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Amazon LeetCode Questions

1968 questions all-time · 527 easy · 1074 medium · 367 hard
# Problem Difficulty Frequency Acceptance
1Two Sum
Array, Hash Table
Easy
100
0.6%
2LRU Cache
Hash Table, Linked List, Design, Doubly-Linked List
Medium
89
0.5%
3Trapping Rain Water
Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
Hard
87
0.7%
4Number of Islands
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
86
0.6%
5Longest Substring Without Repeating Characters
Hash Table, String, Sliding Window
Medium
84
0.4%
6Best Time to Buy and Sell Stock
Array, Dynamic Programming
Easy
83
0.6%
7Group Anagrams
Array, Hash Table, String, Sorting
Medium
80
0.7%
8Add Two Numbers
Linked List, Math, Recursion
Medium
79
0.5%
9Reorganize String
Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
79
0.6%
103Sum
Array, Two Pointers, Sorting
Medium
79
0.4%
11Longest Palindromic Substring
Two Pointers, String, Dynamic Programming
Medium
79
0.4%
12Merge Intervals
Array, Sorting
Medium
77
0.5%
13Container With Most Water
Array, Two Pointers, Greedy
Medium
77
0.6%
14Median of Two Sorted Arrays
Array, Binary Search, Divide and Conquer
Hard
76
0.5%
15Koko Eating Bananas
Array, Binary Search
Medium
75
0.5%
16Valid Parentheses
String, Stack
Easy
75
0.4%
17Course Schedule
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
75
0.5%
18Merge k Sorted Lists
Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort
Hard
74
0.6%
19Longest Common Prefix
Array, String, Trie
Easy
74
0.5%
20Rotting Oranges
Array, Breadth-First Search, Matrix
Medium
74
0.6%
21Subarray Sum Equals K
Array, Hash Table, Prefix Sum
Medium
73
0.5%
22Merge Sorted Array
Array, Two Pointers, Sorting
Easy
73
0.6%
23Search in Rotated Sorted Array
Array, Binary Search
Medium
71
0.5%
24Top K Frequent Elements
Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect
Medium
71
0.7%
25Maximum Subarray
Array, Divide and Conquer, Dynamic Programming
Medium
71
0.5%
26Longest Consecutive Sequence
Array, Hash Table, Union-Find
Medium
71
0.5%
27Copy List with Random Pointer
Hash Table, Linked List
Medium
70
0.6%
28Lowest Common Ancestor of a Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
70
0.7%
29Generate Parentheses
String, Dynamic Programming, Backtracking
Medium
70
0.8%
30Palindrome Number
Math
Easy
70
0.6%
31Word Ladder
Hash Table, String, Breadth-First Search
Hard
69
0.5%
32Majority Element
Array, Hash Table, Divide and Conquer, Sorting, Counting
Easy
69
0.7%
33Product of Array Except Self
Array, Prefix Sum
Medium
68
0.7%
34Merge Two Sorted Lists
Linked List, Recursion
Easy
68
0.7%
35Jump Game
Array, Dynamic Programming, Greedy
Medium
67
0.4%
36Climbing Stairs
Math, Dynamic Programming, Memoization
Easy
67
0.5%
37House Robber
Array, Dynamic Programming
Medium
67
0.5%
38Letter Combinations of a Phone Number
Hash Table, String, Backtracking
Medium
66
0.7%
39Course Schedule II
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
66
0.6%
40Word Search
Array, String, Backtracking, Depth-First Search, Matrix
Medium
65
0.5%
41Spiral Matrix
Array, Matrix, Simulation
Medium
65
0.6%
42Sliding Window Maximum
Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
Hard
65
0.5%
43Valid Anagram
Hash Table, String, Sorting
Easy
65
0.7%
44Next Permutation
Array, Two Pointers
Medium
64
0.5%
45Rotate Image
Array, Math, Matrix
Medium
64
0.8%
46Analyze User Website Visit Pattern
Array, Hash Table, String, Sorting
Medium
64
0.4%
47Kth Largest Element in an Array
Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
Medium
63
0.7%
48Coin Change
Array, Dynamic Programming, Breadth-First Search
Medium
63
0.5%
49Task Scheduler
Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
63
0.6%
50Remove Duplicates from Sorted Array
Array, Two Pointers
Easy
63
0.6%
51Meeting Rooms II
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
62
0.5%
52Find Median from Data Stream
Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream
Hard
62
0.5%
53Roman to Integer
Hash Table, Math, String
Easy
62
0.7%
54Subsets
Array, Backtracking, Bit Manipulation
Medium
62
0.8%
55Merge Strings Alternately
Two Pointers, String
Easy
62
0.8%
56Unique Paths
Math, Dynamic Programming, Combinatorics
Medium
62
0.7%
57Insert Delete GetRandom O(1)
Array, Hash Table, Math, Design, Randomized
Medium
61
0.6%
58Find Peak Element
Array, Binary Search
Medium
61
0.5%
59Pascal's Triangle
Array, Dynamic Programming
Easy
61
0.8%
60Word Break
Array, Hash Table, String, Dynamic Programming, Trie, Memoization
Medium
61
0.5%
61Reverse Integer
Math
Medium
60
0.3%
62First Missing Positive
Array, Hash Table
Hard
60
0.4%
63Jump Game II
Array, Dynamic Programming, Greedy
Medium
60
0.4%
64Move Zeroes
Array, Two Pointers
Easy
60
0.6%
65Asteroid Collision
Array, Stack, Simulation
Medium
60
0.5%
66Sort Colors
Array, Two Pointers, Sorting
Medium
60
0.7%
67Largest Rectangle in Histogram
Array, Stack, Monotonic Stack
Hard
60
0.5%
68Create Hello World FunctionEasy
60
0.8%
69Rotate Array
Array, Math, Two Pointers
Medium
60
0.5%
70Find First and Last Position of Element in Sorted Array
Array, Binary Search
Medium
60
0.5%
71N-Queens
Array, Backtracking
Hard
60
0.8%
72Longest Repeating Character Replacement
Hash Table, String, Sliding Window
Medium
60
0.6%
73Recyclable and Low Fat Products
Database
Easy
60
0.9%
74Best Time to Buy and Sell Stock II
Array, Dynamic Programming, Greedy
Medium
59
0.7%
75Min Stack
Stack, Design
Medium
59
0.6%
76Fruit Into Baskets
Array, Hash Table, Sliding Window
Medium
59
0.5%
77Minimum Window Substring
Hash Table, String, Sliding Window
Hard
59
0.5%
78Valid Sudoku
Array, Hash Table, Matrix
Medium
59
0.6%
79Binary Tree Maximum Path Sum
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
59
0.4%
804Sum
Array, Two Pointers, Sorting
Medium
59
0.4%
81Identify the Largest Outlier in an Array
Array, Hash Table, Counting, Enumeration
Medium
59
0.4%
82Single Number
Array, Bit Manipulation
Easy
58
0.8%
83Max Consecutive Ones III
Array, Binary Search, Sliding Window, Prefix Sum
Medium
58
0.7%
84Palindrome Linked List
Linked List, Two Pointers, Stack, Recursion
Easy
58
0.6%
85Serialize and Deserialize Binary Tree
String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree
Hard
58
0.6%
86Reverse Nodes in k-Group
Linked List, Recursion
Hard
57
0.7%
87Sqrt(x)
Math, Binary Search
Easy
57
0.4%
88Capacity To Ship Packages Within D Days
Array, Binary Search
Medium
57
0.7%
89Search a 2D Matrix
Array, Binary Search, Matrix
Medium
57
0.5%
90Daily Temperatures
Array, Stack, Monotonic Stack
Medium
57
0.7%
91Binary Tree Right Side View
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
57
0.7%
92Reverse Linked List
Linked List, Recursion
Easy
57
0.8%
93Single Element in a Sorted Array
Array, Binary Search
Medium
57
0.6%
94Zigzag Conversion
String
Medium
57
0.5%
95Binary Tree Zigzag Level Order Traversal
Tree, Breadth-First Search, Binary Tree
Medium
57
0.6%
96LFU Cache
Hash Table, Linked List, Design, Doubly-Linked List
Hard
57
0.5%
97Regular Expression Matching
String, Dynamic Programming, Recursion
Hard
56
0.3%
98All Nodes Distance K in Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
56
0.7%
99Search Insert Position
Array, Binary Search
Easy
56
0.5%
100Set Matrix Zeroes
Array, Hash Table, Matrix
Medium
56
0.6%
101Remove Element
Array, Two Pointers
Easy
56
0.6%
102Contains Duplicate
Array, Hash Table, Sorting
Easy
56
0.6%
103Find the Duplicate Number
Array, Two Pointers, Binary Search, Bit Manipulation
Medium
56
0.6%
104Binary Tree Level Order Traversal
Tree, Breadth-First Search, Binary Tree
Medium
55
0.7%
105Next Greater Element II
Array, Stack, Monotonic Stack
Medium
55
0.7%
106Missing Number
Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting
Easy
55
0.7%
107First Unique Character in a String
Hash Table, String, Queue, Counting
Easy
55
0.7%
108Pow(x, n)
Math, Recursion
Medium
54
0.4%
109Candy
Array, Greedy
Hard
54
0.5%
110Word Search II
Array, String, Backtracking, Trie, Matrix
Hard
54
0.4%
111Combination Sum
Array, Backtracking
Medium
54
0.8%
112Permutations
Array, Backtracking
Medium
54
0.8%
113Gas Station
Array, Greedy
Medium
54
0.5%
114String Compression
Two Pointers, String
Medium
54
0.6%
115Find the Index of the First Occurrence in a String
Two Pointers, String, String Matching
Easy
54
0.5%
