7%
1107Closest Dessert Cost
Array, Dynamic Programming, Backtracking
Medium
20
0.5%
1108Find the Subtasks That Did Not Execute
Database
Hard
20
0.8%
1109Minimum Number of Operations to Reinitialize a Permutation
Array, Math, Simulation
Medium
20
0.7%
1110Count Pairs of Equal Substrings With Minimum Difference
Hash Table, String, Greedy
Medium
20
0.6%
1111Find Customers With Positive Revenue this Year
Database
Easy
20
0.9%
1112Minimum Adjacent Swaps to Reach the Kth Smallest Number
Two Pointers, String, Greedy
Medium
20
0.7%
1113Number of Ways to Rearrange Sticks With K Sticks Visible
Math, Dynamic Programming, Combinatorics
Hard
20
0.6%
1114Minimum Speed to Arrive on Time
Array, Binary Search
Medium
20
0.5%
1115Minimum Cost to Change the Final Value of Expression
Math, String, Dynamic Programming, Stack
Hard
20
0.5%
1116Longest Word With All Prefixes
Array, String, Depth-First Search, Trie
Medium
20
0.7%
1117Minimum Skips to Arrive at Meeting On Time
Array, Dynamic Programming
Hard
20
0.4%
1118Minimize Product Sum of Two Arrays
Array, Greedy, Sorting
Medium
20
0.9%
1119Minimum Absolute Difference Queries
Array, Prefix Sum
Medium
20
0.5%
1120Find a Peak Element II
Array, Binary Search, Matrix
Medium
20
0.6%
1121Longest Common Subsequence Between Sorted Arrays
Array, Hash Table, Counting
Medium
20
0.8%
1122Erect the Fence II
Array, Math, Geometry
Hard
20
0.5%
1123Process Restricted Friend Requests
Union-Find, Graph Theory
Hard
20
0.6%
1124Paths in Maze That Lead to Same Room
Graph Theory
Medium
20
0.6%
1125Watering Plants II
Array, Two Pointers, Simulation
Medium
20
0.5%
1126Recover the Original Array
Array, Hash Table, Two Pointers, Sorting, Enumeration
Hard
20
0.4%
1127Count Words Obtained After Adding a Letter
Array, Hash Table, String, Bit Manipulation, Sorting
Medium
20
0.4%
1128All Divisions With the Highest Score of a Binary Array
Array
Medium
20
0.7%
1129Remove All Ones With Row and Column Flips
Array, Math, Bit Manipulation, Matrix
Medium
20
0.8%
1130Minimum White Tiles After Covering With Carpets
String, Dynamic Programming, Prefix Sum
Hard
20
0.4%
1131Remove All Ones With Row and Column Flips II
Array, Bit Manipulation, Breadth-First Search, Matrix
Medium
20
0.7%
1132Minimum Number of Operations to Convert Time
String, Greedy
Easy
20
0.7%
1133Check if There Is a Valid Parentheses String Path
Array, Dynamic Programming, Matrix
Hard
20
0.4%
1134Design an ATM Machine
Array, Greedy, Design
Medium
20
0.5%
1135Maximum White Tiles Covered by a Carpet
Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
Medium
20
0.4%
1136Minimum Lines to Represent a Line Chart
Array, Math, Geometry, Sorting, Number Theory
Medium
20
0.3%
1137Booking Concert Tickets in Groups
Binary Search, Design, Binary Indexed Tree, Segment Tree
Hard
20
0.2%
1138Count Positions on Street With Required Brightness
Array, Prefix Sum
Medium
20
0.6%
1139Design Video Sharing Platform
Hash Table, Design, Heap (Priority Queue)
Hard
20
0.6%
1140Minimum Flips in Binary Tree to Get Result
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
20
0.6%
1141Subarray With Elements Greater Than Varying Threshold
Array, Stack, Union-Find, Monotonic Stack
Hard
20
0.5%
1142Shortest Impossible Sequence of Rolls
Array, Hash Table, Greedy
Hard
20
0.7%
1143Sort Array by Moving Items to Empty Space
Array, Hash Table, Sorting
Hard
20
0.5%
1144Minimize Maximum Value in a Grid
Array, Union-Find, Graph Theory, Topological Sort, Sorting, Matrix
Hard
20
0.7%
1145Count Subarrays With Median K
Array, Hash Table, Prefix Sum
Hard
20
0.5%
1146Extract Kth Character From The Rope Tree
Tree, Depth-First Search, Binary Tree
Easy
20
0.7%
1147Count Houses in a Circular Street
Array, Interactive
Easy
20
0.9%
1148Count Pairs of Points With Distance k
Array, Hash Table, Bit Manipulation
Medium
20
0.3%
1149Determine if a Cell Is Reachable at a Given Time
Math
Medium
20
0.4%
1150Minimum Increment Operations to Make Array Beautiful
Array, Dynamic Programming
Medium
20
0.3%
1151Find Champion I
Array, Matrix
Easy
20
0.7%
1152Maximum Score After Applying Operations on a Tree
Dynamic Programming, Tree, Depth-First Search
Medium
20
0.5%
1153Count the Number of Good Partitions
Array, Hash Table, Math, Combinatorics
Hard
20
0.5%
1154Number of Equal Numbers Blocks
Array, Binary Search, Interactive
Medium
20
0.6%
1155Minimum Cost to Make Array Equalindromic
Array, Math, Binary Search, Greedy, Sorting
Medium
20
0.2%
1156Maximize Consecutive Elements in an Array After Modification
Array, Dynamic Programming, Sorting
Hard
20
0.3%
1157Most Frequent Prime
Array, Hash Table, Math, Matrix, Counting, Enumeration, Number Theory
Medium
20
0.5%
1158Latest Time You Can Obtain After Replacing Characters
String, Enumeration
Easy
20
0.4%
1159Minimum Sum of Values by Dividing Array
Array, Binary Search, Dynamic Programming, Bit Manipulation, Segment Tree, Queue
Hard
20
0.3%
1160Employees Whose Manager Left the Company
Database
Easy
20
0.5%
1161Path Sum II
Backtracking, Tree, Depth-First Search, Binary Tree
Medium
20
0.6%
1162Smallest Index With Equal Value
Array
Easy
20
0.7%
1163Time Needed to Buy Tickets
Array, Queue, Simulation
Easy
20
0.7%
1164Rings and Rods
Hash Table, String
Easy
20
0.8%
1165Valid Phone Numbers
Shell
Easy
20
0.3%
1166Different Ways to Add Parentheses
Math, String, Dynamic Programming, Recursion, Memoization
Medium
20
0.7%
1167Amount of New Area Painted Each Day
Array, Segment Tree, Ordered Set
Hard
20
0.6%
1168Integer Break
Math, Dynamic Programming
Medium
20
0.6%
1169Arranging Coins
Math, Binary Search
Easy
20
0.5%
1170K-diff Pairs in an Array
Array, Hash Table, Two Pointers, Binary Search, Sorting
Medium
20
0.5%
1171Minimize the Maximum Difference of Pairs
Array, Binary Search, Dynamic Programming, Greedy, Sorting
Medium
20
0.5%
1172Apply Transform Over Each Element in ArrayEasy
20
0.9%
1173Find the Maximum Achievable Number
Math
Easy
20
0.9%
1174Rabbits in Forest
Array, Hash Table, Math, Greedy
Medium
20
0.6%
1175Fair Candy Swap
Array, Hash Table, Binary Search, Sorting
Easy
20
0.7%
1176Range Sum of BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
20
0.9%
1177Reveal Cards In Increasing Order
Array, Queue, Sorting, Simulation
Medium
20
0.8%
1178Maximum Profit in Job Scheduling
Array, Binary Search, Dynamic Programming, Sorting
Hard
20
0.5%
1179Find Positive Integer Solution for a Given Equation
Math, Two Pointers, Binary Search, Interactive
Medium
20
0.7%
1180Maximize Total Cost of Alternating Subarrays
Array, Dynamic Programming
Medium
20
0.3%
1181Frog Position After T Seconds
Tree, Depth-First Search, Breadth-First Search, Graph Theory
Hard
20
0.4%
1182Shuffle String
Array, String
Easy
20
0.9%
1183Fix Names in a Table
Database
Easy
20
0.6%
1184Calculate Money in Leetcode Bank
Math
Easy
20
0.8%
1185Find the City With the Smallest Number of Neighbors at a Threshold Distance
Dynamic Programming, Graph Theory, Shortest Path
Medium
20
0.7%
1186Count the Number of Substrings With Dominant Ones
String, Enumeration
Medium
20
0.4%
1187Find Smallest Letter Greater Than Target
Array, Binary Search
Easy
20
0.6%
1188Final Prices With a Special Discount in a Shop
Array, Stack, Monotonic Stack
Easy
20
0.8%
1189Maximum Number of Operations to Move Ones to the End
String, Greedy, Counting
Medium
20
0.7%
1190Binary Tree Nodes
Database
Medium
20
0.8%
1191Corporate Flight Bookings
Array, Prefix Sum
Medium
20
0.7%
1192Calculate Compressed Mean
Database
Easy
20
0.9%
1193Top Three Wineries
Database
Hard
20
0.5%
1194Find Expensive Cities
Database
Easy
20
0.8%
1195Class Performance
Database
Medium
20
0.9%
1196Loan Types
Database
Easy
20
0.6%
1197Find Beautiful Indices in the Given Array II
Two Pointers, String, Binary Search, Rolling Hash, String Matching, Hash Function
Hard
20
0.3%
1198Ant on the Boundary
Array, Simulation, Prefix Sum
Easy
20
0.7%
1199Add Two Numbers II
Linked List, Math, Stack
Medium
20
0.6%
1200Lemonade Change
Array, Greedy
Easy
20
0.6%
1201Last Stone Weight II
Array, Dynamic Programming
Medium
20
0.6%
1202Defuse the Bomb
Array, Sliding Window
Easy
20
0.8%
1203Maximum Area Rectangle With Point Constraints I
Array, Math, Binary Indexed Tree, Segment Tree, Geometry, Sorting, Enumeration
Medium
20
0.5%
1204Minimum Absolute Difference
Array, Sorting
Easy
20
0.8%
1205Number of Ways to Split Array
Array, Prefix Sum
Medium
20
0.6%
1206Shifting Letters II
Array, String, Prefix Sum
Medium
20
0.5%
1207Perfect Number
Math
Easy
20
0.5%
1208Minimum Time to Repair Cars
Array, Binary Search
Medium
20
0.6%
1209Find the Minimum Amount of Time to Brew Potions
Array, Simulation, Prefix Sum
Medium
20
0.6%
1210Count Good Triplets
Array, Enumeration
Easy
20
0.9%
1211Find the Count of Monotonic Pairs I
Array, Math, Dynamic Programming, Combinatorics, Prefix Sum
Hard
20
0.5%
1212Kth Smallest Product of Two Sorted Arrays
Array, Binary Search
Hard
20
0.5%
1213Count Cells in Overlapping Horizontal and Vertical Substrings
Array, String, Rolling Hash, String Matching, Matrix, Hash Function
Medium
20
0.3%
1214Department Highest Salary
Database
Medium
20
0.6%
1215Number of Stable Subsequences
Array, Dynamic Programming
Hard
20
0.6%
1216Count Caesar Cipher Pairs
Array, Hash Table, Math, String, Counting
Medium
20
0.5%
1217Valid Number
String
Hard
18
0.2%
1218Insertion Sort List
Linked List, Sorting
Medium
18
0.6%
1219Bitwise AND of Numbers Range
Bit Manipulation
Medium
18
0.5%
1220Minimum Number of Arrows to Burst Balloons
Array, Greedy, Sorting
Medium
18
0.6%
1221Employee Importance
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
18
0.7%
1222Partition to K Equal Sum Subsets
Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
Medium
18
0.4%
1223Construct Quad Tree
Array, Divide and Conquer, Tree, Matrix
Medium
18
0.8%
1224Minimum Number of Refueling Stops
Array, Dynamic Programming, Greedy, Heap (Priority Queue)
Hard
18
0.4%
1225Complement of Base 10 Integer
Bit Manipulation
Easy
18
0.6%
1226Recover a Tree From Preorder Traversal
String, Tree, Depth-First Search, Binary Tree
Hard
18
0.8%
1227Number of Steps to Reduce a Number to Zero
Math, Bit Manipulation
Easy
18
0.9%
1228Min Cost to Connect All Points
Array, Union-Find, Graph Theory, Minimum Spanning Tree
Medium
18
0.7%
1229Maximum Number of Events That Can Be Attended II
Array, Binary Search, Dynamic Programming, Sorting
Hard
18
0.6%
1230Find Unique Binary String
Array, Hash Table, String, Backtracking
Medium
18
0.8%
1231Maximum Twin Sum of a Linked List
Linked List, Two Pointers, Stack
Medium
18
0.8%
1232Rectangle Area
Math, Geometry
Medium
18
0.5%
1233Single Number III
Array, Bit Manipulation
Medium
18
0.7%
1234Root Equals Sum of Children
Tree, Binary Tree
Easy
18
0.9%
1235Keyboard Row
Array, Hash Table, String
Easy
18
0.7%
1236Array Partition
Array, Greedy, Sorting, Counting Sort
Easy
18
0.8%
1237Maximum Subsequence Score
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
18
0.5%
1238Valid Triangle Number
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
18
0.6%
1239Delete and Earn
Array, Hash Table, Dynamic Programming
Medium
18
0.6%
1240Counter IIEasy
18
0.8%
1241Serialize and Deserialize N-ary Tree
String, Tree, Depth-First Search, Breadth-First Search
Hard
18
0.7%
1242Design HashMap
Array, Hash Table, Linked List, Design, Hash Function
Easy
18
0.7%
1243Monotonic Array
Array
Easy
18
0.6%
1244Find the Shortest Superstring
Array, String, Dynamic Programming, Bit Manipulation, Bitmask
Hard
18
0.5%
1245Unique Paths III
Array, Backtracking, Bit Manipulation, Matrix
Hard
18
0.8%
1246Find Common Characters
Array, Hash Table, String
Easy
18
0.7%
1247Subtract the Product and Sum of Digits of an Integer
Math
Easy
18
0.9%
1248Maximum Sum BST in Binary Tree
Dynamic Programming, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Hard
18
0.5%
1249Check If Array Pairs Are Divisible by k
Array, Hash Table, Counting
Medium
18
0.5%
1250Sort Array by Increasing Frequency
Array, Hash Table, Sorting
Easy
18
0.8%
1251Determine if Two Strings Are Close
Hash Table, String, Sorting, Counting
Medium
18
0.5%
1252Check if the Sentence Is Pangram
Hash Table, String
Easy
18
0.8%
1253Excel Sheet Column Number
Math, String
Easy
18
0.7%
1254Find Followers Count
Database
Easy
18
0.7%
1255Minimum Genetic Mutation
Hash Table, String, Breadth-First Search
Medium
18
0.6%
1256Investments in 2016
Database
Medium
18
0.5%
1257Minimum Number of Swaps to Make the String Balanced
Two Pointers, String, Stack, Greedy
Medium
18
0.8%
1258Meeting Scheduler
Array, Two Pointers, Sorting
Medium
18
0.6%
1259Count Hills and Valleys in an Array
Array
Easy
18
0.7%
1260Combination Sum III
Array, Backtracking
Medium
18
0.7%
1261Bitwise ORs of Subarrays
Array, Dynamic Programming, Bit Manipulation
Medium
18
0.6%
1262Maximum Absolute Sum of Any Subarray
Array, Dynamic Programming
Medium
18
0.7%
1263Divisible and Non-divisible Sums Difference
Math
Easy
18
0.9%
1264Minimum Operations to Make Binary Array Elements Equal to One I
Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum
Medium
18
0.8%
1265Special Binary String
String, Divide and Conquer, Sorting
Hard
18
0.8%
1266Minimum Number of Flips to Make Binary Grid Palindromic II
Array, Two Pointers, Matrix
Medium
18
0.3%
1267Maximum Value of an Ordered Triplet II
Array
Medium
18
0.6%
1268Longest Continuous Increasing Subsequence
Array
Easy
18
0.5%
1269Count Odd Numbers in an Interval Range
Math
Easy
18
0.5%
1270Find the Original Typed String II
String, Dynamic Programming, Prefix Sum
Hard
18
0.5%
1271Subdomain Visit Count
Array, Hash Table, String, Counting
Medium
18
0.8%
1272N-Repeated Element in Size 2N Array
Array, Hash Table
Easy
18
0.8%
1273Range Product Queries of Powers
Array, Bit Manipulation, Prefix Sum
Medium
18
0.6%
1274Number of People Aware of a Secret
Dynamic Programming, Queue, Simulation
Medium
18
0.6%
1275Maximize Alternating Sum Using Swaps
Array, Greedy, Union-Find, Sorting
Hard
18
0.6%
1276Split Array With Minimum Difference
Array, Prefix Sum
Medium
18
0.3%
1277Count Square Sum Triples
Math, Enumeration
Easy
18
0.8%
1278Maximum Product of Splitted Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
18
0.6%
1279Trionic Array I
Array
Easy
18
0.5%
1280Minimum Bitwise OR From Grid
Array, Greedy, Bit Manipulation, Matrix
Medium
18
0.3%
1281Department Top Three Salaries
Database
Hard
17
0.6%
1282Shuffle an Array
Array, Math, Design, Randomized
Medium
17
0.6%
1283Next Greater Element III
Math, Two Pointers, String
Medium
17
0.4%
1284Reverse Words in a String III
Two Pointers, String
Easy
17
0.8%
12852 Keys Keyboard
Math, Dynamic Programming
Medium
17
0.6%
1286Number of Submatrices That Sum to Target
Array, Hash Table, Matrix, Prefix Sum
Hard
17
0.7%
1287Minimum Number of Taps to Open to Water a Garden
Array, Dynamic Programming, Greedy
Hard
17
0.5%
1288Check if a Parentheses String Can Be Valid
String, Stack, Greedy
Medium
17
0.5%
1289Step-By-Step Directions From a Binary Tree Node to Another
String, Tree, Depth-First Search, Binary Tree
Medium
17
0.6%
1290Maximum Running Time of N Computers
Array, Binary Search, Greedy, Sorting
Hard
17
0.6%
1291Ugly Number II
Hash Table, Math, Dynamic Programming, Heap (Priority Queue)
Medium
17
0.5%
1292Largest 3-Same-Digit Number in String
String
Easy
17
0.7%
1293Number of Common Factors
Math, Enumeration, Number Theory
Easy
17
0.8%
1294Cherry Pickup
Array, Dynamic Programming, Matrix
Hard
17
0.4%
1295Design HashSet
Array, Hash Table, Linked List, Design, Hash Function
Easy
17
0.7%
1296Long Pressed Name
Two Pointers, String
Easy
17
0.3%
1297Minimum Number of K Consecutive Bit Flips
Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum
Hard
17
0.6%
1298Product Sales Analysis III
Database
Medium
17
0.5%
1299Relative Sort Array
Array, Hash Table, Sorting, Counting Sort
Easy
17
0.8%
1300Last Person to Fit in the Bus
Database
Medium
17
0.7%
1301Matrix Diagonal Sum
Array, Matrix
Easy
17
0.8%
1302Primary Department for Each Employee
Database
Easy
17
0.7%
1303Design Circular Deque
Array, Linked List, Design, Queue
Medium
17
0.6%
1304Replace Elements with Greatest Element on Right Side
Array
Easy
17
0.7%
1305Minimum Moves to Equal Array Elements
Array, Math
Medium
17
0.6%
1306Additive Number
String, Backtracking
Medium
17
0.3%
1307Customers Who Bought All Products
Database
Medium
17
0.6%
1308Split Linked List in Parts
Linked List
Medium
17
0.7%
1309Populating Next Right Pointers in Each Node II
Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
17
0.6%
1310XOR Queries of a Subarray
Array, Bit Manipulation, Prefix Sum
Medium
17
0.8%
1311Partition Labels
Hash Table, Two Pointers, String, Greedy
Medium
17
0.8%
1312Make Sum Divisible by P
Array, Hash Table, Prefix Sum
Medium
17
0.4%
1313Minimum Time to Visit a Cell In a Grid
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
17
0.6%
1314Remove Boxes
Array, Dynamic Programming, Memoization
Hard
17
0.5%
1315Longest Happy String
String, Greedy, Heap (Priority Queue)
Medium
17
0.7%
1316Find Minimum Time to Reach Last Room I
Array, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
17
0.6%
1317String Compression III
String
Medium
17
0.7%
1318Maximum Gap
Array, Sorting, Bucket Sort, Radix Sort
Medium
17
0.5%
1319Lowest Common Ancestor of a Binary Tree III
Hash Table, Two Pointers, Tree, Binary Tree
Medium
17
0.8%
1320Rotating the Box
Array, Two Pointers, Matrix
Medium
17
0.8%
1321Maximum Product of Three Numbers
Array, Math, Sorting
Easy
17
0.5%
1322String Matching in an Array
Array, String, String Matching
Easy
17
0.7%
1323Count the Number of Good Subarrays
Array, Hash Table, Sliding Window
Medium
17
0.7%
1324Shortest Subarray to be Removed to Make Array Sorted
Array, Two Pointers, Binary Search, Stack, Monotonic Stack
Medium
17
0.5%
1325Count Binary Substrings
Two Pointers, String
Easy
17
0.7%
1326Movie Rating
Database
Medium
17
0.4%
1327Nested List Weight Sum
Depth-First Search, Breadth-First Search
Medium
17
0.9%
1328Insert Delete GetRandom O(1) - Duplicates allowed
Array, Hash Table, Math, Design, Randomized
Hard
17
0.4%
1329Minimum Cost Walk in Weighted Graph
Array, Bit Manipulation, Union-Find, Graph Theory
Hard
17
0.7%
1330Ways to Express an Integer as Sum of Powers
Dynamic Programming
Medium
17
0.5%
1331Best Time to Buy and Sell Stock V
Array, Dynamic Programming
Medium
17
0.6%
1332Minimum Increments to Equalize Leaf Paths
Array, Dynamic Programming, Tree, Depth-First Search
Medium
17
0.4%
1333Game Play Analysis I
Database
Easy
17
0.8%
1334Maximize Subarrays After Removing One Conflicting Pair
Array, Segment Tree, Enumeration, Prefix Sum
Hard
17
0.6%
1335Best Time to Buy and Sell Stock with Transaction Fee
Array, Dynamic Programming, Greedy
Medium
17
0.7%
1336Smallest Subarrays With Maximum Bitwise OR
Array, Binary Search, Bit Manipulation, Sliding Window
Medium
17
0.6%
1337Rearranging Fruits
Array, Hash Table, Greedy, Sort
Hard
17
0.6%
1338Threshold Majority Queries
Array, Hash Table, Binary Search, Divide and Conquer, Counting, Prefix Sum
Hard
17
0.2%
1339Binary Number with Alternating Bits
Bit Manipulation
Easy
17
0.7%
1340Convert Integer to the Sum of Two No-Zero Integers
Math
Easy
17
0.6%
1341Minimum Sensors to Cover Grid
Math
Medium
17
0.7%
1342Twisted Mirror Path Count
Array, Dynamic Programming, Matrix
Medium
17
0.5%
1343Next Greater Numerically Balanced Number
Hash Table, Math, Backtracking, Counting, Enumeration
Medium
17
0.6%
1344Minimum Number of Operations to Make All Array Elements Equal to 1
Array, Math, Number Theory
Medium
17
0.5%
1345Largest Prime from Consecutive Prime Sum
Array, Math, Number Theory
Medium
17
0.4%
1346Power Update After K-th Largest Insertion I
Array, Hash Table, Math, Segment Tree, Sorting, Heap (Priority Queue)
Medium
17
0.7%
1347Earliest Finish Time for Land and Water Rides II
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
17
0.6%
1348Remove Invalid Parentheses
String, Backtracking, Breadth-First Search
Hard
15
0.5%
1349Sum of Left Leaves
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
15
0.6%
1350Battleships in a Board
Array, Depth-First Search, Matrix
Medium
15
0.8%
1351IPO
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
15
0.5%
1352Check Completeness of a Binary Tree
Tree, Breadth-First Search, Binary Tree
Medium
15
0.6%
1353Minimum Time Visiting All Points
Array, Math, Geometry
Easy
15
0.8%
1354Magnetic Force Between Two Balls
Array, Binary Search, Sorting
Medium
15
0.7%
1355Maximum Difference Between Increasing Elements
Array
Easy
15
0.7%
1356Extra Characters in a String
Array, Hash Table, String, Dynamic Programming, Trie
Medium
15
0.6%
1357Get the Size of a DataFrameEasy
15
0.8%
1358Convert a Number to Hexadecimal
Math, String, Bit Manipulation
Easy
15
0.5%
1359Arithmetic Slices
Array, Dynamic Programming, Sliding Window
Medium
15
0.6%
1360Strictly Palindromic Number
Math, Two Pointers, Brainteaser
Medium
15
0.9%
1361Number of Unique Subjects Taught by Each Teacher
Database
Easy
15
0.9%
1362Base 7
Math, String
Easy
15
0.5%
1363Maximum Length of Repeated Subarray
Array, Binary Search, Dynamic Programming, Sliding Window, Rolling Hash, Hash Function
Medium
15
0.5%
1364Implement Rand10() Using Rand7()
Math, Rejection Sampling, Randomized, Probability and Statistics
Medium
15
0.5%
1365Maximum Nesting Depth of the Parentheses
String, Stack
Easy
15
0.8%
1366Sorting the Sentence
String, Sorting
Easy
15
0.8%
1367Maximum Population Year
Array, Counting, Prefix Sum
Easy
15
0.6%
1368To Lower Case
String
Easy
15
0.8%
1369Customer Placing the Largest Number of Orders
Database
Easy
15
0.6%
1370Dota2 Senate
String, Greedy, Queue
Medium
15
0.5%
1371Remove Nodes From Linked List
Linked List, Stack, Recursion, Monotonic Stack
Medium
15
0.8%
1372The Number of the Smallest Unoccupied Chair
Array, Hash Table, Heap (Priority Queue)
Medium
15
0.6%
1373Find Kth Bit in Nth Binary String
String, Recursion, Simulation
Medium
15
0.7%
1374Count Number of Maximum Bitwise-OR Subsets
Array, Backtracking, Bit Manipulation, Enumeration
Medium
15
0.9%
1375Delete Characters to Make Fancy String
String
Easy
15
0.7%
1376Shortest Distance to a Character
Array, Two Pointers, String
Easy
15
0.7%
1377Minimum Value to Get Positive Step by Step Sum
Array, Prefix Sum
Easy
15
0.6%
1378Minimum Limit of Balls in a Bag
Array, Binary Search
Medium
15
0.7%
1379Smallest String With Swaps
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting
Medium
15
0.6%
1380Take Gifts From the Richest Pile
Array, Heap (Priority Queue), Simulation
Easy
15
0.8%
1381Maximum Average Pass Ratio
Array, Greedy, Heap (Priority Queue)
Medium
15
0.7%
1382Detect Cycles in 2D Grid
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
15
0.6%
1383Minimize the Maximum Edge Weight of Graph
Binary Search, Depth-First Search, Breadth-First Search, Graph Theory, Shortest Path
Medium
15
0.4%
1384First Completely Painted Row or Column
Array, Hash Table, Matrix
Medium
15
0.6%
1385Maximum Ascending Subarray Sum
Array
Easy
15
0.7%
1386Construct the Lexicographically Largest Valid Sequence
Array, Backtracking
Medium
15
0.7%
1387Apply Operations to an Array
Array, Two Pointers, Simulation
Easy
15
0.7%
1388Find the Minimum Cost Array Permutation
Array, Dynamic Programming, Bit Manipulation, Bitmask
Hard
15
0.3%
1389Count the Number of Square-Free Subsets
Array, Math, Dynamic Programming, Bit Manipulation, Number Theory, Bitmask
Medium
15
0.3%
1390Walking Robot Simulation II
Design, Simulation
Medium
15
0.4%
1391Lowest Common Ancestor of Deepest Leaves
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
15
0.8%
1392Count the Number of Powerful Integers
Math, String, Dynamic Programming
Hard
15
0.5%
1393Count Equal and Divisible Pairs in an Array
Array
Easy
15
0.8%
1394Count Largest Group
Hash Table, Math, Counting
Easy
15
0.7%
1395Smallest Number With All Set Bits
Math, Bit Manipulation
Easy
15
0.8%
1396Count Number of Balanced Permutations
Math, String, Dynamic Programming, Combinatorics
Hard
15
0.5%
1397Minimum Equal Sum of Two Arrays After Replacing Zeros
Array, Greedy
Medium
15
0.5%
1398Maximum Subarray Sum With Length Divisible by K
Array, Hash Table, Prefix Sum
Medium
15
0.5%
1399Largest Perimeter Triangle
Array, Math, Greedy, Sorting
Easy
15
0.6%
1400Find Words Containing Character
Array, String
Easy
15
0.9%
1401Distribute Candies Among Children II
Math, Combinatorics, Enumeration
Medium
15
0.6%
1402Find the Lexicographically Largest String From the Box I
Two Pointers, String, Enumeration
Medium
15
0.4%
1403Sum of k-Mirror Numbers
Math, Enumeration
Hard
15
0.6%
1404Trips and Users
Database
Hard
15
0.4%
1405Paint House III
Array, Dynamic Programming
Hard
15
0.6%
1406Find the Minimum Area to Cover All Ones I
Array, Matrix
Medium
15
0.8%
1407Binary Gap
Bit Manipulation
Easy
15
0.7%
1408Minimum Operations to Make Array Sum Divisible by K
Array, Math
Easy
15
0.9%
1409Minimize Maximum Pair Sum in Array
Array, Two Pointers, Greedy, Sorting
Medium
15
0.8%
1410Find All Possible Stable Binary Arrays I
Dynamic Programming, Prefix Sum
Medium
15
0.5%
1411Maximum Path Score in a Grid
Array, Dynamic Programming, Matrix
Medium
15
0.5%
1412Angle Between Hands of a Clock
Math
Medium
15
0.7%
1413Number of ZigZag Arrays I
Dynamic Programming, Prefix Sum
Hard
15
0.5%
1414Gray Code
Math, Backtracking, Bit Manipulation
Medium
13
0.7%
1415Binary Tree Level Order Traversal II
Tree, Breadth-First Search, Binary Tree
Medium
13
0.7%
14164Sum II
Array, Hash Table
Medium
13
0.6%
1417Find Largest Value in Each Tree Row