116Two Sum II - Input Array Is Sorted
Array, Two Pointers, Binary Search
Medium
54
0.7%
117Concatenated Words
Array, String, Dynamic Programming, Depth-First Search, Trie, Sorting
Hard
54
0.5%
118String to Integer (atoi)
String
Medium
53
0.2%
119Integer to Roman
Hash Table, Math, String
Medium
53
0.7%
120Reorder List
Linked List, Two Pointers, Stack, Recursion
Medium
53
0.7%
121Maximum Product Subarray
Array, Dynamic Programming
Medium
53
0.4%
122Flood Fill
Array, Depth-First Search, Breadth-First Search, Matrix
Easy
53
0.7%
123Validate Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
53
0.4%
124Longest Increasing Subsequence
Array, Binary Search, Dynamic Programming
Medium
53
0.6%
125Next Greater Element I
Array, Hash Table, Stack, Monotonic Stack
Easy
53
0.8%
126Basic Calculator
Math, String, Stack, Recursion
Hard
53
0.5%
127Integer to English Words
Math, String, Recursion
Hard
53
0.4%
128Remove Nth Node From End of List
Linked List, Two Pointers
Medium
52
0.5%
129Valid Palindrome
Two Pointers, String
Easy
52
0.5%
130Diameter of Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
52
0.7%
131Middle of the Linked List
Linked List, Two Pointers
Easy
52
0.8%
132Linked List Cycle
Hash Table, Linked List, Two Pointers
Easy
52
0.5%
133Odd Even Linked List
Linked List
Medium
52
0.6%
134Word Break II
Array, Hash Table, String, Dynamic Programming, Backtracking, Trie, Memoization
Hard
52
0.6%
135Reverse Words in a String
Two Pointers, String
Medium
52
0.6%
136Plus One
Array, Math
Easy
51
0.5%
137Edit Distance
String, Dynamic Programming
Medium
51
0.6%
138Partition Equal Subset Sum
Array, Dynamic Programming
Medium
51
0.5%
139Maximum Profit in Job Scheduling
Array, Binary Search, Dynamic Programming, Sorting
Hard
51
0.5%
1403Sum Closest
Array, Two Pointers, Sorting
Medium
51
0.5%
141Basic Calculator II
Math, String, Stack
Medium
51
0.5%
142Search a 2D Matrix II
Array, Binary Search, Divide and Conquer, Matrix
Medium
51
0.6%
143Intersection of Two Arrays
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
51
0.8%
144Split Array Largest Sum
Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
Hard
51
0.6%
145Number of Provinces
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
51
0.7%
146Sum of Subarray Minimums
Array, Dynamic Programming, Stack, Monotonic Stack
Medium
51
0.4%
147Palindrome Partitioning
String, Dynamic Programming, Backtracking
Medium
50
0.7%
148Happy Number
Hash Table, Math, Two Pointers
Easy
50
0.6%
149Evaluate Division
Array, String, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Shortest Path
Medium
50
0.6%
150Balanced Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
50
0.6%
151Largest Number
Array, String, Greedy, Sorting
Medium
50
0.4%
152Contains Duplicate II
Array, Hash Table, Sliding Window
Easy
50
0.5%
153Fibonacci Number
Math, Dynamic Programming, Recursion, Memoization
Easy
50
0.7%
154Plates Between Candles
Array, String, Binary Search, Prefix Sum
Medium
50
0.5%
155Longest Valid Parentheses
String, Dynamic Programming, Stack
Hard
50
0.4%
156Rotate List
Linked List, Two Pointers
Medium
50
0.4%
157Max Consecutive Ones
Array
Easy
50
0.7%
158K Closest Points to Origin
Array, Math, Divide and Conquer, Geometry, Sorting, Heap (Priority Queue), Quickselect
Medium
50
0.7%
159Sudoku Solver
Array, Hash Table, Backtracking, Matrix
Hard
49
0.7%
160Check if Array Is Sorted and Rotated
Array
Easy
49
0.6%
161Maximum Frequency After Subarray Operation
Array, Hash Table, Dynamic Programming, Greedy, Enumeration, Prefix Sum
Medium
49
0.3%
162Combine Two Tables
Database
Easy
49
0.8%
163Minimum Size Subarray Sum
Array, Binary Search, Sliding Window, Prefix Sum
Medium
49
0.5%
164Decode String
String, Stack, Recursion
Medium
49
0.6%
165Evaluate Reverse Polish Notation
Array, Math, Stack
Medium
48
0.6%
166Time Based Key-Value Store
Hash Table, String, Binary Search, Design
Medium
48
0.5%
167Isomorphic Strings
Hash Table, String
Easy
48
0.5%
168Peak Index in a Mountain Array
Array, Binary Search
Medium
48
0.7%
169Search Suggestions System
Array, String, Binary Search, Trie, Sorting, Heap (Priority Queue)
Medium
48
0.7%
170Add Binary
Math, String, Bit Manipulation, Simulation
Easy
48
0.6%
171Remove Duplicates from Sorted Array II
Array, Two Pointers
Medium
48
0.6%
172Symmetric Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
48
0.6%
173Make Array Zero by Subtracting Equal Amounts
Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Simulation
Easy
48
0.7%
174Maximum Depth of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
47
0.8%
175Intersection of Two Linked Lists
Hash Table, Linked List, Two Pointers
Easy
47
0.6%
176Second Highest Salary
Database
Medium
47
0.5%
177Count Primes
Array, Math, Enumeration, Number Theory
Medium
47
0.4%
178Rotate String
String, String Matching
Easy
47
0.7%
179Subarrays with K Different Integers
Array, Hash Table, Sliding Window, Counting
Hard
47
0.7%
180Same Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
47
0.7%
181Construct Binary Tree from Preorder and Inorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
47
0.7%
182Find Minimum in Rotated Sorted Array
Array, Binary Search
Medium
47
0.5%
183Find All Anagrams in a String
Hash Table, String, Sliding Window
Medium
47
0.5%
184Concatenation of Array
Array, Simulation
Easy
47
0.9%
185Word Ladder II
Hash Table, String, Backtracking, Breadth-First Search
Hard
46
0.3%
186Lowest Common Ancestor of a Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
46
0.7%
187Fizz Buzz
Math, String, Simulation
Easy
46
0.8%
188Maximum Width of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
46
0.5%
189Vertical Order Traversal of a Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
Hard
46
0.5%
190Permutation in String
Hash Table, Two Pointers, String, Sliding Window
Medium
46
0.5%
191Random Pick with Weight
Array, Math, Binary Search, Prefix Sum, Randomized
Medium
46
0.5%
192Article Views I
Database
Easy
46
0.8%
193The kth Factor of n
Math, Number Theory
Medium
46
0.7%
194Reverse Linked List II
Linked List
Medium
45
0.5%
195Surrounded Regions
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
45
0.5%
196Employees Earning More Than Their Managers
Database
Easy
45
0.7%
197Find K Closest Elements
Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue)
Medium
45
0.5%
198Lowest Common Ancestor of a Binary Tree III
Hash Table, Two Pointers, Tree, Binary Tree
Medium
45
0.8%
199Minimum Health to Beat Game
Array, Greedy
Medium
45
0.6%
200Minimum Path Sum
Array, Dynamic Programming, Matrix
Medium
45
0.7%
201Simplify Path
String, Stack
Medium
45
0.5%
202Populating Next Right Pointers in Each Node
Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
45
0.7%
203Reverse String
Two Pointers, String
Easy
45
0.8%
204Pacific Atlantic Water Flow
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
45
0.6%
205Rearrange Array Elements by Sign
Array, Two Pointers, Simulation
Medium
45
0.8%
206Minimum Time to Complete All Deliveries
Math, Binary Search
Medium
45
0.4%
207Subsets II
Array, Backtracking, Bit Manipulation
Medium
44
0.6%
208Linked List Cycle II
Hash Table, Linked List, Two Pointers
Medium
44
0.6%
209Sort List
Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort
Medium
44
0.6%
210Kth Smallest Element in a BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
44
0.8%
211Target Sum
Array, Dynamic Programming, Backtracking
Medium
44
0.5%
212Top K Frequent Words
Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting
Medium
44
0.6%
213Maximal Rectangle
Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
Hard
44
0.6%
214Reverse Pairs
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
44
0.3%
215Min Cost Climbing Stairs
Array, Dynamic Programming
Easy
44
0.7%
216Partition Labels
Hash Table, Two Pointers, String, Greedy
Medium
44
0.8%
217Online Stock Span
Stack, Design, Monotonic Stack, Data Stream
Medium
44
0.7%
218Divide Two Integers
Math, Bit Manipulation
Medium
43
0.2%
219Sort Characters By Frequency
Hash Table, String, Sorting, Heap (Priority Queue), Bucket Sort, Counting
Medium
43
0.8%
220Managers with at Least 5 Direct Reports
Database
Medium
43
0.5%
221Binary Search
Array, Binary Search
Easy
43
0.6%
222Cheapest Flights Within K Stops
Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
43
0.4%
223Squares of a Sorted Array