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
13
0.7%
1418Valid Square
Math, Geometry
Medium
13
0.5%
1419Minimum Number of Steps to Make Two Strings Anagram
Hash Table, String, Counting
Medium
13
0.8%
1420Design Browser History
Array, Linked List, Stack, Design, Doubly-Linked List, Data Stream
Medium
13
0.8%
1421Maximum Value at a Given Index in a Bounded Array
Math, Binary Search, Greedy
Medium
13
0.4%
1422Find Greatest Common Divisor of Array
Array, Math, Number Theory
Easy
13
0.8%
1423Longest Palindrome by Concatenating Two Letter Words
Array, Hash Table, String, Greedy, Counting
Medium
13
0.5%
1424Find Closest Number to Zero
Array
Easy
13
0.5%
1425Removing Stars From a String
String, Stack, Simulation
Medium
13
0.8%
1426Count Subarrays With Fixed Bounds
Array, Queue, Sliding Window, Monotonic Queue
Hard
13
0.7%
1427Minimum Common Value
Array, Hash Table, Two Pointers, Binary Search
Easy
13
0.6%
1428Add Two PromisesEasy
13
0.9%
1429Find the Minimum and Maximum Number of Nodes Between Critical Points
Linked List
Medium
13
0.7%
1430Compare Version Numbers
Two Pointers, String
Medium
13
0.5%
1431Contains Duplicate III
Array, Sliding Window, Sorting, Bucket Sort, Ordered Set
Hard
13
0.2%
1432Equal Row and Column Pairs
Array, Hash Table, Matrix, Simulation
Medium
13
0.7%
1433Open the Lock
Array, Hash Table, String, Breadth-First Search
Medium
13
0.6%
1434Painting the Walls
Array, Dynamic Programming
Hard
13
0.5%
1435Nth Magical Number
Math, Binary Search
Hard
13
0.4%
1436Sort Array By Parity II
Array, Two Pointers, Sorting
Easy
13
0.7%
1437Balance a Binary Search Tree
Divide and Conquer, Greedy, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
13
0.9%
1438Generate Binary Strings Without Adjacent Zeros
String, Backtracking, Bit Manipulation
Medium
13
0.9%
1439Delete Leaves With a Given Value
Tree, Depth-First Search, Binary Tree
Medium
13
0.8%
1440Number of Steps to Reduce a Number in Binary Representation to One
String, Bit Manipulation, Simulation
Medium
13
0.6%
1441Find the Winner of the Circular Game
Array, Math, Recursion, Queue, Simulation
Medium
13
0.8%
1442Sum of All Subset XOR Totals
Array, Math, Backtracking, Bit Manipulation, Combinatorics, Enumeration
Easy
13
0.9%
1443Nearest Exit from Entrance in Maze
Array, Breadth-First Search, Matrix
Medium
13
0.5%
1444Minimum Cost to Convert String I
Array, String, Graph Theory, Shortest Path
Medium
13
0.6%
1445Count Number of Teams
Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
Medium
13
0.7%
1446Remove All Adjacent Duplicates in String II
String, Stack
Medium
13
0.6%
1447Maximum Distance in Arrays
Array, Greedy
Medium
13
0.5%
1448Minimum Moves to Equal Array Elements II
Array, Math, Sorting
Medium
13
0.6%
1449Reach a Number
Math, Binary Search
Medium
13
0.5%
1450Fraction Addition and Subtraction
Math, String, Simulation
Medium
13
0.7%
1451Reverse Prefix of Word
Two Pointers, String, Stack
Easy
13
0.9%
1452Divide Nodes Into the Maximum Number of Groups
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
13
0.7%
1453Group Sold Products By The Date
Database
Easy
13
0.8%
1454Smallest Number in Infinite Set
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
13
0.7%
1455Sort Integers by The Number of 1 Bits
Array, Bit Manipulation, Sorting, Counting
Easy
13
0.8%
1456Cousins in Binary Tree II
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
13
0.8%
1457Determine Whether Matrix Can Be Obtained By Rotation
Array, Matrix
Easy
13
0.7%
1458Take K of Each Character From Left and Right
Hash Table, String, Sliding Window
Medium
13
0.5%
1459Next Greater Node In Linked List
Array, Linked List, Stack, Monotonic Stack
Medium
13
0.6%
1460Prime Palindrome
Math, Number Theory
Medium
13
0.3%
1461Identify the Largest Outlier in an Array
Array, Hash Table, Counting, Enumeration
Medium
13
0.4%
1462Adding Spaces to a String
Array, Two Pointers, String, Simulation
Medium
13
0.7%
1463Sort ByEasy
13
0.8%
1464Construct String With Repeat Limit
Hash Table, String, Greedy, Heap (Priority Queue), Counting
Medium
13
0.7%
1465Classes With at Least 5 Students
Database
Easy
13
0.6%
1466Reverse Odd Levels of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
13
0.9%
1467Day of the Year
Math, String
Easy
13
0.5%
1468Construct K Palindrome Strings
Hash Table, String, Greedy, Counting
Medium
13
0.7%
1469Minimize XOR
Greedy, Bit Manipulation
Medium
13
0.6%
1470Bitwise XOR of All Pairings
Array, Bit Manipulation, Brainteaser
Medium
13
0.7%
1471Grid Game
Array, Matrix, Prefix Sum
Medium
13
0.6%
1472Find the Number of Distinct Colors Among the Balls
Array, Hash Table, Simulation
Medium
13
0.5%
1473Degree of an Array
Array, Hash Table
Easy
13
0.6%
1474Max Sum of a Pair With Equal Sum of Digits
Array, Hash Table, Sorting, Heap (Priority Queue)
Medium
13
0.7%
1475Jump Game V
Array, Dynamic Programming, Sorting
Hard
13
0.8%
1476Number of Sub-arrays With Odd Sum
Array, Math, Dynamic Programming, Prefix Sum
Medium
13
0.6%
1477Hamming Distance
Bit Manipulation
Easy
13
0.8%
1478Two Furthest Houses With Different Colors
Array, Greedy
Easy
13
0.7%
1479Design Excel Sum Formula
Array, Hash Table, String, Graph Theory, Design, Topological Sort, Matrix
Hard
13
0.4%
1480Minimum Recolors to Get K Consecutive Black Blocks
String, Sliding Window
Easy
13
0.7%
1481Simple Bank System
Array, Hash Table, Design, Simulation
Medium
13
0.7%
1482Merge In Between Linked Lists
Linked List
Medium
13
0.8%
1483Calculate Special Bonus
Database
Easy
13
0.6%
1484Maximum Units on a Truck
Array, Greedy, Sorting
Easy
13
0.7%
1485Find the Count of Good Integers
Hash Table, Math, Combinatorics, Enumeration
Hard
13
0.7%
1486Count Vowel Substrings of a String
Hash Table, String
Easy
13
0.7%
1487Count the Number of Ideal Arrays
Math, Dynamic Programming, Combinatorics, Number Theory
Hard
13
0.6%
1488Count Complete Subarrays in an Array
Array, Hash Table, Sliding Window
Medium
13
0.8%
1489Get the Maximum Score
Array, Two Pointers, Dynamic Programming, Greedy
Hard
13
0.4%
1490Count Operations to Obtain Zero
Math, Simulation
Easy
13
0.8%
1491Rotate Function
Array, Math, Dynamic Programming
Medium
13
0.5%
1492Maximum Students Taking Exam
Array, Dynamic Programming, Bit Manipulation, Matrix, Bitmask
Hard
13
0.5%
1493Longest Subsequence Repeated k Times
Hash Table, Two Pointers, String, Backtracking, Counting, Enumeration
Hard
13
0.7%
1494Find Subsequence of Length K With the Largest Sum
Array, Hash Table, Sorting, Heap (Priority Queue)
Easy
13
0.6%
1495Find the Original Typed String I
String
Easy
13
0.7%
1496Find Lucky Integer in an Array
Array, Hash Table, Counting
Easy
13
0.8%
1497Maximum Fruits Harvested After at Most K Steps
Array, Binary Search, Sliding Window, Prefix Sum
Hard
13
0.6%
1498Maximum 69 Number
Math, Greedy
Easy
13
0.8%
1499Minimum Operations to Make Array Elements Zero
Array, Math, Bit Manipulation
Hard
13
0.6%
1500Minimum Operations to Make the Integer Zero
Bit Manipulation, Brainteaser, Enumeration
Medium
13
0.6%
1501The Two Sneaky Numbers of Digitville
Array, Hash Table, Math
Easy
13
0.9%
1502Find Resultant Array After Removing Anagrams
Array, Hash Table, String, Sorting
Easy
13
0.7%
1503Reshape the Matrix
Array, Matrix, Simulation
Easy
13
0.7%
1504Check If All 1's Are at Least Length K Places Away
Array
Easy
13
0.6%
1505Keep Multiplying Found Values by Two
Array, Hash Table, Sorting, Simulation
Easy
13
0.8%
1506Set Intersection Size At Least Two
Array, Greedy, Sorting
Hard
13
0.6%
1507Count Covered Buildings
Array, Hash Table, Sorting
Medium
13
0.6%
1508Four Divisors
Array, Math
Medium
13
0.6%
1509Max Dot Product of Two Subsequences
Array, Dynamic Programming
Hard
13
0.7%
1510Design Parking System
Design, Simulation, Counting
Easy
13
0.9%
1511Trionic Array II
Array, Dynamic Programming
Hard
13
0.5%
1512Maximum Score From Grid Operations
Array, Dynamic Programming, Matrix, Prefix Sum
Hard
13
0.6%
1513Minimum Initial Energy to Finish Tasks
Array, Greedy, Sorting
Hard
13
0.8%
1514Block Placement Queries
Array, Binary Search, Binary Indexed Tree, Segment Tree, Ordered Set
Hard
13
0.4%
1515Teemo Attacking
Array, Simulation
Easy
11
0.6%
1516Brick Wall
Array, Hash Table
Medium
11
0.6%
1517Find the Closest Palindrome
Math, String
Hard
11
0.3%
1518Knight Probability in Chessboard
Dynamic Programming
Medium
11
0.6%
1519Most Common Word
Array, Hash Table, String, Counting
Easy
11
0.5%
1520Leaf-Similar Trees
Tree, Depth-First Search, Binary Tree
Easy
11
0.7%
1521Increasing Order Search Tree
Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
11
0.8%
1522Distinct Subsequences II
String, Dynamic Programming
Hard
11
0.4%
1523Validate Stack Sequences
Array, Stack, Simulation
Medium
11
0.7%
1524Minimum Score Triangulation of Polygon
Array, Dynamic Programming
Medium
11
0.7%
1525Minimum Cost Tree From Leaf Values
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Medium
11
0.7%
1526Three Consecutive Odds
Array
Easy
11
0.7%
1527Find Users With Valid E-Mails
Database
Easy
11
0.4%
1528Maximum Number of Visible Points
Array, Math, Geometry, Sliding Window, Sorting
Hard
11
0.4%
1529Minimum Difference Between Highest and Lowest of K Scores
Array, Sliding Window, Sorting
Easy
11
0.7%
1530Minimum Number of Operations to Make Array Continuous
Array, Hash Table, Binary Search, Sliding Window
Hard
11
0.5%
1531Maximize the Confusion of an Exam
String, Binary Search, Sliding Window, Prefix Sum
Medium
11
0.7%
1532Minimized Maximum of Products Distributed to Any Store
Array, Binary Search, Greedy
Medium
11
0.6%
1533Escape the Spreading Fire
Array, Binary Search, Breadth-First Search, Matrix
Hard
11
0.4%
1534Minimum Replacements to Sort the Array
Array, Math, Greedy
Hard
11
0.5%
1535Minimum Penalty for a Shop
String, Prefix Sum
Medium
11
0.7%
1536Pass the Pillow
Math, Simulation
Easy
11
0.6%
1537Count Symmetric Integers
Math, Enumeration
Easy
11
0.8%
1538Elimination Game
Math, Recursion
Medium
11
0.5%
1539Remove Letter To Equalize Frequency
Hash Table, String, Counting
Easy
11
0.2%
1540Design In-Memory File System
Hash Table, String, Design, Trie, Sorting
Hard
11
0.5%
1541Merge Two Binary Trees
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
11
0.8%
1542Print Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
11
0.7%
1543Function CompositionEasy
11
0.9%
1544Allow One Function CallEasy
11
0.9%
1545Sort Vowels in a String
String, Sorting
Medium
11
0.8%
1546Count Pairs Whose Sum is Less than Target
Array, Two Pointers, Binary Search, Sorting
Easy
11
0.9%
1547Possible Bipartition
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
11
0.5%
1548Design File System
Hash Table, String, Design, Trie
Medium
11
0.7%
1549Number of Dice Rolls With Target Sum
Dynamic Programming
Medium
11
0.6%
1550Count Good Nodes in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
11
0.7%
1551Jump Game VI
Array, Dynamic Programming, Queue, Heap (Priority Queue), Monotonic Queue
Medium
11
0.5%
1552Cousins in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
11
0.6%
1553Second Minimum Time to Reach Destination
Breadth-First Search, Graph Theory, Shortest Path
Hard
11
0.6%
1554Number of Senior Citizens
Array, String
Easy
11
0.8%
1555Stone Game II
Array, Math, Dynamic Programming, Prefix Sum, Game Theory
Medium
11
0.7%
1556Minimum Swaps to Make Strings Equal
Math, String, Greedy
Medium
11
0.7%
1557Count Elements With Maximum Frequency
Array, Hash Table, Counting
Easy
11
0.8%
1558Find the Student that Will Replace the Chalk
Array, Binary Search, Simulation, Prefix Sum
Medium
11
0.5%
1559Sort the People
Array, Hash Table, String, Sorting
Easy
11
0.8%
1560Reach End of Array With Max Score
Array, Greedy
Medium
11
0.3%
1561Count the Number of Consistent Strings
Array, Hash Table, String, Bit Manipulation, Counting
Easy
11
0.9%
1562Number of Distinct Islands
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Sorting, Matrix, Hash Function
Medium
11
0.6%
1563Longest Subarray With Maximum Bitwise AND
Array, Bit Manipulation, Brainteaser
Medium
11
0.7%
1564Find the Longest Substring Containing Vowels in Even Counts
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
11
0.8%
1565Uncommon Words from Two Sentences
Hash Table, String, Counting
Easy
11
0.8%
1566Taking Maximum Energy From the Mystic Dungeon
Array, Dynamic Programming, Prefix Sum
Medium
11
0.6%
1567Maximum Height by Stacking Cuboids
Array, Dynamic Programming, Sorting
Hard
11
0.6%
1568Maximum Sum of Subsequence With Non-adjacent Elements
Array, Divide and Conquer, Dynamic Programming, Segment Tree
Hard
11
0.2%
1569Minimum String Length After Removing Substrings
String, Stack, Simulation
Easy
11
0.8%
1570Minimum Number of Removals to Make Mountain Array
Array, Binary Search, Dynamic Programming, Greedy
Hard
11