Array, Two Pointers, Sorting
Easy
43
0.7%
224Design Parking System
Design, Simulation, Counting
Easy
43
0.9%
225Average Time of Process per Machine
Database
Easy
43
0.7%
226Length of Last Word
String
Easy
43
0.6%
227Invert Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
43
0.8%
228House Robber III
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Medium
43
0.6%
229Remove Duplicates from Sorted List
Linked List
Easy
42
0.6%
230Majority Element II
Array, Hash Table, Sorting, Counting
Medium
42
0.6%
231Valid Palindrome II
Two Pointers, String, Greedy
Easy
42
0.4%
232Kth Largest Element in a Stream
Tree, Design, Binary Search Tree, Heap (Priority Queue), Binary Tree, Data Stream
Easy
42
0.6%
233Boats to Save People
Array, Two Pointers, Greedy, Sorting
Medium
42
0.6%
234Minimum Number of Days to Make m Bouquets
Array, Binary Search
Medium
42
0.6%
235Find Triangular Sum of an Array
Array, Math, Simulation, Combinatorics, Number Theory
Medium
42
0.8%
236Remove K Digits
String, Stack, Greedy, Monotonic Stack
Medium
42
0.4%
237Non-overlapping Intervals
Array, Dynamic Programming, Greedy, Sorting
Medium
42
0.6%
238Contiguous Array
Array, Hash Table, Prefix Sum
Medium
42
0.5%
239Set Mismatch
Array, Hash Table, Bit Manipulation, Sorting
Easy
42
0.4%
240Snakes and Ladders
Array, Breadth-First Search, Matrix
Medium
42
0.5%
241Critical Connections in a Network
Depth-First Search, Graph Theory, Biconnected Component
Hard
42
0.6%
242Frequency of the Most Frequent Element
Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
Medium
42
0.4%
243Swap Nodes in Pairs
Linked List, Recursion
Medium
41
0.7%
244Rising Temperature
Database
Easy
41
0.5%
245Is Subsequence
Two Pointers, String, Dynamic Programming
Easy
41
0.5%
246Trapping Rain Water II
Array, Breadth-First Search, Heap (Priority Queue), Matrix
Hard
41
0.6%
247Count and Say
String
Medium
40
0.6%
248Longest Palindromic Subsequence
String, Dynamic Programming
Medium
40
0.7%
249Big Countries
Database
Easy
40
0.7%
250Smallest Range Covering Elements from K Lists
Array, Hash Table, Greedy, Sliding Window, Sorting, Heap (Priority Queue)
Hard
40
0.7%
251Open the Lock
Array, Hash Table, String, Breadth-First Search
Medium
40
0.6%
252Sort an Array
Array, Divide and Conquer, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort
Medium
40
0.6%
253Maximum Width Ramp
Array, Two Pointers, Stack, Monotonic Stack
Medium
40
0.6%
254Maximum Number of Vowels in a Substring of Given Length
String, Sliding Window
Medium
40
0.6%
255Furthest Building You Can Reach
Array, Greedy, Heap (Priority Queue)
Medium
40
0.5%
256Add Two Integers
Math
Easy
40
0.9%
257Decode Ways
String, Dynamic Programming
Medium
40
0.4%
258Binary Tree Inorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
40
0.8%
259House Robber II
Array, Dynamic Programming
Medium
40
0.5%
260Design Twitter
Hash Table, Linked List, Design, Heap (Priority Queue)
Medium
40
0.4%
261Can Place Flowers
Array, Greedy
Easy
40
0.3%
262Exclusive Time of Functions
Array, Stack
Medium
40
0.7%
263Palindromic Substrings
Two Pointers, String, Dynamic Programming
Medium
40
0.7%
264Accounts Merge
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting
Medium
40
0.6%
265Design HashMap
Array, Hash Table, Linked List, Design, Hash Function
Easy
40
0.7%
266Making A Large Island
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Hard
40
0.6%
267Greatest Common Divisor of Strings
Math, String
Easy
40
0.5%
268Product Sales Analysis III
Database
Medium
40
0.5%
269Average Selling Price
Database
Easy
40
0.4%
270Kth Missing Positive Number
Array, Binary Search
Easy
40
0.6%
271Maximum Units on a Truck
Array, Greedy, Sorting
Easy
40
0.7%
272Combination Sum II
Array, Backtracking
Medium
39
0.6%
273Unique Paths II
Array, Dynamic Programming, Matrix
Medium
39
0.4%
274Triangle
Array, Dynamic Programming
Medium
39
0.6%
275Implement Trie (Prefix Tree)
Hash Table, String, Design, Trie
Medium
39
0.7%
276Power of Two
Math, Bit Manipulation, Recursion
Easy
39
0.5%
277Implement Queue using Stacks
Stack, Design, Queue
Easy
39
0.7%
278Reverse Vowels of a String
Two Pointers, String
Easy
39
0.6%
279Assign Cookies
Array, Two Pointers, Greedy, Sorting
Easy
39
0.6%
28001 Matrix
Array, Dynamic Programming, Breadth-First Search, Matrix
Medium
39
0.5%
281Find Customer Referee
Database
Easy
39
0.7%
282Monthly Transactions I
Database
Medium
39
0.6%
283Count Good Numbers
Math, Recursion
Medium
39
0.6%
284Maximum Sum of Distinct Subarrays With Length K
Array, Hash Table, Sliding Window
Medium
39
0.4%
285Search in Rotated Sorted Array II
Array, Binary Search
Medium
38
0.4%
286Delete Node in a Linked List
Linked List
Medium
38
0.8%
287Design Tic-Tac-Toe
Array, Hash Table, Design, Matrix, Simulation
Medium
38
0.6%
288Russian Doll Envelopes
Array, Binary Search, Dynamic Programming, Sorting
Hard
38
0.4%
289Delete Node in a BST
Tree, Binary Search Tree, Binary Tree
Medium
38
0.5%
290Maximum Average Subarray I
Array, Sliding Window
Easy
38
0.5%
291Max Area of Island
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
38
0.7%
292Kids With the Greatest Number of Candies
Array
Easy
38
0.9%
293Maximum Points You Can Obtain from Cards
Array, Sliding Window, Prefix Sum
Medium
38
0.6%
294Running Sum of 1d Array
Array, Prefix Sum
Easy
38
0.9%
295Sum of Subarray Ranges
Array, Stack, Monotonic Stack
Medium
38
0.6%
296Sum of Total Strength of Wizards
Array, Stack, Monotonic Stack, Prefix Sum
Hard
38
0.3%
297Recover Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
38
0.6%
298Convert Sorted Array to Binary Search Tree
Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
Easy
38
0.8%
299Clone Graph
Hash Table, Depth-First Search, Breadth-First Search, Graph Theory
Medium
38
0.7%
300Find K Pairs with Smallest Sums
Array, Heap (Priority Queue)
Medium
38
0.4%
301Ransom Note
Hash Table, String, Counting
Easy
38
0.7%
302Design In-Memory File System
Hash Table, String, Design, Trie, Sorting
Hard
38
0.5%
303Number of Distinct Islands
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Sorting, Matrix, Hash Function
Medium
38
0.6%
304Shortest Path in Binary Matrix
Array, Breadth-First Search, Matrix
Medium
38
0.5%
305Longest Common Subsequence
String, Dynamic Programming
Medium
38
0.6%
306Unique Number of Occurrences
Array, Hash Table
Easy
38
0.8%
307Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Medium
38
0.6%
308Find Missing and Repeated Values
Array, Hash Table, Math, Matrix
Easy
38
0.8%
309Minimum Difference in Sums After Removal of Elements
Array, Dynamic Programming, Heap (Priority Queue)
Hard
38
0.7%
310Wildcard Matching
String, Dynamic Programming, Greedy, Recursion
Hard
37
0.3%
311Partition List
Linked List, Two Pointers
Medium
37
0.6%
312Flatten Binary Tree to Linked List
Linked List, Stack, Tree, Depth-First Search, Binary Tree
Medium
37
0.7%
313Design Add and Search Words Data Structure
String, Depth-First Search, Design, Trie
Medium
37
0.5%
314Maximal Square
Array, Dynamic Programming, Matrix
Medium
37
0.5%
315Alien Dictionary
Array, String, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
37
0.4%
316First Bad Version
Binary Search, Interactive
Easy
37
0.5%
317Increasing Triplet Subsequence
Array, Greedy
Medium
37
0.4%
318Sum of Two Integers
Math, Bit Manipulation
Medium
37
0.6%
319Diagonal Traverse
Array, Matrix, Simulation
Medium
37
0.7%
320Coin Change II
Array, Dynamic Programming
Medium
37
0.6%
321Valid Parenthesis String
String, Dynamic Programming, Stack, Greedy
Medium
37
0.4%
322Subarray Product Less Than K
Array, Binary Search, Sliding Window, Prefix Sum
Medium
37
0.5%
323First Unique Number
Array, Hash Table, Design, Queue, Data Stream
Medium
37
0.6%
324Amount of Time for Binary Tree to Be Infected
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
37
0.7%
325Maximum K to Sort a Permutation
Array, Bit Manipulation
Medium
37
0.4%
326Lexicographically Smallest Negated Permutation that Sums to Target
Array, Math, Two Pointers, Greedy, Sorting
Medium
37
0.3%
327Insert Interval
Array
Medium
36
0.5%
328Interleaving String
String, Dynamic Programming
Medium
36
0.4%
329Single Number II
Array, Bit Manipulation
Medium
36
0.7%
330Repeated Substring Pattern
String, String Matching
Easy
36
0.5%
331Swapping Nodes in a Linked List
Linked List, Two Pointers
Medium
36
0.7%
332Is Graph Bipartite?