0.5%
1571Total Characters in String After Transformations II
Hash Table, Math, String, Dynamic Programming, Counting
Hard
11
0.6%
1572Minimum Total Distance Traveled
Array, Dynamic Programming, Sorting
Hard
11
0.6%
1573Minimum Number of Changes to Make Binary String Beautiful
String
Medium
11
0.8%
1574Smallest Even Multiple
Math, Number Theory
Easy
11
0.9%
1575Minimum Array End
Bit Manipulation
Medium
11
0.6%
1576Nested List Weight Sum II
Stack, Depth-First Search, Breadth-First Search
Medium
11
0.7%
1577Flip Columns For Maximum Number of Equal Rows
Array, Hash Table, Matrix
Medium
11
0.8%
1578Count Unguarded Cells in the Grid
Array, Matrix, Simulation
Medium
11
0.7%
1579Reconstruct Original Digits from English
Hash Table, Math, String
Medium
11
0.5%
1580Word Frequency
Shell
Medium
11
0.3%
1581Minimum Insertion Steps to Make a String Palindrome
String, Dynamic Programming
Hard
11
0.7%
1582Find Center of Star Graph
Graph Theory
Easy
11
0.9%
1583Maximize Subarray Sum After Removing All Occurrences of One Element
Array, Hash Table, Divide and Conquer, Dynamic Programming, Segment Tree, Prefix Sum
Hard
11
0.2%
1584Super Pow
Math, Divide and Conquer
Medium
11
0.4%
1585Average of Levels in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
11
0.7%
1586Course Schedule IV
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
11
0.6%
1587Count of Interesting Subarrays
Array, Hash Table, Prefix Sum
Medium
11
0.6%
1588Maximum Frequency After Subarray Operation
Array, Hash Table, Dynamic Programming, Greedy, Enumeration, Prefix Sum
Medium
11
0.3%
1589Longest Strictly Increasing or Strictly Decreasing Subarray
Array
Easy
11
0.6%
1590Maximum Total Damage With Spell Casting
Array, Hash Table, Two Pointers, Binary Search, Dynamic Programming, Sorting, Counting
Medium
11
0.5%
1591Sum of Distances
Array, Hash Table, Prefix Sum
Medium
11
0.5%
1592Length of Longest Fibonacci Subsequence
Array, Hash Table, Dynamic Programming
Medium
11
0.6%
1593Minimum Score of a Path Between Two Cities
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
11
0.6%
1594Find the Occurrence of First Almost Equal Substring
String, String Matching
Hard
11
0.2%
1595Apply Operations to Maximize Score
Array, Math, Stack, Greedy, Sorting, Monotonic Stack, Number Theory
Hard
11
0.5%
1596Three Divisors
Math, Enumeration, Number Theory
Easy
11
0.6%
1597Put Marbles in Bags
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
11
0.7%
1598Tenth Line
Shell
Easy
11
0.4%
1599Minimum Operations to Make Array Values Equal to K
Array, Hash Table
Easy
11
0.7%
1600Count Good Triplets in an Array
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
11
0.7%
1601Reformat Department Table
Database
Easy
11
0.8%
1602Process Tasks Using Servers
Array, Heap (Priority Queue)
Medium
11
0.4%
1603Patients With a Condition
Database
Easy
11
0.4%
1604Custom Sort String
Hash Table, String, Sorting
Medium
11
0.7%
1605Available Captures for Rook
Array, Matrix, Simulation
Easy
11
0.7%
1606Count Subarrays Where Max Element Appears at Least K Times
Array, Sliding Window
Medium
11
0.6%
1607Construct the Rectangle
Math
Easy
11
0.6%
1608Find Most Frequent Vowel and Consonant
Hash Table, String, Counting
Easy
11
0.9%
1609Can I Win
Math, Dynamic Programming, Bit Manipulation, Memoization, Game Theory, Bitmask
Medium
11
0.3%
1610Lexicographically Minimum String After Removing Stars
Hash Table, String, Stack, Greedy, Heap (Priority Queue)
Medium
11
0.5%
1611Maximum Difference Between Even and Odd Frequency II
String, Sliding Window, Enumeration, Prefix Sum
Hard
11
0.5%
1612Find the Pivot Integer
Math, Prefix Sum
Easy
11
0.8%
1613Find the K-th Character in String Game II
Math, Bit Manipulation, Recursion
Hard
11
0.5%
1614Finding Pairs With a Certain Sum
Array, Hash Table, Design
Medium
11
0.6%
1615Valid Word
String
Easy
11
0.5%
1616Add to Array-Form of Integer
Array, Math
Easy
11
0.5%
1617Count Partitions With Max-Min Difference at Most K
Array, Dynamic Programming, Queue, Sliding Window, Prefix Sum, Monotonic Queue
Medium
11
0.6%
1618Maximum Unique Subarray Sum After Deletion
Array, Hash Table, Greedy
Easy
11
0.4%
1619Transpose File
Shell
Medium
11
0.3%
1620Largest Number After Digit Swaps by Parity
Sorting, Heap (Priority Queue)
Easy
11
0.7%
1621Fruits Into Baskets III
Array, Binary Search, Segment Tree, Ordered Set
Medium
11
0.4%
1622Invalid Transactions
Array, Hash Table, String, Sorting
Medium
11
0.3%
1623Sort Matrix by Diagonals
Array, Sorting, Matrix
Medium
11
0.8%
1624Alice and Bob Playing Flower Game
Math
Medium
11
0.6%
1625Minimum Number of People to Teach
Array, Hash Table, Greedy
Medium
11
0.7%
1626Replace Non-Coprime Numbers in Array
Array, Math, Stack, Number Theory
Hard
11
0.6%
1627Maximum Number of Words You Can Type
Hash Table, String
Easy
11
0.8%
1628Power Grid Maintenance
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Heap (Priority Queue), Ordered Set
Medium
11
0.6%
1629Maximize the Minimum Powered City
Array, Binary Search, Greedy, Queue, Sliding Window, Prefix Sum
Hard
11
0.6%
1630Minimum Operations to Convert All Elements to Zero
Array, Hash Table, Stack, Greedy, Monotonic Stack
Medium
11
0.5%
1631Count of Matches in Tournament
Math, Simulation
Easy
11
0.9%
16321-bit and 2-bit Characters
Array
Easy
11
0.5%
1633Greatest Sum Divisible by Three
Array, Dynamic Programming, Greedy, Sorting
Medium
11
0.6%
1634Process String with Special Operations II
String, Simulation
Hard
11
0.4%
1635Count Special Triplets
Array, Hash Table, Counting
Medium
11
0.5%
1636Number of Smooth Descent Periods of a Stock
Array, Math, Two Pointers, Dynamic Programming, Sliding Window
Medium
11
0.7%
1637Number of Ways to Paint N × 3 Grid
Dynamic Programming
Hard
11
0.8%
1638Find Missing Elements
Array, Hash Table, Sorting
Easy
11
0.8%
1639Tallest Billboard
Array, Dynamic Programming
Hard
11
0.5%
1640Minimum ASCII Delete Sum for Two Strings
String, Dynamic Programming
Medium
11
0.7%
1641Maximum Square Area by Removing Fences From a Field
Array, Hash Table, Enumeration
Medium
11
0.5%
1642Minimum Removals to Balance Array
Array, Binary Search, Sliding Window, Sorting
Medium
11
0.5%
1643Restaurant Growth
Database
Medium
11
0.6%
1644Longest Balanced Substring II
Hash Table, String, Prefix Sum
Medium
11
0.4%
1645Jump Game IX
Array, Dynamic Programming
Medium
11
0.5%
1646Minimum Jumps to Reach End via Prime Teleportation
Array, Hash Table, Math, Breadth-First Search, Number Theory
Medium
11
0.4%
1647Minimum Moves to Make Array Complementary
Array, Hash Table, Prefix Sum
Medium
11
0.6%
1648Check if Array is Good
Array, Hash Table, Sorting
Easy
11
0.6%
1649Count the Number of Special Characters II
Hash Table, String
Medium
11
0.6%
1650Earliest Finish Time for Land and Water Rides I
Array, Two Pointers, Binary Search, Greedy, Sorting
Easy
11
0.7%
1651Number of Ways to Assign Edge Weights II
Array, Math, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search
Hard
11
0.7%
1652Find Right Interval
Array, Binary Search, Sorting
Medium
8
0.6%
1653Minesweeper
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
8
0.7%
1654K Inverse Pairs Array
Dynamic Programming
Hard
8
0.5%
1655Number of Days Between Two Dates
Math, String
Easy
8
0.5%
1656Constrained Subsequence Sum
Array, Dynamic Programming, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
Hard
8
0.6%
1657Maximum Number of Vowels in a Substring of Given Length
String, Sliding Window
Medium
8
0.6%
1658Path Crossing
Hash Table, String
Easy
8
0.6%
1659Delete Duplicate Folders in System
Array, Hash Table, String, Depth-First Search, Trie, Sorting, Hash Function
Hard
8
0.8%
1660Count Number of Pairs With Absolute Difference K
Array, Hash Table, Counting
Easy
8
0.9%
1661Count Nodes Equal to Average of Subtree
Tree, Depth-First Search, Binary Tree
Medium
8
0.9%
1662Most Frequent Even Element
Array, Hash Table, Counting
Easy
8
0.5%
1663Remove Digit From Number to Maximize Result
String, Greedy, Enumeration
Easy
8
0.5%
1664Design a Food Rating System
Array, Hash Table, String, Design, Heap (Priority Queue), Ordered Set
Medium
8
0.5%
1665Longest Cycle in a Graph
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
8
0.5%
1666Amount of Time for Binary Tree to Be Infected
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
8
0.7%
1667Arithmetic Slices II - Subsequence
Array, Dynamic Programming
Hard
8
0.6%
1668Count the Digits That Divide a Number
Math
Easy
8
0.9%
1669Strange Printer
String, Dynamic Programming
Hard
8
0.6%
1670Check if Object Instance of ClassMedium
8
0.3%
1671N-ary Tree Level Order Traversal
Tree, Breadth-First Search
Medium
8
0.7%
1672Number of Lines To Write String
Array, String
Easy
8
0.7%
1673Most Profit Assigning Work
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
8
0.6%
1674Rectangle Area II
Array, Segment Tree, Sweep Line, Ordered Set
Hard
8
0.6%
1675Verifying an Alien Dictionary
Array, Hash Table, String
Easy
8
0.6%
1676Binary Tree Cameras
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
8
0.5%
1677Satisfiability of Equality Equations
Array, String, Union-Find, Graph Theory
Medium
8
0.5%
1678Check If It Is a Good Array
Array, Math, Number Theory
Hard
8
0.7%
1679Widest Vertical Area Between Two Points Containing No Points
Array, Sorting
Easy
8
0.9%
1680Seat Reservation Manager
Design, Heap (Priority Queue)
Medium
8
0.7%
1681Longest Nice Substring
Hash Table, String, Divide and Conquer, Bit Manipulation, Sliding Window
Easy
8
0.6%
1682Check if the Rectangle Corner Is Reachable
Array, Math, Depth-First Search, Breadth-First Search, Union-Find, Geometry
Hard
8
0.3%
1683Build Array Where You Can Find The Maximum Exactly K Comparisons
Dynamic Programming, Prefix Sum
Hard
8
0.7%
1684Maximum Odd Binary Number
Math, String, Greedy
Easy
8
0.8%
1685Minimum Bit Flips to Convert Number
Bit Manipulation
Easy
8
0.9%
1686Basic Calculator IV
Hash Table, Math, String, Stack, Recursion
Hard
8
0.5%
1687Number Complement
Bit Manipulation
Easy
8
0.7%
1688Count Sub Islands
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
8
0.7%
1689Modify Graph Edge Weights
Graph Theory, Heap (Priority Queue), Shortest Path
Hard
8
0.6%
1690Find Minimum Operations to Make All Elements Divisible by Three
Array, Math
Easy
8
0.9%
1691Count the Number of Special Characters I
Hash Table, String
Easy
8
0.8%
1692Find Winner on a Tic Tac Toe Game
Array, Hash Table, Matrix, Simulation
Easy
8
0.5%
1693Pairs of Songs With Total Durations Divisible by 60
Array, Hash Table, Counting
Medium
8
0.5%
1694Find a Safe Walk Through a Grid
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
8
0.3%
1695Score of Parentheses
String, Stack
Medium
8
0.6%
1696Divide Intervals Into Minimum Number of Groups
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
8
0.6%
1697Tweet Counts Per Frequency
Hash Table, String, Binary Search, Design, Sorting, Ordered Set
Medium
8
0.5%
1698Separate Black and White Balls
Two Pointers, String, Greedy
Medium
8
0.6%
1699Sort Items by Groups Respecting Dependencies
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
8
0.7%
1700Two City Scheduling
Array, Greedy, Sorting
Medium
8
0.7%
1701Best Meeting Point
Array, Math, Sorting, Matrix
Hard
8
0.6%
1702Largest Combination With Bitwise AND Greater Than Zero
Array, Hash Table, Bit Manipulation, Counting
Medium
8
0.8%
1703Shortest Subarray With OR at Least K II
Array, Bit Manipulation, Sliding Window
Medium
8
0.5%
1704Most Beautiful Item for Each Query
Array, Binary Search, Sorting
Medium
8
0.6%
1705Find the Power of K-Size Subarrays I
Array, Sliding Window
Medium
8
0.6%
1706Shortest Distance After Road Addition Queries I
Array, Breadth-First Search, Graph Theory
Medium
8
0.6%
1707Find Score of an Array After Marking All Elements
Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
Medium
8
0.6%
1708Find Minimum Diameter After Merging Two Trees
Tree, Depth-First Search, Breadth-First Search, Graph Theory
Hard
8
0.6%
1709Number of Segments in a String
String
Easy
8
0.4%
1710Convert the Temperature
Math
Easy
8
0.9%
1711Maximum Coins From K Consecutive Bags
Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
Medium
8
0.3%
1712Coloring A Border
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
8
0.5%
1713Row With Maximum Ones
Array, Matrix
Easy
8
0.7%
1714Analyze User Website Visit Pattern
Array, Hash Table, String, Sorting
Medium
8
0.4%
1715Max Pair Sum in an Array
Array, Hash Table
Easy
8
0.6%
1716Count Univalue Subtrees
Tree, Depth-First Search, Binary Tree
Medium
8
0.6%
1717Find Good Days to Rob the Bank
Array, Dynamic Programming, Prefix Sum
Medium
8
0.5%
1718Maximum Product of Two Elements in an Array
Array, Sorting, Heap (Priority Queue)
Easy
8
0.8%
1719Check if One String Swap Can Make Strings Equal
Hash Table, String, Counting
Easy
8
0.5%
1720Minimum Operations to Make the Array Increasing
Array, Greedy
Easy
8
0.8%
1721Minimum Time to Complete Trips
Array, Binary Search
Medium
8
0.4%
1722Univalued Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
8
0.7%
1723Sum of Unique Elements
Array, Hash Table, Counting
Easy
8
0.8%
1724Minimum Number Game
Array, Sorting, Heap (Priority Queue), Simulation
Easy
8
0.9%
1725Find Indices of Stable Mountains
Array
Easy
8
0.9%
1726Parse Lisp Expression
Hash Table, String, Stack, Recursion
Hard
8
0.5%
1727Divide Array Into Equal Pairs
Array, Hash Table, Bit Manipulation, Counting
Easy
8
0.8%
1728Maximum Repeating Substring
String, Dynamic Programming, String Matching
Easy
8
0.4%
1729Minimum Operations to Make a Uni-Value Grid
Array, Math, Sorting, Matrix
Medium
8
0.7%
1730Minimum Index of a Valid Split
Array, Hash Table, Sorting
Medium
8
0.8%
1731Maximum Number of Points From Grid Queries
Array, Two Pointers, Breadth-First Search, Union-Find, Sorting, Heap (Priority Queue), Matrix
Hard
8
0.6%
1732Minimum Cuts to Divide a Circle
Math, Geometry
Easy
8
0.6%
1733Maximum Value of an Ordered Triplet I
Array
Easy
8
0.6%
1734Find the String with LCP
Array, String, Dynamic Programming, Greedy, Union-Find, Matrix
Hard
8
0.6%
1735Filter Elements from ArrayEasy
8
0.9%
1736Mirror Reflection
Math, Geometry, Number Theory
Medium
8
0.6%
1737Serialize and Deserialize BST
String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Search Tree, Binary Tree
Medium
8
0.6%
1738Check if Matrix Is X-Matrix
Array, Matrix
Easy
8
0.7%
1739Make Array Non-decreasing
Array, Stack, Greedy, Monotonic Stack
Medium
8
0.6%
1740Count the Hidden Sequences
Array, Prefix Sum
Medium
8
0.6%
1741All Paths From Source to Target
Backtracking, Depth-First Search, Breadth-First Search, Graph Theory
Medium
8
0.8%
1742Minimum Swaps to Sort by Digit Sum
Array, Hash Table, Sorting
Medium
8
0.5%
1743Maximum Product of Two Digits
Math, Sorting
Easy
8
0.7%
1744The Latest Login in 2020
Database
Easy
8
0.8%
1745Maximize the Number of Target Nodes After Connecting Trees I
Tree, Depth-First Search, Breadth-First Search
Medium
8
0.7%
1746String Without AAA or BBB
String, Greedy
Medium
8
0.5%
1747Maximize the Number of Target Nodes After Connecting Trees II
Tree, Depth-First Search, Breadth-First Search
Hard
8
0.7%
1748Lexicographically Smallest Equivalent String
String, Union-Find
Medium
8
0.8%
1749Maximum Difference Between Adjacent Elements in a Circular Array
Array
Easy
8
0.8%
1750Max Difference You Can Get From Changing an Integer
Math, Greedy
Medium
8
0.5%
1751Find Weighted Median Node in Tree
Array, Binary Search, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search
Hard
8
0.3%
1752Number of Squareful Arrays
Array, Hash Table, Math, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Hard
8
0.5%
1753Validate IP Address
String
Medium
8
0.3%
1754Matchsticks to Square
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
8
0.4%
1755Maximum Nesting Depth of Two Valid Parentheses Strings
String, Stack
Medium
8
0.7%
1756Minimum Difference in Sums After Removal of Elements
Array, Dynamic Programming, Heap (Priority Queue)
Hard
8
0.7%
1757Reorder Routes to Make All Paths Lead to the City Zero
Depth-First Search, Breadth-First Search, Graph Theory
Medium
8
0.7%
1758Decode the Message
Hash Table, String
Easy
8
0.9%
1759Find Common Elements Between Two Arrays
Array, Hash Table
Easy
8
0.8%
1760Maximum Subarray With Equal Products
Array, Math, Sliding Window, Enumeration, Number Theory
Easy
8
0.5%
1761Vowel Spellchecker
Array, Hash Table, String
Medium
8
0.6%
1762Friend Requests II: Who Has the Most Friends
Database
Medium
8
0.6%
1763Subsequence Sum After Capping Elements
Array, Two Pointers, Dynamic Programming, Sorting
Medium
8
0.3%
1764Design Spreadsheet
Array, Hash Table, String, Design, Matrix
Medium
8
0.7%
1765Minimum Moves to Move a Box to Their Target Location
Array, Breadth-First Search, Heap (Priority Queue), Matrix
Hard
8
0.5%
1766Successful Pairs of Spells and Potions
Array, Two Pointers, Binary Search, Sorting
Medium
8
0.5%
1767Minimum Cost to Reach Destination in Time
Array, Dynamic Programming, Graph Theory
Hard
8
0.4%
1768Check If Digits Are Equal in String After Operations I
Math, String, Simulation, Combinatorics, Number Theory
Easy
8
0.8%
1769Make Array Elements Equal to Zero
Array, Simulation, Prefix Sum
Easy
8
0.7%
1770Find and Replace Pattern
Array, Hash Table, String
Medium
8
0.8%
1771Largest Magic Square
Array, Matrix, Prefix Sum
Medium
8
0.8%
1772Find X-Sum of All K-Long Subarrays II
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
8
0.4%
1773Actors and Directors Who Cooperated At Least Three Times
Database
Easy
8
0.7%
1774Concatenate Non-Zero Digits and Multiply by Sum II
Math, String, Prefix Sum
Medium
8
0.2%
1775Count Partitions with Even Sum Difference
Array, Math, Prefix Sum
Easy
8
0.9%
1776Trim a Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
8
0.7%
1777Total Waviness of Numbers in Range I
Math, Dynamic Programming, Enumeration
Medium
8
0.9%
1778Count the Number of Computer Unlocking Permutations
Array, Math, Brainteaser, Combinatorics
Medium
8
0.6%
1779Apple Redistribution into Boxes
Array, Greedy, Sorting
Easy
8
0.8%
1780Smallest Subtree with all the Deepest Nodes
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
8
0.8%
1781Find Words That Can Be Formed by Characters
Array, Hash Table, String, Counting
Easy
8
0.7%
1782Find Players With Zero or One Losses
Array, Hash Table, Sorting, Counting
Medium
8
0.7%
1783Find Nth Smallest Integer With K One Bits
Math, Bit Manipulation, Combinatorics
Hard
8
0.4%
1784Minimum Cost Path with Teleportations
Array, Dynamic Programming, Matrix
Hard
8
0.5%
1785Maximize Cyclic Partition Score
Array, Dynamic Programming
Hard
8
0.1%
1786Minimum Deletions to Make Array Divisible
Array, Math, Sorting, Heap (Priority Queue), Number Theory
Hard
8
0.6%
1787Prime Number of Set Bits in Binary Representation
Math, Bit Manipulation
Easy
8
0.8%
1788Sum of Root To Leaf Binary Numbers
Tree, Depth-First Search, Binary Tree
Easy
8
0.8%
1789Minimum Operations to Equalize Binary String
Math, String, Breadth-First Search, Union-Find, Ordered Set
Hard
8
0.5%
1790Market Analysis I
Database
Medium
8
0.6%
1791Concatenation of Consecutive Binary Numbers
Math, Bit Manipulation, Simulation
Medium
8
0.7%
1792Maximize Spanning Tree Stability with Upgrades
Binary Search, Greedy, Union-Find, Graph Theory, Minimum Spanning Tree
Hard
8
0.7%
1793Get Biggest Three Rhombus Sums in a Grid
Array, Math, Sorting, Heap (Priority Queue), Matrix, Prefix Sum
Medium
8
0.7%
1794Count Submatrices with Top-Left Element and Sum Less Than k
Array, Matrix, Prefix Sum
Medium
8
0.7%
1795Minimum Absolute Difference in Sliding Submatrix
Array, Sorting, Matrix
Medium
8
0.8%
1796Equal Sum Grid Partition I
Array, Matrix, Enumeration, Prefix Sum
Medium
8
0.5%
1797Equal Sum Grid Partition II
Array, Hash Table, Matrix, Enumeration, Prefix Sum
Hard
8
0.4%
1798Lexicographically Smallest Generated String
String, Greedy, String Matching
Hard
8
0.5%
1799Maximize the Distance Between Points on a Square
Array, Math, Binary Search, Geometry, Sorting
Hard
8
0.5%
1800Separate the Digits in an Array
Array, Simulation
Easy
8
0.9%
1801Total Waviness of Numbers in Range II
Math, Dynamic Programming
Hard
8
0.6%
1802Number of ZigZag Arrays II
Math, Dynamic Programming
Hard
8
0.7%
1803Read N Characters Given Read4
Array, Simulation, Interactive
Easy
6
0.4%
1804Find the Celebrity
Two Pointers, Graph Theory, Interactive
Medium
6
0.5%
1805Range Sum Query - Mutable
Array, Divide and Conquer, Design, Binary Indexed Tree, Segment Tree
Medium
6
0.4%
1806Data Stream as Disjoint Intervals
Hash Table, Binary Search, Union-Find, Design, Data Stream, Ordered Set
Hard
6
0.6%
1807Max Stack
Linked List, Stack, Design, Doubly-Linked List, Ordered Set
Hard
6
0.5%
1808Remove Comments
Array, String
Medium
6
0.4%
1809Consecutive Numbers Sum
Math, Enumeration
Hard
6
0.4%
1810Building H2O
Concurrency
Medium
6
0.6%
1811The K Weakest Rows in a Matrix
Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
Easy
6
0.7%
1812Linked List in Binary Tree
Linked List, Tree, Depth-First Search, Binary Tree
Medium
6
0.5%
1813HTML Entity Parser
Hash Table, String
Medium
6
0.5%
1814Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree
Union-Find, Graph Theory, Sorting, Minimum Spanning Tree, Strongly Connected Component
Hard
6
0.7%
1815Check If Two String Arrays are Equivalent
Array, String
Easy
6
0.9%
1816Count Number of Homogenous Substrings
Math, String
Medium
6
0.6%
1817Maximum Number of Accepted Invitations
Array, Depth-First Search, Graph Theory, Matrix
Medium
6
0.5%
1818Count Unreachable Pairs of Nodes in an Undirected Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
6
0.5%
1819Minimum Cost to Make Array Equal
Array, Binary Search, Greedy, Sorting, Prefix Sum
Hard
6
0.5%
1820Count Palindromic Subsequences
String, Dynamic Programming
Hard
6
0.4%
1821Minimum Additions to Make Valid String
String, Dynamic Programming, Stack, Greedy
Medium
6
0.5%
1822Strong Password Checker
String, Greedy, Heap (Priority Queue)
Hard
6
0.2%
1823Find Bottom Left Tree Value
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
6
0.7%
1824Append Characters to String to Make Subsequence
Two Pointers, String, Greedy
Medium
6
0.7%
1825Maximum Length of Pair Chain
Array, Dynamic Programming, Greedy, Sorting
Medium
6
0.6%
1826Robot Collisions
Array, Stack, Sorting, Simulation
Hard
6
0.6%
1827Max Increase to Keep City Skyline
Array, Greedy, Matrix
Medium
6
0.9%
1828Score After Flipping Matrix
Array, Greedy, Bit Manipulation, Matrix
Medium
6
0.8%
1829Minimum Increment to Make Array Unique
Array, Greedy, Sorting, Counting
Medium
6
0.6%
1830Height Checker
Array, Sorting, Counting Sort
Easy
6
0.8%
1831Find the Maximum Sum of Node Values
Array, Dynamic Programming, Greedy, Bit Manipulation, Tree, Sorting
Hard
6
0.7%
1832Maximum Score Words Formed by Letters
Array, Hash Table, String, Dynamic Programming, Backtracking, Bit Manipulation, Counting, Bitmask
Hard
6
0.8%
1833Verbal Arithmetic Puzzle
Array, Math, String, Backtracking
Hard
6
0.3%
1834Number of Operations to Make Network Connected
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
6
0.7%
1835Maximum Performance of a Team
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
6
0.5%
1836Subrectangle Queries
Array, Design, Matrix
Medium
6
0.9%
1837Egg Drop With 2 Eggs and N Floors
Math, Dynamic Programming
Medium
6
0.7%
1838Minimum Swaps to Group All 1's Together II
Array, Sliding Window
Medium
6
0.7%
1839N-ary Tree Postorder Traversal
Stack, Tree, Depth-First Search
Easy
6
0.8%
1840N-ary Tree Preorder Traversal
Stack, Tree, Depth-First Search
Easy
6
0.8%
1841Minimum Moves to Convert String
String, Greedy
Easy
6
0.6%
1842Sum of Digits of String After Convert
String, Simulation
Easy
6
0.7%
1843Spiral Matrix IV
Array, Linked List, Matrix, Simulation
Medium
6
0.8%
1844Restore the Array From Adjacent Pairs
Array, Hash Table, Depth-First Search
Medium
6
0.8%
1845Super Washing Machines
Array, Greedy
Hard
6
0.4%
1846Shortest String That Contains Three Strings
String, Greedy, Enumeration
Medium
6
0.3%
1847Maximum Subarray Sum with One Deletion
Array, Dynamic Programming
Medium
6
0.5%
1848Chalkboard XOR Game
Array, Math, Bit Manipulation, Brainteaser, Game Theory
Hard
6
0.7%
1849Make Array Non-decreasing or Non-increasing
Array, Dynamic Programming, Greedy, Heap (Priority Queue)
Hard
6
0.7%
1850K-th Largest Perfect Subtree Size in Binary Tree
Tree, Depth-First Search, Sorting, Binary Tree
Medium
6
0.6%
1851Create Target Array in the Given Order
Array, Simulation
Easy
6
0.9%
1852Maximum Number of Moves in a Grid
Array, Dynamic Programming, Matrix
Medium
6
0.6%
1853Dot Product of Two Sparse Vectors
Array, Hash Table, Two Pointers, Design
Medium
6
0.9%
1854Day of the Week
Math
Easy
6
0.6%
1855Sliding Puzzle
Array, Dynamic Programming, Backtracking, Breadth-First Search, Memoization, Matrix
Hard
6
0.7%
1856Find the Middle Index in Array
Array, Prefix Sum
Easy
6
0.7%
1857Check If a Word Occurs As a Prefix of Any Word in a Sentence
Two Pointers, String, String Matching
Easy
6
0.7%
1858Binary Search Tree to Greater Sum Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
6
0.9%
1859Maximum Possible Number by Binary Concatenation
Array, Bit Manipulation, Enumeration
Medium
6
0.7%
1860Find Building Where Alice and Bob Can Meet
Array, Binary Search, Stack, Binary Indexed Tree, Segment Tree, Heap (Priority Queue), Monotonic Stack
Hard
6
0.5%
1861Find Triangular Sum of an Array
Array, Math, Simulation, Combinatorics, Number Theory
Medium
6
0.8%