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
36
0.6%
333Bus Routes
Array, Hash Table, Breadth-First Search
Hard
36
0.5%
334Design Circular Queue
Array, Linked List, Design, Queue
Medium
36
0.5%
335Minimum Add to Make Parentheses Valid
String, Stack, Greedy
Medium
36
0.7%
336Maximum Sum BST in Binary Tree
Dynamic Programming, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Hard
36
0.5%
337Process String with Special Operations I
String, Simulation
Medium
36
0.7%
338Text Justification
Array, String, Simulation
Hard
35
0.5%
339Distinct Subsequences
String, Dynamic Programming
Hard
35
0.5%
340Number of Connected Components in an Undirected Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
35
0.7%
341Boundary of Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
35
0.5%
342Count Binary Substrings
Two Pointers, String
Easy
35
0.7%
343Jewels and Stones
Hash Table, String
Easy
35
0.9%
344Find the Smallest Divisor Given a Threshold
Array, Binary Search
Medium
35
0.7%
345Replace Employee ID With The Unique Identifier
Database
Easy
35
0.8%
346Apply Discount to Prices
String
Medium
35
0.3%
347Most Expensive Item That Can Not Be Bought
Math, Dynamic Programming, Number Theory
Medium
35
0.8%
348Find Longest Self-Contained Substring
Hash Table, String, Sorting
Hard
35
0.6%
349Find the Number of Possible Ways for an Event
Math, Dynamic Programming, Combinatorics
Hard
35
0.4%
350Minimum Number of Primes to Sum to Target
Array, Math, Dynamic Programming, Number Theory
Medium
35
0.6%
351Substring with Concatenation of All Words
Hash Table, String, Sliding Window
Hard
34
0.3%
352Permutations II
Array, Backtracking, Sorting
Medium
34
0.6%
353Permutation Sequence
Math, Recursion
Hard
34
0.5%
354Compare Version Numbers
Two Pointers, String
Medium
34
0.5%
355Department Top Three Salaries
Database
Hard
34
0.6%
356Implement Stack using Queues
Stack, Design, Queue
Easy
34
0.7%
357Add Digits
Math, Simulation, Number Theory
Easy
34
0.7%
358Range Sum Query - Immutable
Array, Design, Prefix Sum
Easy
34
0.7%
359Burst Balloons
Array, Dynamic Programming
Hard
34
0.6%
360Remove Duplicate Letters
String, Stack, Greedy, Monotonic Stack
Medium
34
0.5%
361Find All Numbers Disappeared in an Array
Array, Hash Table
Easy
34
0.6%
362Find Eventual Safe States
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
34
0.7%
363Reorder Data in Log Files
Array, String, Sorting
Medium
34
0.6%
364Binary Tree Cameras
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
34
0.5%
365Maximum Number of Events That Can Be Attended
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
34
0.4%
366Customer Who Visited but Did Not Make Any Transactions
Database
Easy
34
0.7%
367Confirmation Rate
Database
Medium
34
0.6%
368Partition Array According to Given Pivot
Array, Two Pointers, Simulation
Medium
34
0.9%
369Create a DataFrame from ListEasy
34
0.8%
370Gray Code
Math, Backtracking, Bit Manipulation
Medium
34
0.7%
371Rank Scores
Database
Medium
34
0.7%
372Consecutive Numbers
Database
Medium
34
0.5%
373Remove Linked List Elements
Linked List, Recursion
Easy
34
0.5%
374Reconstruct Itinerary
Array, String, Depth-First Search, Graph Theory, Sorting, Heap (Priority Queue), Eulerian Circuit
Hard
34
0.4%
375Rotate Function
Array, Math, Dynamic Programming
Medium
34
0.5%
376Path Sum III
Tree, Depth-First Search, Binary Tree
Medium
34
0.5%
377Next Greater Element III
Math, Two Pointers, String
Medium
34
0.4%
378Employee Bonus
Database
Easy
34
0.8%
379Domino and Tromino Tiling
Dynamic Programming
Medium
34
0.5%
380Binary Subarrays With Sum
Array, Hash Table, Sliding Window, Prefix Sum
Medium
34
0.7%
381Minimum Falling Path Sum
Array, Dynamic Programming, Matrix
Medium
34
0.6%
382Customers Who Bought All Products
Database
Medium
34
0.6%
383Smallest Subsequence of Distinct Characters
String, Stack, Greedy, Monotonic Stack
Medium
34
0.6%
384Replace Elements with Greatest Element on Right Side
Array
Easy
34
0.7%
385Balance a Binary Search Tree
Divide and Conquer, Greedy, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
34
0.9%
386Remove All Adjacent Duplicates in String II
String, Stack
Medium
34
0.6%
387Make Sum Divisible by P
Array, Hash Table, Prefix Sum
Medium
34
0.4%
388Removing Stars From a String
String, Stack, Simulation
Medium
34
0.8%
389Put Marbles in Bags
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
34
0.7%
390Make String a Subsequence Using Cyclic Increments
Two Pointers, String
Medium
34
0.7%
391Minimum Number of Pushes to Type Word II
Hash Table, String, Greedy, Sorting, Counting
Medium
34
0.8%
392Count Square Submatrices with All Ones
Array, Dynamic Programming, Matrix
Medium
34
0.8%
393Binary Search Tree Iterator
Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator
Medium
33
0.8%
394Dungeon Game
Array, Dynamic Programming, Matrix
Hard
33
0.4%
395Nth Highest Salary
Database
Medium
33
0.4%
396H-Index
Array, Sorting, Counting Sort
Medium
33
0.4%
397Longest Substring with At Least K Repeating Characters
Hash Table, String, Divide and Conquer, Sliding Window
Medium
33
0.5%
398Frog Jump
Array, Dynamic Programming
Hard
33
0.5%
399Third Maximum Number
Array, Sorting
Easy
33
0.4%
400Predict the Winner
Array, Math, Dynamic Programming, Recursion, Game Theory
Medium
33
0.6%
401Merge Two Binary Trees
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
33
0.8%
402Two Sum IV - Input is a BST
Hash Table, Two Pointers, Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
33
0.6%
403Find Pivot Index
Array, Prefix Sum
Easy
33
0.6%
404Split Linked List in Parts
Linked List
Medium
33
0.7%
405Construct Binary Search Tree from Preorder Traversal
Array, Stack, Tree, Binary Search Tree, Monotonic Stack, Binary Tree
Medium
33
0.8%
406Immediate Food Delivery II
Database
Medium
33
0.6%
407Students and Examinations
Database
Easy
33
0.6%
408Maximum Average Pass Ratio
Array, Greedy, Heap (Priority Queue)
Medium
33
0.7%
409Substring With Largest Variance
Hash Table, String, Dynamic Programming, Enumeration
Hard
33
0.5%
410Using a Robot to Print the Lexicographically Smallest String
Hash Table, String, Stack, Greedy
Medium
33
0.6%
411Kth Largest Sum in a Binary Tree
Tree, Breadth-First Search, Sorting, Binary Tree
Medium
33
0.6%
412Distribute Candies Among Children II
Math, Combinatorics, Enumeration
Medium
33
0.6%
413Maximum Number of Groups With Increasing Length
Array, Math, Binary Search, Greedy, Sorting
Hard
33
0.2%
414Minimum Operations to Make Array Non Decreasing
Array, Greedy
Medium
33
0.6%
415Multiply Strings
Math, String, Simulation
Medium
32
0.4%
416Unique Binary Search Trees
Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree
Medium
32
0.6%
417Path Sum
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
32
0.6%
418Excel Sheet Column Title
Math, String
Easy
32
0.5%
419Different Ways to Add Parentheses
Math, String, Dynamic Programming, Recursion, Memoization
Medium
32
0.7%
420Kth Smallest Element in a Sorted Matrix
Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
Medium
32
0.6%
421Add Strings
Math, String, Simulation
Easy
32
0.5%
422Image Smoother
Array, Matrix
Easy
32
0.7%
423Baseball Game
Array, Stack, Simulation
Easy
32
0.8%
424Flatten a Multilevel Doubly Linked List
Linked List, Depth-First Search, Doubly-Linked List
Medium
32
0.6%