1862Minimum Number of Operations to Sort a Binary Tree by Level
Tree, Breadth-First Search, Binary Tree
Medium
6
0.7%
1863Find the Key of the Numbers
Math
Easy
6
0.8%
1864Count Ways To Build Good Strings
Dynamic Programming
Medium
6
0.6%
1865Ways to Split Array Into Three Subarrays
Array, Two Pointers, Binary Search, Prefix Sum
Medium
6
0.3%
1866Convert BST to Greater Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
6
0.7%
1867Manhattan Distances of All Arrangements of Pieces
Math, Combinatorics
Hard
6
0.4%
1868Count Items Matching a Rule
Array, String
Easy
6
0.9%
1869Merge Nodes in Between Zeros
Linked List, Simulation
Medium
6
0.9%
1870Swap For Longest Repeated Character Substring
Hash Table, String, Sliding Window
Medium
6
0.4%
1871Find the Distance Value Between Two Arrays
Array, Two Pointers, Binary Search, Sorting
Easy
6
0.7%
1872Uncrossed Lines
Array, Dynamic Programming
Medium
6
0.7%
1873Maximum Number of Fish in a Grid
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
6
0.7%
1874Maximum Distance Between a Pair of Values
Array, Two Pointers, Binary Search
Medium
6
0.6%
1875Minimum Operations to Exceed Threshold Value II
Array, Heap (Priority Queue), Simulation
Medium
6
0.5%
1876Biggest Single Number
Database
Easy
6
0.7%
1877Split Array into Fibonacci Sequence
String, Backtracking
Medium
6
0.4%
1878Construct Smallest Number From DI String
String, Backtracking, Stack, Greedy
Medium
6
0.9%
1879Select DataEasy
6
0.8%
1880Length of Longest V-Shaped Diagonal Segment
Array, Dynamic Programming, Memoization, Matrix
Hard
6
0.6%
1881Display the First Three RowsEasy
6
0.9%
1882Maximum Subarray Min-Product
Array, Stack, Monotonic Stack, Prefix Sum
Medium
6
0.4%
1883Number of Distinct Islands II
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Sorting, Matrix, Hash Function
Hard
6
0.6%
1884Count Total Number of Colored Cells
Math
Medium
6
0.7%
1885Reshape Data: ConcatenateEasy
6
0.9%
1886Total Appeal of A String
Hash Table, String, Dynamic Programming
Hard
6
0.6%
1887Longest Non-decreasing Subarray From Two Arrays
Array, Dynamic Programming
Medium
6
0.3%
1888Minimum Fuel Cost to Report to the Capital
Tree, Depth-First Search, Breadth-First Search, Graph Theory
Medium
6
0.7%
1889Hash Divided String
String, Simulation
Medium
6
0.8%
1890Generate Fibonacci SequenceEasy
6
0.8%
1891Count the Number of Complete Components
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
6
0.8%
1892A Number After a Double Reversal
Math
Easy
6
0.8%
1893Top Travellers
Database
Easy
6
0.6%
1894Find the Divisibility Array of a String
Array, Math, String
Medium
6
0.4%
1895Shifting Letters
Array, String, Prefix Sum
Medium
6
0.5%
1896Minimum Number of Operations to Make Elements in Array Distinct
Array, Hash Table
Easy
6
0.7%
1897Inorder Successor in BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
6
0.5%
1898Divide a String Into Groups of Size k
String, Simulation
Easy
6
0.8%
1899Longest Special Path II
Array, Hash Table, Tree, Depth-First Search, Prefix Sum
Hard
6
0.2%
1900Buildings With an Ocean View
Array, Stack, Monotonic Stack
Medium
6
0.8%
1901Missing Element in Sorted Array
Array, Binary Search
Medium
6
0.6%
1902Maximum Number of Tasks You Can Assign
Array, Two Pointers, Binary Search, Greedy, Queue, Sorting, Monotonic Queue
Hard
6
0.5%
1903Stone Game VII
Array, Math, Dynamic Programming, Game Theory
Medium
6
0.6%
1904Total Characters in String After Transformations I
Hash Table, Math, String, Dynamic Programming, Counting
Medium
6
0.5%
1905Number of Subarrays with Bounded Maximum
Array, Two Pointers
Medium
6
0.6%
1906Generate a String With Characters That Have Odd Counts
String
Easy
6
0.8%
1907Delete Greatest Value in Each Row
Array, Sorting, Heap (Priority Queue), Matrix, Simulation
Easy
6
0.8%
1908Design Underground System
Hash Table, String, Design
Medium
6
0.7%
1909Find Closest Node to Given Two Nodes
Depth-First Search, Graph Theory
Medium
6
0.5%
1910Maximum Candies You Can Get from Boxes
Array, Breadth-First Search, Graph Theory
Hard
6
0.7%
19113Sum With Multiplicity
Array, Hash Table, Two Pointers, Sorting, Counting
Medium
6
0.5%
1912Maximum Difference Between Even and Odd Frequency I
Hash Table, String, Counting
Easy
6
0.6%
1913Make the XOR of All Segments Equal to Zero
Array, Hash Table, Dynamic Programming, Bit Manipulation, Counting
Hard
6
0.4%
1914Maximum Difference by Remapping a Digit
Math, Greedy
Easy
6
0.8%
1915Count Special Quadruplets
Array, Hash Table, Enumeration
Easy
6
0.6%
1916Unique 3-Digit Even Numbers
Array, Hash Table, Recursion, Enumeration
Easy
6
0.7%
1917Card Flipping Game
Array, Hash Table
Medium
6
0.5%
1918Find Nearest Point That Has the Same X or Y Coordinate
Array
Easy
6
0.7%
1919Shortest Word Distance II
Array, Hash Table, Two Pointers, String, Design
Medium
6
0.6%
1920Partition Array Such That Maximum Difference Is K
Array, Greedy, Sorting
Medium
6
0.8%
1921Longest Subsequence With Limited Sum
Array, Binary Search, Greedy, Sorting, Prefix Sum
Easy
6
0.7%
1922Closest Subsequence Sum
Array, Two Pointers, Dynamic Programming, Bit Manipulation, Sorting, Bitmask
Hard
6
0.4%
1923Sum of Absolute Differences in a Sorted Array
Array, Math, Prefix Sum
Medium
6
0.7%
1924Sum of All Odd Length Subarrays
Array, Math, Prefix Sum
Easy
6
0.8%
1925Reducing Dishes
Array, Dynamic Programming, Greedy, Sorting
Hard
6
0.8%
1926Unique Substrings in Wraparound String
String, Dynamic Programming
Medium
6
0.4%
1927Count The Repetitions
Two Pointers, String, Dynamic Programming
Hard
6
0.3%
1928Split the Array
Array, Hash Table, Counting
Easy
6
0.6%
1929Maximum Matching of Players With Trainers
Array, Two Pointers, Greedy, Sorting
Medium
6
0.8%
1930Task Scheduler II
Array, Hash Table, Simulation
Medium
6
0.5%
1931Zigzag Grid Traversal With Skip
Array, Matrix, Simulation
Easy
6
0.7%
1932Vowels Game in a String
Math, String, Brainteaser, Game Theory
Medium
6
0.8%
1933Letter Case Permutation
String, Backtracking, Bit Manipulation
Medium
6
0.8%
1934Partition Array for Maximum XOR and AND
Array, Math, Greedy, Bit Manipulation, Enumeration
Hard
6
0.2%
1935Find the Maximum Number of Fruits Collected
Array, Dynamic Programming, Matrix
Hard
6
0.6%
1936Collect Coins in a Tree
Array, Tree, Graph Theory, Topological Sort
Hard
6
0.4%
1937Allocate Mailboxes
Array, Math, Dynamic Programming, Sorting
Hard
6
0.6%
1938Maximum Frequency Stack
Hash Table, Stack, Design, Ordered Set
Hard
6
0.7%
1939Find the Minimum Area to Cover All Ones II
Array, Matrix, Enumeration
Hard
6
0.6%
1940Maximum Area of Longest Diagonal Rectangle
Array
Easy
6
0.5%
1941Smallest Missing Integer Greater Than Sequential Prefix Sum
Array, Hash Table, Sorting
Easy
6
0.4%
1942Find Closest Person
Math
Easy
6
0.9%
1943Promise Time LimitMedium
6
0.8%
1944Count Bowl Subarrays
Array, Stack, Monotonic Stack
Medium
6
0.5%
1945Maximum Product of the Length of Two Palindromic Subsequences
String, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
6
0.6%
1946Find the Number of Winning Players
Array, Hash Table, Counting
Easy
6
0.6%
1947Highest Grade For Each Student
Database
Medium
6
0.7%
1948Implement Router
Array, Hash Table, Binary Search, Design, Queue, Ordered Set
Medium
6
0.4%
1949Path Existence Queries in a Graph II
Array, Two Pointers, Binary Search, Dynamic Programming, Greedy, Bit Manipulation, Graph Theory, Sorting
Hard
6
0.3%
1950XOR Operation in an Array
Math, Bit Manipulation
Easy
6
0.9%
1951Water Bottles II
Math, Simulation
Medium
6
0.8%
1952Find Beautiful Indices in the Given Array I
Two Pointers, String, Binary Search, Rolling Hash, String Matching, Hash Function
Medium
6
0.4%
1953Calculate Delayed Arrival Time
Math
Easy
6
0.8%
1954Minimum Difficulty of a Job Schedule
Array, Dynamic Programming
Hard
6
0.6%
1955Find Minimum Time to Finish All Jobs
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Hard
6
0.5%
1956Maximum Count of Positive Integer and Negative Integer
Array, Binary Search, Counting
Easy
6
0.7%
1957Candy Crush
Array, Two Pointers, Matrix, Simulation
Medium
6
0.8%
1958Number of Even and Odd Bits
Bit Manipulation
Easy
6
0.7%
1959Minimum One Bit Operations to Make Integers Zero
Math, Dynamic Programming, Bit Manipulation, Recursion, Memoization
Hard
6
0.8%
1960Find Students Who Improved
Database
Medium
6
0.5%
1961Count Distinct Integers After Removing Zeros
Math, Dynamic Programming
Medium
6
0.2%
1962Best Team With No Conflicts
Array, Dynamic Programming, Sorting
Medium
6
0.5%
1963Count Collisions on a Road
String, Stack, Simulation
Medium
6
0.6%
1964Coupon Code Validator
Array, Hash Table, String, Sorting
Easy
6
0.6%
1965Maximum Profit from Trading Stocks with Discounts
Array, Dynamic Programming, Tree, Depth-First Search
Hard
6
0.6%
1966Design A Leaderboard
Hash Table, Design, Sorting
Medium
6
0.7%
1967Two-Letter Card Game
Array, Hash Table, String, Counting, Enumeration
Medium
6
0.1%
1968Difference Between Element Sum and Digit Sum of an Array
Array, Math
Easy
6
0.9%
1969Broken Calculator
Math, Greedy
Medium
6
0.6%
1970Sales Analysis III
Database
Easy
6
0.5%
1971Longest Turbulent Subarray
Array, Dynamic Programming, Sliding Window
Medium
6
0.5%
1972Maximize Area of Square Hole in Grid
Array, Sorting
Medium
6
0.6%
1973Design Auction System
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
6
0.4%
1974Construct the Minimum Bitwise Array I
Array, Bit Manipulation
Easy
6
0.9%
1975Minimum Number of Pushes to Type Word I
Math, String, Greedy
Easy
6
0.7%
1976Cache With Time LimitMedium
6
0.8%
1977Divide an Array Into Subarrays With Minimum Cost II
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
6
0.5%
1978Smallest Range I
Array, Math
Easy
6
0.7%
1979Apply Operations to Maximize Frequency Score
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Hard
6
0.4%
1980Partitioning Into Minimum Number Of Deci-Binary Numbers
String, Greedy
Medium
6
0.9%
1981Minimum Processing Time
Array, Greedy, Sorting
Medium
6
0.7%
1982Reverse Nodes in Even Length Groups
Linked List
Medium
6
0.6%
1983Flip Square Submatrix Vertically
Array, Two Pointers, Matrix
Easy
6
0.8%
1984Construct Uniform Parity Array I
Array, Math
Easy
6
0.8%
1985Check if Strings Can be Made Equal With Operations I
String
Easy
6
0.6%
1986Check if Strings Can be Made Equal With Operations II
Hash Table, String, Sorting
Medium
6
0.7%
1987Maximum Amount of Money Robot Can Earn
Array, Dynamic Programming, Matrix
Medium
6
0.5%
1988Decode the Slanted Ciphertext
String, Simulation
Medium
6
0.7%
1989Walking Robot Simulation
Array, Hash Table, Simulation
Medium
6
0.6%
1990Minimum Operations to Transform Array into Alternating Prime
Array, Math, Two Pointers, Binary Search, Sorting, Number Theory
Medium
6
0.5%
1991Closest Equal Element Queries
Array, Hash Table, Binary Search
Medium
6
0.5%
1992Number of Ways to Reach a Position After Exactly k Steps
Math, Dynamic Programming, Combinatorics
Medium
6
0.4%
1993Minimum Absolute Distance Between Mirror Pairs
Array, Hash Table, Math
Medium
6
0.6%
1994Mirror Distance of an Integer
Math
Easy
6
0.9%
1995Furthest Point From Origin
String, Counting
Easy
6
0.8%
1996Apply Operations to Make All Array Elements Equal to Zero
Array, Prefix Sum
Medium
6
0.3%
1997Cyclically Rotating a Grid
Array, Matrix, Simulation
Medium
6
0.7%
1998Sum of Variable Length Subarrays
Array, Prefix Sum
Easy
6
0.9%
1999Minimum Element After Replacement With Digit Sum
Array, Math
Easy
6
0.9%
2000Maximum Total Subarray Value I
Array, Greedy
Medium
6
0.7%
2001Count Salary Categories
Database
Medium
6
0.6%
2002Paint House
Array, Dynamic Programming
Medium
5
0.6%
2003Tree Node
Database
Medium
5
0.8%
2004Find Duplicate File in System
Array, Hash Table, String
Medium
5
0.7%
2005Stickers to Spell Word
Array, Hash Table, String, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
Hard
5
0.5%
2006Binary Trees With Factors
Array, Hash Table, Dynamic Programming, Sorting
Medium
5
0.5%
2007Maximize Sum Of Array After K Negations
Array, Greedy, Sorting
Easy
5
0.5%
2008Longest Repeating Substring
String, Binary Search, Dynamic Programming, Rolling Hash, Suffix Array, Hash Function
Medium
5
0.6%
2009Sequential Digits
Enumeration
Medium
5
0.7%
2010Count All Valid Pickup and Delivery Options
Math, Dynamic Programming, Combinatorics
Hard
5
0.6%
2011Find All Good Strings
String, Dynamic Programming, String Matching
Hard
5
0.5%
2012Minimum Deletions to Make Character Frequencies Unique
Hash Table, String, Greedy, Sorting
Medium
5
0.6%
2013Count Nice Pairs in an Array
Array, Hash Table, Math, Counting
Medium
5
0.5%
2014Minimum Sideway Jumps
Array, Dynamic Programming, Greedy
Medium
5
0.5%
2015Check if There is a Valid Partition For The Array
Array, Dynamic Programming
Medium
5
0.5%
2016Most Profitable Path in a Tree