425Custom Sort String
Hash Table, String, Sorting
Medium
32
0.7%
426Minimum Number of Refueling Stops
Array, Dynamic Programming, Greedy, Heap (Priority Queue)
Hard
32
0.4%
427Binary Search Tree to Greater Sum Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
32
0.9%
428Remove All Adjacent Duplicates In String
String, Stack
Easy
32
0.7%
429Product Sales Analysis I
Database
Easy
32
0.9%
430Number of Equivalent Domino Pairs
Array, Hash Table, Counting
Easy
32
0.6%
431Angle Between Hands of a Clock
Math
Medium
32
0.7%
432Count Negative Numbers in a Sorted Matrix
Array, Binary Search, Matrix
Easy
32
0.8%
433Path Crossing
Hash Table, String
Easy
32
0.6%
434Magnetic Force Between Two Balls
Array, Binary Search, Sorting
Medium
32
0.7%
435Sum of Beauty of All Substrings
Hash Table, String, Counting
Medium
32
0.7%
436Sum of All Subset XOR Totals
Array, Math, Backtracking, Bit Manipulation, Combinatorics, Enumeration
Easy
32
0.9%
437Count Number of Rectangles Containing Each Point
Array, Hash Table, Binary Search, Binary Indexed Tree, Sorting
Medium
32
0.4%
438Best Poker Hand
Array, Hash Table, Counting
Easy
32
0.6%
439Max Sum of a Pair With Equal Sum of Digits
Array, Hash Table, Sorting, Heap (Priority Queue)
Medium
32
0.7%
440Maximum Number of Books You Can Take
Array, Dynamic Programming, Stack, Monotonic Stack
Hard
32
0.4%
441Maximum Coins From K Consecutive Bags
Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
Medium
32
0.3%
442Count Bowl Subarrays
Array, Stack, Monotonic Stack
Medium
32
0.5%
443Sell Diminishing-Valued Colored Balls
Array, Math, Binary Search, Greedy, Sorting, Heap (Priority Queue)
Medium
32
0.3%
444Longest Arithmetic Sequence After Changing At Most One Element
Array, Enumeration
Medium
32
0.2%
445Spiral Matrix II
Array, Matrix, Simulation
Medium
30
0.8%
446Combinations
Backtracking
Medium
30
0.7%
447Best Time to Buy and Sell Stock III
Array, Dynamic Programming
Hard
30
0.5%
448Palindrome Partitioning II
String, Dynamic Programming
Hard
30
0.4%
449Customers Who Never Order
Database
Easy
30
0.7%
450Reverse Bits
Divide and Conquer, Bit Manipulation
Easy
30
0.7%
451Summary Ranges
Array
Easy
30
0.5%
452Find All Duplicates in an Array
Array, Hash Table, Sorting
Medium
30
0.8%
453Maximum Length of Pair Chain
Array, Dynamic Programming, Greedy, Sorting
Medium
30
0.6%
454Loud and Rich
Array, Depth-First Search, Graph Theory, Topological Sort
Medium
30
0.6%
455Sort Array By Parity II
Array, Two Pointers, Sorting
Easy
30
0.7%
456Flip String to Monotone Increasing
String, Dynamic Programming
Medium
30
0.6%
457Remove Outermost Parentheses
String, Stack
Easy
30
0.9%
458Recover a Tree From Preorder Traversal
String, Tree, Depth-First Search, Binary Tree
Hard
30
0.8%
459Longest Duplicate Substring
String, Binary Search, Sliding Window, Rolling Hash, Suffix Array, Hash Function
Hard
30
0.3%
460Shortest Path with Alternating Colors
Breadth-First Search, Graph Theory
Medium
30
0.5%
461Shortest Path in a Grid with Obstacles Elimination
Array, Breadth-First Search, Matrix
Hard
30
0.5%
462Minimum Cost to Cut a Stick
Array, Dynamic Programming, Sorting
Hard
30
0.6%
463Design an Expression Tree With Evaluate Function
Array, Math, Stack, Tree, Design, Binary Tree
Medium
30
0.8%
464Find Minimum Time to Finish All Jobs
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Hard
30
0.5%
465The Number of the Smallest Unoccupied Chair
Array, Hash Table, Heap (Priority Queue)
Medium
30
0.6%
466Minimum Swaps to Group All 1's Together II
Array, Sliding Window
Medium
30
0.7%
467Number of Ways to Split Array
Array, Prefix Sum
Medium
30
0.6%
468Move Pieces to Obtain a String
Two Pointers, String
Medium
30
0.6%
469Cousins in Binary Tree II
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
30
0.8%
470Length of Longest V-Shaped Diagonal Segment
Array, Dynamic Programming, Memoization, Matrix
Hard
30
0.6%
471Path Sum II
Backtracking, Tree, Depth-First Search, Binary Tree
Medium
29
0.6%
472Pascal's Triangle II
Array, Dynamic Programming
Easy
29
0.7%
473Shortest Palindrome
String, Rolling Hash, String Matching, Hash Function
Hard
29
0.4%
474Meeting Rooms
Array, Sorting
Easy
29
0.6%
475Perfect Squares
Math, Dynamic Programming, Breadth-First Search
Medium
29
0.6%
476Find the Difference
Hash Table, String, Bit Manipulation, Sorting
Easy
29
0.6%
477All O`one Data Structure
Hash Table, Linked List, Design, Doubly-Linked List
Hard
29
0.4%
478132 Pattern
Array, Binary Search, Stack, Monotonic Stack, Ordered Set
Medium
29
0.3%
479Most Frequent Subtree Sum
Hash Table, Tree, Depth-First Search, Binary Tree
Medium
29
0.7%
480Convert BST to Greater Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
29
0.7%
481Lemonade Change
Array, Greedy
Easy
29
0.6%
482Minimum Cost For Tickets
Array, Dynamic Programming
Medium
29
0.7%
483Interval List Intersections
Array, Two Pointers, Sweep Line
Medium
29
0.7%
484Maximum Difference Between Node and Ancestor
Tree, Depth-First Search, Binary Tree
Medium
29
0.8%
485Actors and Directors Who Cooperated At Least Three Times
Database
Easy
29
0.7%
486Shortest Common Supersequence
String, Dynamic Programming
Hard
29
0.6%
487Sales Analysis III
Database
Easy
29
0.5%
488Number of Dice Rolls With Target Sum
Dynamic Programming
Medium
29
0.6%
489List the Products Ordered in a Period
Database
Easy
29
0.7%
490Shuffle the Array
Array
Easy
29
0.9%
491Clone Binary Tree With Random Pointer
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
29
0.8%
492Shortest Subarray to be Removed to Make Array Sorted
Array, Two Pointers, Binary Search, Stack, Monotonic Stack
Medium
29
0.5%
493Lowest Common Ancestor of a Binary Tree IV
Hash Table, Tree, Depth-First Search, Binary Tree
Medium
29
0.8%
494Find the Highest Altitude
Array, Prefix Sum
Easy
29
0.8%
495Determine Whether Matrix Can Be Obtained By Rotation
Array, Matrix
Easy
29
0.7%
496Count Number of Pairs With Absolute Difference K
Array, Hash Table, Counting
Easy
29
0.9%
497GCD Sort of an Array
Array, Math, Union-Find, Sorting, Number Theory
Hard
29
0.5%
498Partition Array Into Two Arrays to Minimize Sum Difference
Array, Two Pointers, Binary Search, Dynamic Programming, Bit Manipulation, Sorting, Ordered Set, Bitmask
Hard
29
0.2%
499Number of Ways to Select Buildings
String, Dynamic Programming, Prefix Sum
Medium
29
0.5%
500Total Appeal of A String
Hash Table, String, Dynamic Programming
Hard
29
0.6%
501Minimum Rounds to Complete All Tasks
Array, Hash Table, Greedy, Counting
Medium
29
0.6%
502Partition Array Such That Maximum Difference Is K
Array, Greedy, Sorting
Medium
29
0.8%
503Count Unreachable Pairs of Nodes in an Undirected Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
29
0.5%
504Smallest Number in Infinite Set
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
29
0.7%
505Maximum Number of Robots Within Budget
Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue
Hard
29
0.4%
506Construct Smallest Number From DI String
String, Backtracking, Stack, Greedy
Medium
29
0.9%
507Find the K-Sum of an Array
Array, Sorting, Heap (Priority Queue)
Hard
29
0.4%
508Minimum Adjacent Swaps to Make a Valid Array
Array, Greedy
Medium
29
0.7%
509Meeting Rooms III
Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
Hard
29
0.5%
510Strictly Palindromic Number
Math, Two Pointers, Brainteaser
Medium
29
0.9%
511Minimum Number of Operations to Sort a Binary Tree by Level
Tree, Breadth-First Search, Binary Tree
Medium
29
0.7%
512Design Memory Allocator
Array, Hash Table, Design, Simulation
Medium
29
0.5%
513Count the Number of Special Characters I
Hash Table, String
Easy
29
0.8%
514Maximum Sum With at Most K Elements
Array, Greedy, Sorting, Heap (Priority Queue), Matrix
Medium
29
0.6%
515Minimum Operations to Make the Array Alternating
Array, Hash Table, Greedy, Counting
Medium
29
0.4%
516Count Subarrays With Median K
Array, Hash Table, Prefix Sum
Hard
29
0.5%
517Minimum Swaps to Avoid Forbidden Values
Array, Hash Table, Greedy, Counting
Hard
29
0.3%
518Divide an Array Into Subarrays With Minimum Cost I
Array, Sorting, Enumeration
Easy
29
0.8%
519Duplicate Emails
Database
Easy
28
0.7%
520Reverse Words in a String II
Two Pointers, String
Medium
28
0.6%
521Repeated DNA Sequences
Hash Table, String, Bit Manipulation, Sliding Window, Rolling Hash, Hash Function
Medium
28
0.5%
522Combination Sum III
Array, Backtracking
Medium
28
0.7%
523Find the Celebrity
Two Pointers, Graph Theory, Interactive
Medium
28
0.5%
524Longest Increasing Path in a Matrix
Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Memoization, Matrix
Hard
28
0.6%
525Arranging Coins
Math, Binary Search
Easy
28
0.5%
526Serialize and Deserialize BST
String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Search Tree, Binary Tree
Medium
28
0.6%
527Heaters
Array, Two Pointers, Binary Search, Sorting
Medium
28
0.4%
528Super Washing Machines
Array, Greedy
Hard
28
0.4%
529Continuous Subarray Sum
Array, Hash Table, Math, Prefix Sum
Medium
28
0.3%
530Minesweeper
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
28
0.7%
531K-diff Pairs in an Array
Array, Hash Table, Two Pointers, Binary Search, Sorting
Medium
28
0.5%
532Encode and Decode TinyURL
Hash Table, String, Design, Hash Function
Medium
28
0.9%
533Reverse Words in a String III
Two Pointers, String
Easy
28
0.8%
534Array Partition
Array, Greedy, Sorting, Counting Sort
Easy
28
0.8%
535Exchange Seats
Database
Medium
28
0.7%
536Number of Distinct Islands II
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Sorting, Matrix, Hash Function
Hard
28
0.6%
537Most Common Word
Array, Hash Table, String, Counting
Easy
28
0.5%
538Keys and Rooms
Depth-First Search, Breadth-First Search, Graph Theory
Medium
28
0.8%
539Car Fleet
Array, Stack, Sorting, Monotonic Stack
Medium
28
0.6%
540Orderly Queue
Math, String, Sorting
Hard
28
0.7%
541Most Stones Removed with Same Row or Column
Hash Table, Depth-First Search, Union-Find, Graph Theory
Medium
28
0.6%
542Sum of Root To Leaf Binary Numbers
Tree, Depth-First Search, Binary Tree
Easy
28
0.8%
543Uncrossed Lines
Array, Dynamic Programming
Medium
28
0.7%
544Last Stone Weight
Array, Heap (Priority Queue)
Easy
28
0.7%
545Product Price at a Given Date
Database
Medium
28
0.6%
546Reformat Department Table
Database
Easy
28
0.8%
547Maximum Score Words Formed by Letters
Array, Hash Table, String, Dynamic Programming, Backtracking, Bit Manipulation, Counting, Bitmask
Hard
28
0.8%
548Fair Distribution of Cookies
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
28
0.7%
549Count Number of Teams
Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
Medium
28
0.7%
550Allocate Mailboxes
Array, Math, Dynamic Programming, Sorting
Hard
28
0.6%
551Min Cost to Connect All Points
Array, Union-Find, Graph Theory, Minimum Spanning Tree
Medium
28
0.7%
552Concatenation of Consecutive Binary Numbers
Math, Bit Manipulation, Simulation
Medium
28
0.7%
553Number of Students Unable to Eat Lunch
Array, Stack, Queue, Simulation
Easy
28
0.8%
554Maximum Erasure Value
Array, Hash Table, Sliding Window
Medium
28
0.6%
555Unique Length-3 Palindromic Subsequences
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
28
0.7%
556Find if Path Exists in Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Easy
28
0.6%
557Find All Possible Recipes from Given Supplies
Array, Hash Table, String, Graph Theory, Topological Sort
Medium
28
0.6%
558Number of Smooth Descent Periods of a Stock
Array, Math, Two Pointers, Dynamic Programming, Sliding Window
Medium
28
0.7%
559Count the Hidden Sequences
Array, Prefix Sum
Medium
28
0.6%
560Minimum Sum of Four Digit Number After Splitting Digits
Math, Greedy, Sorting
Easy
28
0.9%
561Minimum Sum of Squared Difference
Array, Binary Search, Greedy, Sorting, Heap (Priority Queue)
Medium
28
0.3%
562Optimal Partition of String
Hash Table, String, Greedy
Medium
28
0.8%
563Remove Nodes From Linked List
Linked List, Stack, Recursion, Monotonic Stack
Medium
28
0.8%
564To Be Or Not To BeEasy
28
0.6%
565Count Stepping Numbers in Range
String, Dynamic Programming
Hard
28
0.3%
566Count Beautiful Substrings I
Hash Table, Math, String, Enumeration, Number Theory, Prefix Sum
Medium
28
0.6%
567Maximize Happiness of Selected Children
Array, Greedy, Sorting
Medium
28
0.6%
568Generate Binary Strings Without Adjacent Zeros
String, Backtracking, Bit Manipulation
Medium
28
0.9%
569N-Queens II
Backtracking
Hard
27
0.8%
570Valid Number
String
Hard
27
0.2%
571Sum Root to Leaf Numbers
Tree, Depth-First Search, Binary Tree
Medium
27
0.7%
572Max Points on a Line
Array, Hash Table, Math, Geometry
Hard
27
0.3%
573Number of 1 Bits
Divide and Conquer, Bit Manipulation
Easy
27
0.8%
574Number of Digit One
Math, Dynamic Programming, Recursion
Hard
27
0.4%
575Ugly Number
Math
Easy
27
0.4%
576Binary Tree Vertical Order Traversal
Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
Medium
27
0.6%
577Bulb Switcher
Math, Brainteaser
Medium
27
0.6%
578Counting Bits
Dynamic Programming, Bit Manipulation
Easy
27
0.8%
579Flatten Nested List Iterator
Stack, Tree, Depth-First Search, Design, Queue, Iterator
Medium
27
0.7%
580Logger Rate Limiter
Hash Table, Design, Data Stream
Easy
27
0.8%
581Design Hit Counter
Array, Binary Search, Design, Queue, Data Stream
Medium
27
0.7%
582Longest Palindrome
Hash Table, String, Greedy
Easy
27
0.6%
583Minimum Genetic Mutation
Hash Table, String, Breadth-First Search
Medium
27
0.6%
584Maximum Alternating Subarray Sum
Array, Dynamic Programming
Medium
27
0.4%
585Subtree of Another Tree
Tree, Depth-First Search, String Matching, Binary Tree, Hash Function
Easy
27
0.5%
586Solve the Equation
Math, String, Simulation
Medium
27
0.5%
587Cut Off Trees for Golf Event
Array, Breadth-First Search, Heap (Priority Queue), Matrix
Hard
27
0.4%
588Redundant Connection
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
27
0.7%
589Partition to K Equal Sum Subsets
Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
Medium
27
0.4%
590Find K-th Smallest Pair Distance
Array, Two Pointers, Binary Search, Sorting
Hard
27
0.5%
591Network Delay Time
Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
27
0.6%
592All Paths From Source to Target
Backtracking, Depth-First Search, Breadth-First Search, Graph Theory
Medium
27
0.8%
593Backspace String Compare
Two Pointers, String, Stack, Simulation
Easy
27
0.5%
594Shortest Subarray with Sum at Least K
Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue
Hard
27
0.3%
595Find and Replace Pattern
Array, Hash Table, String
Medium
27
0.8%
596Maximum Sum Circular Subarray
Array, Divide and Conquer, Dynamic Programming, Queue, Monotonic Queue