Array, Tree, Depth-First Search, Breadth-First Search, Graph Theory
Medium
5
0.7%
2017Minimum Time to Complete All Tasks
Array, Binary Search, Stack, Greedy, Sorting
Hard
5
0.4%
2018The Number of Beautiful Subsets
Array, Hash Table, Math, Dynamic Programming, Backtracking, Sorting, Combinatorics
Medium
5
0.5%
2019Convert an Array Into a 2D Array With Conditions
Array, Hash Table
Medium
5
0.9%
2020Array Reduce TransformationEasy
5
0.9%
2021Length of Longest Subarray With at Most K Frequency
Array, Hash Table, Sliding Window
Medium
5
0.6%
2022Right Triangles
Array, Hash Table, Math, Combinatorics, Counting
Medium
5
0.5%
2023Count Integers in Intervals
Design, Segment Tree, Ordered Set
Hard
5
0.4%
2024Number of Arithmetic Triplets
Array, Hash Table, Two Pointers, Enumeration
Easy
5
0.9%
2025Optimal Partition of String
Hash Table, String, Greedy
Medium
5
0.8%
2026Poor Pigs
Math, Dynamic Programming, Combinatorics
Hard
5
0.6%
2027Largest Positive Integer That Exists With Its Negative
Array, Hash Table, Two Pointers, Sorting
Easy
5
0.7%
2028Add One Row to Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
5
0.6%
2029Replace Words
Array, Hash Table, String, Trie
Medium
5
0.7%
2030Differences Between Two ObjectsMedium
5
0.7%
2031Double a Number Represented as a Linked List
Linked List, Math, Stack
Medium
5
0.6%
2032Find Maximum Non-decreasing Array Length
Array, Binary Search, Dynamic Programming, Stack, Queue, Monotonic Stack, Prefix Sum, Monotonic Queue
Hard
5
0.2%
2033Remove Zero Sum Consecutive Nodes from Linked List
Hash Table, Linked List
Medium
5
0.5%
2034Validate Binary Tree Nodes
Tree, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Binary Tree
Medium
5
0.4%
2035Reverse Substrings Between Each Pair of Parentheses
String, Stack
Medium
5
0.7%
2036Count the Number of Inversions
Array, Dynamic Programming
Hard
5
0.3%
2037Count Triplets That Can Form Two Arrays of Equal XOR
Array, Hash Table, Math, Bit Manipulation, Prefix Sum
Medium
5
0.8%
2038Least Number of Unique Integers after K Removals
Array, Hash Table, Greedy, Sorting, Counting
Medium
5
0.6%
2039Remove Max Number of Edges to Keep Graph Fully Traversable
Union-Find, Graph Theory
Hard
5
0.7%
2040Bank Account Summary II
Database
Easy
5
0.8%
2041Average Waiting Time
Array, Simulation
Medium
5
0.7%
2042Alternating Groups I
Array, Sliding Window
Easy
5
0.7%
2043Kth Distinct String in an Array
Array, Hash Table, String, Counting
Easy
5
0.8%
2044Prefix and Suffix Search
Array, Hash Table, String, Design, Trie
Hard
5
0.4%
2045Minimum Number of Days to Disconnect Island
Array, Depth-First Search, Breadth-First Search, Matrix, Strongly Connected Component
Hard
5
0.6%
2046Minimum Operations to Make Array Equal to Target
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Hard
5
0.4%
2047Find the Largest Palindrome Divisible by K
Math, String, Dynamic Programming, Greedy, Number Theory
Hard
5
0.2%
2048Maximum XOR Score Subarray Queries
Array, Dynamic Programming
Hard
5
0.4%
2049Find Missing Observations
Array, Math, Simulation
Medium
5
0.6%
2050Insert Greatest Common Divisors in Linked List
Linked List, Math, Number Theory
Medium
5
0.9%
2051K-th Nearest Obstacle Queries
Array, Heap (Priority Queue)
Medium
5
0.5%
2052Distinct Prime Factors of Product of Array
Array, Hash Table, Math, Number Theory
Medium
5
0.5%
2053Sorted GCD Pair Queries
Array, Hash Table, Math, Binary Search, Combinatorics, Counting, Number Theory, Prefix Sum
Hard
5
0.2%
2054Snake in Matrix
Array, String, Simulation
Easy
5
0.8%
2055Projection Area of 3D Shapes
Array, Math, Geometry, Matrix
Easy
5
0.8%
2056Maximal Score After Applying K Operations
Array, Greedy, Heap (Priority Queue)
Medium
5
0.6%
2057Maximum Number of Moves to Kill All Pawns
Array, Math, Bit Manipulation, Breadth-First Search, Game Theory, Bitmask
Hard
5
0.3%
2058String Compression II
String, Dynamic Programming
Hard
5
0.5%
2059Minimum Division Operations to Make Array Non Decreasing
Array, Math, Greedy, Number Theory
Medium
5
0.3%
2060Longest Square Streak in an Array
Array, Hash Table, Binary Search, Dynamic Programming, Sorting
Medium
5
0.5%
2061Count Substrings With K-Frequency Characters I
Hash Table, String, Sliding Window
Medium
5
0.6%
2062Find if Array Can Be Sorted
Array, Bit Manipulation, Sorting
Medium
5
0.7%
2063Minimum Array Changes to Make Differences Equal
Array, Hash Table, Prefix Sum
Medium
5
0.2%
2064Maximum Size Subarray Sum Equals k
Array, Hash Table, Prefix Sum
Medium
5
0.5%
2065Minimum Operations to Reduce an Integer to 0
Dynamic Programming, Greedy, Bit Manipulation
Medium
5
0.6%
2066Kth Largest Sum in a Binary Tree
Tree, Breadth-First Search, Sorting, Binary Tree
Medium
5
0.6%
2067Sparse Matrix Multiplication
Array, Hash Table, Matrix
Medium
5
0.7%
2068Change Data TypeEasy
5
0.9%
2069Maximum Star Sum of a Graph
Array, Greedy, Graph Theory, Sorting, Heap (Priority Queue)
Medium
5
0.4%
2070Determine if String Halves Are Alike
String, Counting
Easy
5
0.8%
2071Find Maximum Removals From Source String
Array, Hash Table, Two Pointers, String, Dynamic Programming
Medium
5
0.4%
2072Maximize Amount After Two Days of Conversions
Array, String, Depth-First Search, Breadth-First Search, Graph Theory
Medium
5
0.6%
2073Cells with Odd Values in a Matrix
Array, Math, Simulation
Easy
5
0.8%
2074Count Prefix and Suffix Pairs I
Array, String, Trie, Rolling Hash, String Matching, Hash Function
Easy
5
0.8%
2075Neighboring Bitwise XOR
Array, Bit Manipulation
Medium
5
0.8%
2076Make Lexicographically Smallest Array by Swapping Elements
Array, Union-Find, Sorting
Medium
5
0.6%
2077Longest Subsequence With Decreasing Adjacent Difference
Array, Dynamic Programming
Medium
5
0.2%
2078Minimum Operations to Make Character Frequencies Equal
Hash Table, String, Dynamic Programming, Counting, Enumeration
Hard
5
0.3%
2079Count Substrings That Satisfy K-Constraint I
String, Sliding Window
Easy
5
0.8%
2080Convert Date to Binary
Math, String
Easy
5
0.9%
2081Goal Parser Interpretation
String
Easy
5
0.9%
2082Split a String in Balanced Strings
String, Greedy, Counting
Easy
5
0.9%
2083Check Knight Tour Configuration
Array, Depth-First Search, Breadth-First Search, Matrix, Simulation
Medium
5
0.6%
2084Check if All Characters Have Equal Number of Occurrences
Hash Table, String, Counting
Easy
5
0.8%
2085Find the XOR of Numbers Which Appear Twice
Array, Hash Table, Bit Manipulation
Easy
5
0.8%
2086Closest Prime Numbers in Range
Math, Number Theory
Medium
5
0.5%
2087Minimum Amount of Time to Fill Cups
Array, Greedy, Sorting, Heap (Priority Queue)
Easy
5
0.6%
2088Find the Number of Copy Arrays
Array, Math
Medium
5
0.5%
2089Maximum Alternating Subsequence Sum
Array, Dynamic Programming
Medium
5
0.6%
2090Minimum Insertions to Balance a Parentheses String
String, Stack, Greedy
Medium
5
0.5%
2091Count Vowel Strings in Ranges
Array, String, Prefix Sum
Medium
5
0.7%
2092Smallest Substring With Identical Characters I
Array, Binary Search, Enumeration
Hard
5
0.2%
2093Split With Minimum Sum
Math, Greedy, Sorting
Easy
5
0.7%
2094Count Pairs That Form a Complete Day II
Array, Hash Table, Counting
Medium
5
0.4%
2095Movement of Robots
Array, Brainteaser, Sorting, Prefix Sum
Medium
5
0.3%
2096Contain Virus
Array, Depth-First Search, Breadth-First Search, Matrix, Simulation
Hard
5
0.6%
2097Numbers With Same Consecutive Differences
Backtracking, Breadth-First Search
Medium
5
0.6%
2098Zero Array Transformation IV
Array, Dynamic Programming
Medium
5
0.3%
2099Is Object EmptyEasy
5
0.8%
2100Encrypt and Decrypt Strings
Array, Hash Table, String, Design, Trie
Hard
5
0.4%
2101Final Array State After K Multiplication Operations I
Array, Math, Heap (Priority Queue), Simulation
Easy
5
0.9%
2102Closest Node to Path in Tree
Array, Tree, Depth-First Search, Breadth-First Search
Hard
5
0.6%
2103Minimize Malware Spread
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
5
0.4%
2104Minimum Cost to Make Arrays Identical
Array, Greedy, Sorting
Medium
5
0.4%
2105Count Subarrays of Length Three With a Condition
Array
Easy
5
0.6%
2106Prime In Diagonal
Array, Math, Matrix, Number Theory
Easy
5
0.4%
2107Length of the Longest Valid Substring
Array, Hash Table, String, Sliding Window
Hard
5
0.4%
2108Merge Operations for Minimum Travel Time
Array, Dynamic Programming, Prefix Sum
Hard
5
0.3%
2109Find Minimum Time to Reach Last Room II
Array, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
5
0.7%
2110Minimum Moves to Spread Stones Over Grid
Array, Dynamic Programming, Backtracking, Bit Manipulation, Matrix, Bitmask
Medium
5
0.5%
2111Web Crawler Multithreaded
Depth-First Search, Breadth-First Search, Concurrency
Medium
5
0.5%
2112Inorder Successor in BST II
Tree, Binary Search Tree, Binary Tree
Medium
5
0.6%
2113Find All Groups of Farmland
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
5
0.8%
2114Robot Bounded In Circle
Math, String, Simulation
Medium
5
0.6%
2115Equal Rational Numbers
Math, String
Hard
5
0.5%
2116Stone Game V
Array, Math, Dynamic Programming, Game Theory
Hard
5
0.4%
2117Shift Distance Between Two Strings
Array, String, Prefix Sum
Medium
5
0.5%
2118Maximum Length of a Concatenated String with Unique Characters
Array, String, Backtracking, Bit Manipulation
Medium
5
0.5%
2119Sum of Good Numbers
Array
Easy
5
0.7%
2120Longest Word in Dictionary
Array, Hash Table, String, Trie, Sorting
Medium
5
0.5%
2121The Maze III
Array, String, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
5
0.5%
2122Create Sorted Array through Instructions
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
5
0.4%
2123Count the Number of Arrays with K Matching Adjacent Elements
Math, Combinatorics
Hard
5
0.6%
2124Minimum Deletions to Make String K-Special
Hash Table, String, Greedy, Sorting, Counting
Medium
5
0.7%
2125Find Maximum Area of a Triangle
Array, Hash Table, Math, Greedy, Geometry, Enumeration
Medium
5
0.3%
2126Earliest Second to Mark Indices II
Array, Binary Search, Greedy, Heap (Priority Queue)
Hard
5
0.2%
2127Maximum Product After K Increments
Array, Greedy, Heap (Priority Queue)
Medium
5
0.4%
2128Non-decreasing Subsequences
Array, Hash Table, Backtracking, Bit Manipulation
Medium
5
0.6%
2129Distribute Candies
Array, Hash Table
Easy
5
0.7%
2130Longest Palindrome After Substring Concatenation I
Two Pointers, String, Dynamic Programming, Enumeration
Medium
5
0.4%
2131Find the Kth Largest Integer in the Array
Array, String, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
Medium
5
0.5%
2132Find the K-Sum of an Array
Array, Sorting, Heap (Priority Queue)
Hard
5
0.4%
2133Minimize Maximum Component Cost
Binary Search, Union-Find, Graph Theory, Sorting
Medium
5
0.4%
2134Restore The Array
String, Dynamic Programming
Hard
5
0.5%
2135Chunk ArrayEasy
5
0.8%
2136Count Different Palindromic Subsequences
String, Dynamic Programming
Hard
5
0.5%
2137Minimum Score After Removals on a Tree
Array, Bit Manipulation, Tree, Depth-First Search
Hard
5
0.8%
2138Partition Array Into Three Parts With Equal Sum
Array, Greedy
Easy
5
0.4%
2139Count Islands With Total Value Divisible by K
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
5
0.6%
2140Count Prime-Gap Balanced Subarrays
Array, Math, Queue, Sliding Window, Number Theory, Monotonic Queue
Medium
5
0.2%
2141Increasing Decreasing String
Hash Table, String, Counting
Easy
5
0.8%
2142Maximum Total from Optimal Activation Order
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue)
Medium
5
0.3%
2143Minimum Array Sum
Array, Dynamic Programming
Medium
5
0.3%
2144Check If Digits Are Equal in String After Operations II
Math, String, Combinatorics, Number Theory
Hard
5
0.1%
2145Solve the Equation
Math, String, Simulation
Medium
5
0.5%
2146Maximum Path Quality of a Graph
Array, Backtracking, Graph Theory
Hard
5
0.6%
2147Map Sum Pairs
Hash Table, String, Design, Trie
Medium
5
0.6%
2148Minimum Index Sum of Two Lists
Array, Hash Table, String
Easy
5
0.6%
2149Sum of Digits in Base K
Math
Easy
5
0.8%
2150Find Substring With Given Hash Value
String, Sliding Window, Rolling Hash, Hash Function
Hard
5
0.3%
2151Partition Array Into K-Distinct Groups
Array, Hash Table, Counting
Medium
5
0.5%
2152Find Mirror Score of a String
Hash Table, String, Stack, Simulation
Medium
5
0.4%
2153Reorder Data in Log Files
Array, String, Sorting
Medium
5
0.6%
2154Minimum Average of Smallest and Largest Elements
Array, Two Pointers, Sorting
Easy
5
0.9%
2155Count The Number of Winning Sequences
String, Dynamic Programming
Hard
5
0.3%
2156Shortest Path in a Hidden Grid
Array, Depth-First Search, Breadth-First Search, Matrix, Interactive
Medium
5
0.4%
2157Sum of Beautiful Subsequences
Array, Math, Binary Indexed Tree, Number Theory
Hard
5
0.3%
2158Print Zero Even Odd
Concurrency
Medium
5
0.7%
2159Fill Missing DataEasy