Medium
27
0.5%
597Number of Recent Calls
Design, Queue, Data Stream
Easy
27
0.8%
598Subarray Sums Divisible by K
Array, Hash Table, Prefix Sum
Medium
27
0.6%
599Longest Repeating Substring
String, Binary Search, Dynamic Programming, Rolling Hash, Suffix Array, Hash Function
Medium
27
0.6%
600High Five
Array, Hash Table, Sorting, Heap (Priority Queue)
Easy
27
0.7%
601Two Sum Less Than K
Array, Two Pointers, Binary Search, Sorting
Easy
27
0.6%
602Path With Maximum Minimum Value
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Medium
27
0.5%
603Design File System
Hash Table, String, Design, Trie
Medium
27
0.7%
604Distant Barcodes
Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
27
0.5%
605Two Sum BSTs
Two Pointers, Binary Search, Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
27
0.7%
606Sum of Nodes with Even-Valued Grandparent
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
27
0.9%
607Get Watched Videos by Your Friends
Array, Hash Table, Breadth-First Search, Graph Theory, Sorting
Medium
27
0.5%
608Number of Operations to Make Network Connected
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
27
0.7%
609Remove Palindromic Subsequences
Two Pointers, String
Easy
27
0.8%
610The K Weakest Rows in a Matrix
Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
Easy
27
0.7%
611How Many Numbers Are Smaller Than the Current Number
Array, Hash Table, Sorting, Counting Sort
Easy
27
0.9%
612Check If Array Pairs Are Divisible by k
Array, Hash Table, Counting
Medium
27
0.5%
613Can Make Arithmetic Progression From Sequence
Array, Sorting
Easy
27
0.7%
614Max Number of K-Sum Pairs
Array, Hash Table, Two Pointers, Sorting
Medium
27
0.6%
615Minimum Length of String After Deleting Similar Ends
Two Pointers, String
Medium
27
0.6%
616Maximum Element After Decreasing and Rearranging
Array, Greedy, Sorting
Medium
27
0.7%
617Next Palindrome Using Same Digits
Two Pointers, String
Hard
27
0.5%
618Largest Odd Number in String
Math, String, Greedy
Easy
27
0.7%
619Check for Contradictions in Equations
Array, String, Depth-First Search, Union-Find, Graph Theory
Hard
27
0.4%
620Find Missing Observations
Array, Math, Simulation
Medium
27
0.6%
621Number of Laser Beams in a Bank
Array, Math, String, Matrix
Medium
27
0.9%
622Maximize Number of Subsequences in a String
String, Greedy, Prefix Sum
Medium
27
0.4%
623K Divisible Elements Subarrays
Array, Hash Table, Trie, Rolling Hash, Hash Function, Enumeration
Medium
27
0.6%
624Minimum Average Difference
Array, Prefix Sum
Medium
27
0.4%
625Count Number of Texts
Hash Table, Math, String, Dynamic Programming
Medium
27
0.5%
626Maximum Consecutive Floors Without Special Floors
Array, Sorting
Medium
27
0.5%
627Maximum Bags With Full Capacity of Rocks
Array, Greedy, Sorting
Medium
27
0.7%
628Design a Text Editor
Linked List, String, Stack, Design, Simulation, Doubly-Linked List
Hard
27
0.5%
629Design a Food Rating System
Array, Hash Table, String, Design, Heap (Priority Queue), Ordered Set
Medium
27
0.5%
630Product Sales Analysis IV
Database
Medium
27
0.8%
631Maximum Matching of Players With Trainers
Array, Two Pointers, Greedy, Sorting
Medium
27
0.8%
632Smallest Subarrays With Maximum Bitwise OR
Array, Binary Search, Bit Manipulation, Sliding Window
Medium
27
0.6%
633Split With Minimum Sum
Math, Greedy, Sorting
Easy
27
0.7%
634Find the Divisibility Array of a String
Array, Math, String
Medium
27
0.4%
635Row With Maximum Ones
Array, Matrix
Easy
27
0.7%
636Count Zero Request Servers
Array, Hash Table, Sliding Window, Sorting
Medium
27
0.4%
637Maximize the Profit as the Salesman
Array, Hash Table, Binary Search, Dynamic Programming, Sorting
Medium
27
0.4%
638Minimum Number of Operations to Make Array Empty
Array, Hash Table, Greedy, Counting
Medium
27
0.6%
639Find Maximum Non-decreasing Array Length
Array, Binary Search, Dynamic Programming, Stack, Queue, Monotonic Stack, Prefix Sum, Monotonic Queue
Hard
27
0.2%
640Most Frequent IDs
Array, Hash Table, Heap (Priority Queue), Ordered Set
Medium
27
0.4%
641Minimum Array Sum
Array, Dynamic Programming
Medium
27
0.3%
642Minimum Number of Operations to Make Elements in Array Distinct
Array, Hash Table
Easy
27
0.7%
643Substring Matching Pattern
String, String Matching
Easy
27
0.3%
644Check If Digits Are Equal in String After Operations I
Math, String, Simulation, Combinatorics, Number Theory
Easy
27
0.8%
645Count Covered Buildings
Array, Hash Table, Sorting
Medium
27
0.6%
646Maximum Total from Optimal Activation Order
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue)
Medium
27
0.3%
647Trionic Array I
Array
Easy
27
0.5%
648Minimum Removals to Balance Array
Array, Binary Search, Sliding Window, Sorting
Medium
27
0.5%
649Maximize Fixed Points After Deletions
Array, Binary Search, Sorting
Hard
27
0.2%
650Restore IP Addresses
String, Backtracking
Medium
25
0.6%
651Unique Binary Search Trees II
Dynamic Programming, Backtracking, Tree, Binary Search Tree, Binary Tree
Medium
25
0.6%
652Department Highest Salary
Database
Medium
25
0.6%
653Walls and Gates
Array, Breadth-First Search, Matrix
Medium
25
0.6%
654Power of Three
Math, Recursion
Easy
25
0.5%
655Nested List Weight Sum
Depth-First Search, Breadth-First Search
Medium
25
0.9%
656Moving Average from Data Stream
Array, Design, Queue, Data Stream
Easy
25
0.8%
657Insert Delete GetRandom O(1) - Duplicates allowed
Array, Hash Table, Math, Design, Randomized
Hard
25
0.4%
658Lexicographical Numbers
Depth-First Search, Trie
Medium
25
0.8%
659Battleships in a Board
Array, Depth-First Search, Matrix
Medium
25
0.8%
660Optimal Division
Array, Math, Dynamic Programming
Medium
25
0.6%
661Construct String from Binary Tree
String, Tree, Depth-First Search, Binary Tree
Medium
25
0.7%
662Triangle Judgement
Database
Easy
25
0.7%
663Design Search Autocomplete System
String, Depth-First Search, Design, Trie, Sorting, Heap (Priority Queue), Data Stream
Hard
25
0.5%
664My Calendar I
Array, Binary Search, Design, Segment Tree, Ordered Set
Medium
25
0.6%
665Monotone Increasing Digits
Math, Greedy
Medium
25
0.5%
666Delete and Earn
Array, Hash Table, Dynamic Programming
Medium
25
0.6%
667Serialize and Deserialize N-ary Tree
String, Tree, Depth-First Search, Breadth-First Search
Hard
25
0.7%
668Insert into a Binary Search Tree
Tree, Binary Search Tree, Binary Tree
Medium
25
0.7%
669Swim in Rising Water
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Hard
25
0.7%
670Minimum Swaps To Make Sequences Increasing
Array, Dynamic Programming
Hard
25
0.4%
671Split Array into Fibonacci Sequence
String, Backtracking
Medium
25
0.4%
672Maximum Frequency Stack
Hash Table, Stack, Design, Ordered Set
Hard
25
0.7%
673Prison Cells After N Days
Array, Hash Table, Math, Bit Manipulation
Medium
25
0.4%
674Unique Paths III
Array, Backtracking, Bit Manipulation, Matrix
Hard
25
0.8%
675Missing Element in Sorted Array
Array, Binary Search
Medium
25
0.6%
676Connecting Cities With Minimum Cost
Union-Find, Graph Theory, Heap (Priority Queue), Minimum Spanning Tree
Medium
25
0.6%
677Find Words That Can Be Formed by Characters
Array, Hash Table, String, Counting
Easy
25
0.7%
678Insufficient Nodes in Root to Leaf Paths
Tree, Depth-First Search, Binary Tree
Medium
25
0.6%
679Handshakes That Don't Cross
Math, Dynamic Programming
Hard
25
0.6%