5
0.7%
2160Balanced K-Factor Decomposition
Math, Backtracking, Number Theory
Medium
5
0.4%
2161Minimize String Length
Hash Table, String
Easy
5
0.8%
2162Find The Original Array of Prefix Xor
Array, Bit Manipulation
Medium
5
0.9%
2163Count Elements With Strictly Smaller and Greater Elements
Array, Sorting, Counting
Easy
5
0.6%
2164Maximum Area Rectangle With Point Constraints II
Array, Math, Binary Indexed Tree, Segment Tree, Geometry, Sorting
Hard
5
0.2%
2165Group the People Given the Group Size They Belong To
Array, Hash Table, Greedy
Medium
5
0.9%
2166Longest Palindrome After Substring Concatenation II
Two Pointers, String, Dynamic Programming
Hard
5
0.2%
2167Maximum Xor Product
Math, Greedy, Bit Manipulation
Medium
5
0.3%
2168Binary Tree Upside Down
Tree, Depth-First Search, Binary Tree
Medium
5
0.7%
2169Split Array With Same Average
Array, Hash Table, Math, Dynamic Programming, Bit Manipulation, Bitmask
Hard
5
0.3%
2170Sum of Perfect Square Ancestors
Array, Hash Table, Math, Tree, Depth-First Search, Counting, Number Theory
Hard
5
0.4%
2171Lexicographically Smallest Permutation Greater Than Target
Hash Table, String, Greedy, Counting, Enumeration
Medium
5
0.3%
2172Number of Valid Move Combinations On Chessboard
Array, String, Backtracking, Simulation
Hard
5
0.5%
2173Find Minimum Cost to Remove Array Elements
Array, Dynamic Programming
Medium
5
0.2%
2174Minimum Time to Complete All Deliveries
Math, Binary Search
Medium
5
0.4%
2175Find the Longest Valid Obstacle Course at Each Position
Array, Binary Search, Binary Indexed Tree
Hard
5
0.6%
2176Maximum Containers on a Ship
Math
Easy
5
0.8%
2177Non-negative Integers without Consecutive Ones
Dynamic Programming
Hard
5
0.4%
2178Partition Array into Disjoint Intervals
Array
Medium
5
0.5%
2179Sort Even and Odd Indices Independently
Array, Sorting
Easy
5
0.6%
2180Make Array Empty
Array, Binary Search, Greedy, Binary Indexed Tree, Segment Tree, Sorting, Ordered Set
Hard
5
0.3%
2181Escape a Large Maze
Array, Hash Table, Depth-First Search, Breadth-First Search
Hard
5
0.4%
2182Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts
Array, Greedy, Sorting
Medium
5
0.4%
2183Find the Largest Almost Missing Integer
Array, Hash Table
Easy
5
0.4%
2184Count Number of Ways to Place Houses
Dynamic Programming
Medium
5
0.4%
2185Smallest Index With Digit Sum Equal to Index
Array, Math
Easy
5
0.8%
2186Binary Prefix Divisible By 5
Array, Bit Manipulation
Easy
5
0.5%
2187Strong Friendship
Database
Medium
5
0.5%
2188Find Servers That Handled Most Number of Requests
Array, Heap (Priority Queue), Simulation, Ordered Set
Hard
5
0.5%
2189Zuma Game
String, Dynamic Programming, Stack, Breadth-First Search, Memoization
Hard
5
0.3%
2190Sum of Squares of Special Elements
Array, Enumeration
Easy
5
0.8%
2191Maximum Value of a String in an Array
Array, String
Easy
5
0.7%
2192Append K Integers With Minimal Sum
Array, Math, Greedy, Sorting
Medium
5
0.3%
2193Maximize Happiness of Selected Children
Array, Greedy, Sorting
Medium
5
0.6%
2194Maximize Active Section with Trade I
String, Enumeration
Medium
5
0.3%
2195Flatten Deeply Nested ArrayMedium
5
0.7%
2196IP to CIDR
String, Bit Manipulation
Medium
5
0.5%
2197Find Valid Pair of Adjacent Digits in String
Hash Table, String, Counting
Easy
5
0.6%
2198Memoize IIHard
5
0.4%
2199Minimum Deletions for At Most K Distinct Characters
Hash Table, String, Greedy, Sorting, Counting
Easy
5
0.7%
2200Sort the Matrix Diagonally
Array, Sorting, Matrix
Medium
5
0.8%
2201Count Paths That Can Form a Palindrome in a Tree
Hash Table, Bit Manipulation, Tree, Depth-First Search
Hard
5
0.5%
2202Count Residue Prefixes
Hash Table, String
Easy
5
0.7%
2203Merge BSTs to Create Single BST
Array, Hash Table, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Hard
5
0.4%
2204Dinner Plate Stacks
Hash Table, Stack, Design, Heap (Priority Queue)
Hard
5
0.3%
2205Smallest Divisible Digit Product II
Math, String, Backtracking, Greedy, Number Theory
Hard
5
0.1%
2206As Far from Land as Possible
Array, Dynamic Programming, Breadth-First Search, Matrix
Medium
5
0.5%
2207K-Concatenation Maximum Sum
Array, Dynamic Programming
Medium
5
0.3%
2208Number of Orders in the Backlog
Array, Heap (Priority Queue), Simulation
Medium
5
0.5%
2209Minimum Pair Removal to Sort Array II
Array, Hash Table, Linked List, Heap (Priority Queue), Simulation, Doubly-Linked List, Ordered Set
Hard
5
0.4%
2210Largest Element in an Array after Merge Operations
Array, Greedy
Medium
5
0.5%
2211Count Sorted Vowel Strings
Math, Dynamic Programming, Combinatorics
Medium
5
0.8%
2212Minimum Cost to Convert String II
Array, String, Dynamic Programming, Graph Theory, Trie, Shortest Path
Hard
5
0.6%
2213Partition Array to Minimize XOR
Array, Dynamic Programming, Bit Manipulation, Prefix Sum
Medium
5
0.4%
2214Reverse Degree of a String
String, Simulation
Easy
5
0.9%
2215Minimum K to Reduce Array Within Limit
Array, Binary Search
Medium
5
0.4%
2216Transformed Array
Array, Simulation
Easy
5
0.7%
2217Longest Balanced Subarray I
Array, Hash Table, Divide and Conquer, Segment Tree, Prefix Sum
Medium
5
0.7%
2218Longest Balanced Substring I
Hash Table, String, Counting, Enumeration
Medium
5
0.7%
2219Find the K-Beauty of a Number
Math, String, Sliding Window
Easy
5
0.6%
2220Minimum Amount of Time to Collect Garbage
Array, String, Prefix Sum
Medium
5
0.9%
2221Second Largest Digit in a String
Hash Table, String
Easy
5
0.5%
2222DNA Pattern Recognition
Database
Medium
5
0.9%
2223Human Traffic of Stadium
Database
Hard
5
0.5%
2224Find COVID Recovery Patients
Database
Medium
5
0.4%
2225Number of Subarrays With LCM Equal to K
Array, Math, Number Theory
Medium
5
0.5%
2226Maximum Product of Three Elements After One Replacement
Array, Math, Greedy, Sorting
Medium
5
0.5%
2227Number of Black Blocks
Array, Hash Table, Enumeration
Medium
5
0.4%
2228K Radius Subarray Averages
Array, Sliding Window
Medium
5
0.5%
2229Find the Number of Subsequences With Equal GCD
Array, Math, Dynamic Programming, Number Theory
Hard
5
0.3%
2230Decrypt String from Alphabet to Integer Mapping
String
Easy
5
0.8%
2231Maximum Number of Groups Entering a Competition
Array, Math, Binary Search, Greedy
Medium
5
0.7%
2232Check if Binary String Has at Most One Segment of Ones
String
Easy
5
0.5%
2233Count Sequences to K
Array, Math, Dynamic Programming, Memoization, Number Theory
Hard
5
0.4%
2234GCD of Odd and Even Sums
Math, Number Theory
Easy
5
0.9%
2235Distribute Money to Maximum Children
Math, Greedy
Easy
5
0.2%
2236Minimum Number of Seconds to Make Mountain Height Zero
Array, Math, Binary Search, Greedy, Heap (Priority Queue)
Medium
5
0.6%
2237Count Unhappy Friends
Array, Simulation
Medium
5
0.6%
2238Minimum Flips to Make a OR b Equal to c
Bit Manipulation
Medium
5
0.7%
2239Convert to Base -2
Math
Medium
5
0.6%
2240Construct Product Matrix
Array, Matrix, Prefix Sum
Medium
5
0.5%
2241Matrix Similarity After Cyclic Shifts
Array, Math, Matrix, Simulation
Easy
5
0.7%
2242Count Beautiful Numbers
Dynamic Programming
Hard
5
0.2%
2243Rearrange Products Table
Database
Easy
5
0.9%
2244Daily Leads and Partners
Database
Easy
5
0.9%
2245Reachable Nodes With Restrictions
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
5
0.6%
2246Maximum Partition Factor
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
5
0.3%
2247Random Pick Index
Hash Table, Math, Reservoir Sampling, Randomized
Medium
5
0.7%
2248Numbers At Most N Given Digit Set
Array, Math, String, Binary Search, Dynamic Programming
Hard
5
0.5%
2249Timeout CancellationEasy
5
0.9%
2250Valid Arrangement of Pairs
Array, Depth-First Search, Graph Theory, Eulerian Circuit
Hard
5
0.7%
2251Minimum Distance Between Three Equal Elements I
Array, Hash Table
Easy
5
0.7%
2252Minimum XOR Path in a Grid
Array, Dynamic Programming, Bit Manipulation, Matrix
Medium
5
0.4%
2253Minimum Distance Between Three Equal Elements II
Array, Hash Table
Medium
5
0.7%
2254Final Array State After K Multiplication Operations II
Array, Heap (Priority Queue), Simulation
Hard
5
0.1%
2255Minimum Distance to the Target Element
Array
Easy
5
0.6%
2256Traffic Signal Color
Math, String, Simulation
Easy
5
0.8%
2257Minimum Edge Reversals So Every Node Is Reachable
Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory
Hard
5
0.6%
2258Count Substrings Divisible By Last Digit
String, Dynamic Programming
Hard
5
0.2%
2259Find the Smallest Balanced Index
Array, Prefix Sum
Medium
5
0.2%
2260Maximize Sum of Squares of Digits
Math, Greedy
Medium
5
0.6%
2261Fizz Buzz Multithreaded
Concurrency
Medium
5
0.7%
2262Longest Balanced Substring After One Swap
Hash Table, String, Prefix Sum
Medium
5
0.1%
2263Count Stepping Numbers in Range
String, Dynamic Programming
Hard
5
0.3%
2264Monotone Increasing Digits
Math, Greedy
Medium
5
0.5%
2265Check if There is a Valid Path in a Grid
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
5
0.6%
2266Find the Sum of the Power of All Subsequences
Array, Dynamic Programming
Hard
5
0.4%
2267One Edit Distance
Two Pointers, String
Medium
5
0.3%
2268First Unique Number
Array, Hash Table, Design, Queue, Data Stream
Medium
5
0.6%
2269Maximize Count of Distinct Primes After Split
Array, Hash Table, Math, Segment Tree, Number Theory, Ordered Set
Hard
5
0.2%
2270Maximum Binary Tree
Array, Divide and Conquer, Stack, Tree, Monotonic Stack, Binary Tree
Medium
5
0.9%
2271Sales Person
Database
Easy
5
0.7%
2272Count K-th Roots in a Range
Math, Binary Search
Medium
5
0.2%
2273Shortest Path with Alternating Colors
Breadth-First Search, Graph Theory
Medium
5
0.5%
2274Circular Array Loop
Array, Hash Table, Two Pointers
Medium
5
0.4%
2275Masking Personal Information
String
Medium
5
0.6%
2276Minimum Swaps To Make Sequences Increasing
Array, Dynamic Programming
Hard
5
0.4%
2277Digit Operations to Make Two Integers Equal
Math, Graph Theory, Heap (Priority Queue), Number Theory, Shortest Path
Medium
5
0.3%
2278Maximum of Absolute Value Expression
Array, Math
Medium
5
0.5%
2279Find Subarrays With Equal Sum
Array, Hash Table
Easy
5
0.7%
2280Longest Palindromic Path in Graph
String, Dynamic Programming, Bit Manipulation, Graph Theory, Bitmask
Hard
5
0.2%
2281Count Good Meals
Array, Hash Table
Medium
5
0.3%
2282Find the Peaks
Array, Enumeration
Easy
5
0.8%
2283Weighted Word Mapping
Array, String, Simulation
Easy
5
0.9%
2284Get Maximum in Generated Array
Array, Simulation
Easy
5
0.5%
2285Maximum Total Subarray Value II
Array, Greedy, Segment Tree, Heap (Priority Queue)
Hard
5
0.4%
2286Shortest Cycle in a Graph
Breadth-First Search, Graph Theory
Hard
5
0.4%
2287Plates Between Candles
Array, String, Binary Search, Prefix Sum
Medium
5
0.5%
2288Maximize Sum of Device RatingsMedium
5
0.4%
2289Number of Pairs of Interchangeable Rectangles
Array, Hash Table, Math, Counting, Number Theory
Medium
5
0.5%
2290Process String with Special Operations I
String, Simulation
Medium
5
0.7%
2291Minimize the Difference Between Target and Chosen Elements
Array, Dynamic Programming, Matrix
Medium
5
0.4%
2292Queens That Can Attack the King
Array, Matrix, Simulation
Medium
5
0.7%
2293Subarrays Distinct Element Sum of Squares I
Array, Hash Table, Segment Tree
Easy
5
0.8%
2294Reachable Nodes In Subdivided Graph
Graph Theory, Heap (Priority Queue), Shortest Path
Hard
5
0.5%
2295Maximum Building Height
Array, Math, Sorting
Hard
5
0.7%
2296Longest Substring Of All Vowels in Order
String, Sliding Window
Medium
5
0.5%
2297Maximum Ice Cream Bars
Array, Greedy, Sorting, Counting Sort
Medium
5
0.8%
2298Maximum Number of Balloons
Hash Table, String, Counting
Easy
5
0.6%
2299Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold
Array, Sliding Window
Medium
5
0.7%
2300Maximum Subarray Sum After at Most K SwapsHard
5
0.1%
2301Maximum Sum Obtained of Any Permutation
Array, Greedy, Sorting, Prefix Sum
Medium
5
0.4%
2302Maximum Number of Occurrences of a Substring
Hash Table, String, Sliding Window
Medium
5
0.5%
2303Buy Two Chocolates
Array, Greedy, Sorting
Easy
5
0.7%
2304Dice Roll Simulation
Array, Dynamic Programming
Hard
5
0.5%
2305Count Subarrays With Majority Element I
Array, Hash Table, Divide and Conquer, Segment Tree, Merge Sort, Counting, Prefix Sum
Medium
5
0.8%

How to read this list

The tabs at the top split the questions by how recently people said they were asked in interviews. "Last 30 Days" is the past month, "Last 3 Months" is the past quarter, and so on. "All Time" is every question on record for this company.

Frequency is a score from 0 to 100 for how often a question showed up in that time window. A higher number means it came up more often, so the list starts with the most common questions first. Acceptance is the share of submissions that pass on LeetCode. Click any question to open it on LeetCode.