680Closest Divisors
Math
Medium
25
0.6%
681Minimum Garden Perimeter to Collect Enough Apples
Math, Binary Search
Medium
25
0.6%
682All Elements in Two Binary Search Trees
Tree, Depth-First Search, Binary Search Tree, Sorting, Binary Tree
Medium
25
0.8%
683Delete Leaves With a Given Value
Tree, Depth-First Search, Binary Tree
Medium
25
0.8%
684Number of Steps to Reduce a Number in Binary Representation to One
String, Bit Manipulation, Simulation
Medium
25
0.6%
685String Matching in an Array
Array, String, String Matching
Easy
25
0.7%
686NPV Queries
Database
Easy
25
0.8%
687Design Browser History
Array, Linked List, Stack, Design, Doubly-Linked List, Data Stream
Medium
25
0.8%
688Sales by Day of the Week
Database
Hard
25
0.8%
689Maximum Number of Non-Overlapping Substrings
Hash Table, String, Greedy, Sorting
Hard
25
0.4%
690Customer Order Frequency
Database
Easy
25
0.7%
691Find the Index of the Large Integer
Array, Binary Search, Interactive
Medium
25
0.6%
692Warehouse Manager
Database
Easy
25
0.9%
693Maximum Number of Achievable Transfer Requests
Array, Backtracking, Bit Manipulation, Enumeration
Hard
25
0.6%
694Minimum Operations to Reduce X to Zero
Array, Hash Table, Binary Search, Sliding Window, Prefix Sum
Medium
25
0.4%
695Decode XORed Permutation
Array, Bit Manipulation
Medium
25
0.7%
696Form Array by Concatenating Subarrays of Another Array
Array, Two Pointers, Greedy, String Matching
Medium
25
0.5%
697The Number of Employees Which Report to Each Employee
Database
Easy
25
0.5%
698Find Distance in a Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
25
0.7%
699Minimum Degree of a Connected Trio in a Graph
Graph Theory, Enumeration
Hard
25
0.4%
700Closest Room
Array, Binary Search, Sorting, Ordered Set
Hard
25
0.4%
701Build Array from Permutation
Array, Simulation
Easy
25
0.9%
702Longest Common Subpath
Array, Binary Search, Rolling Hash, Suffix Array, Hash Function
Hard
25
0.3%
703Check if Move is Legal
Array, Matrix, Enumeration
Medium
25
0.5%
704Sum of Beauty in the Array
Array
Medium
25
0.5%
705Kth Distinct String in an Array
Array, Hash Table, String, Counting
Easy
25
0.8%
706Decode the Slanted Ciphertext
String, Simulation
Medium
25
0.7%
707Find Good Days to Rob the Bank
Array, Dynamic Programming, Prefix Sum
Medium
25
0.5%
708Adding Spaces to a String
Array, Two Pointers, String, Simulation
Medium
25
0.7%
709Replace Non-Coprime Numbers in Array
Array, Math, Stack, Number Theory
Hard
25
0.6%
710Replace Elements in an Array
Array, Hash Table, Simulation
Medium
25
0.6%
711Minimum Score After Removals on a Tree
Array, Bit Manipulation, Tree, Depth-First Search
Hard
25
0.8%
712Minimum Number of Keypresses
Hash Table, String, Greedy, Sorting, Counting
Medium
25
0.7%
713Find Minimum Time to Finish All Jobs II
Array, Greedy, Sorting
Medium
25
0.7%
714Valid Palindrome IV
Two Pointers, String
Medium
25
0.8%
715Sum of Number and Its Reverse
Math, Enumeration
Medium
25
0.5%
716Design SQL
Array, Hash Table, String, Design
Medium
25
0.6%
717Append Characters to String to Make Subsequence
Two Pointers, String, Greedy
Medium
25
0.7%
718Maximum Star Sum of a Graph
Array, Greedy, Graph Theory, Sorting, Heap (Priority Queue)
Medium
25
0.4%
719Difference Between Ones and Zeros in Row and Column
Array, Matrix, Simulation
Medium
25
0.8%
720Customers With Strictly Increasing Purchases
Database
Hard
25
0.5%
721Time Taken to Cross the Door
Array, Queue, Simulation
Hard
25
0.5%
722Count the Number of Fair Pairs
Array, Two Pointers, Binary Search, Sorting
Medium
25
0.5%
723Double a Number Represented as a Linked List
Linked List, Math, Stack
Medium
25
0.6%
724Length of the Longest Valid Substring
Array, Hash Table, String, Sliding Window
Hard
25
0.4%
725Find the K-or of an Array
Array, Bit Manipulation
Easy
25
0.7%
726Find Number of Coins to Place in Tree Nodes
Dynamic Programming, Tree, Depth-First Search, Sorting, Heap (Priority Queue)
Hard
25
0.4%
727Minimum Number of Coins to be Added
Array, Greedy, Sorting
Medium
25
0.6%
728Minimum Number of Pushes to Type Word I
Math, String, Greedy
Easy
25
0.7%
729Replace Question Marks in String to Minimize Its Value
Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
25
0.3%
730Find Number of Ways to Reach the K-th Stair
Math, Dynamic Programming, Bit Manipulation, Memoization, Combinatorics
Hard
25
0.4%
731Design an Array Statistics Tracker
Hash Table, Binary Search, Design, Queue, Heap (Priority Queue), Data Stream, Ordered Set
Hard
25
0.4%
732Minimum Number of Moves to Make Palindrome
Two Pointers, String, Greedy, Binary Indexed Tree
Hard
25
0.5%
733Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values
Array, Hash Table, Greedy, Sorting, Heap (Priority Queue)
Medium
25
0.6%
734Maximum Bitwise AND After Increment Operations
Array, Greedy, Bit Manipulation, Sorting
Hard
25
0.3%
735Minimum Operations to Sort a String
String
Medium
25
0.2%
736Construct Binary Tree from Inorder and Postorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
24
0.7%
737Delete Duplicate Emails
Database
Easy
24
0.7%
738The Skyline Problem
Array, Divide and Conquer, Binary Indexed Tree, Segment Tree, Sweep Line, Sorting, Heap (Priority Queue), Ordered Set
Hard
24
0.5%
739Game of Life
Array, Matrix, Simulation
Medium
24
0.7%
740Word Pattern
Hash Table, String
Easy
24
0.4%
741Bulls and Cows
Hash Table, String, Counting
Medium
24
0.5%
742Largest Divisible Subset
Array, Math, Dynamic Programming, Sorting
Medium
24
0.5%
743Valid Word Abbreviation
Two Pointers, String
Easy
24
0.4%
744IPO
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
24
0.5%
745Construct Binary Tree from String
String, Stack, Tree, Depth-First Search, Binary Tree
Medium
24
0.6%
746Complex Number Multiplication
Math, String, Simulation
Medium
24
0.7%
747Reverse String II
Two Pointers, String
Easy
24
0.5%
748Find Cumulative Salary of an Employee
Database
Hard
24
0.5%
749Valid Triangle Number
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
24
0.6%
7502 Keys Keyboard
Math, Dynamic Programming
Medium
24
0.6%
751Equal Tree Partition
Tree, Depth-First Search, Binary Tree
Medium
24
0.4%
752Maximum Swap
Math, Greedy
Medium
24
0.5%
753Max Stack
Linked List, Stack, Design, Doubly-Linked List, Ordered Set
Hard
24
0.5%
754Closest Leaf in a Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
24
0.5%
755Prime Number of Set Bits in Binary Representation
Math, Bit Manipulation
Easy
24
0.8%
756Global and Local Inversions
Array, Math
Medium
24
0.4%
757Split BST
Tree, Binary Search Tree, Recursion, Binary Tree
Medium
24
0.8%
758Design Linked List
Linked List, Design
Medium
24
0.3%
759Numbers At Most N Given Digit Set
Array, Math, String, Binary Search, Dynamic Programming
Hard
24
0.5%
760Shortest Bridge
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
24
0.6%
761Distribute Coins in Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
24
0.8%
762Digit Count in Range
Math, Dynamic Programming
Hard
24
0.5%
763Index Pairs of a String
Array, String, Trie, Sorting
Easy
24
0.7%
764Sum of Digits in the Minimum Number
Array, Math
Easy
24
0.8%
765Find K-Length Substrings With No Repeated Characters
Hash Table, String, Sliding Window
Medium
24
0.8%
766Number of Days in a Month
Math
Easy
24
0.6%
767Remove Vowels from a String
String
Easy
24
0.9%
768Armstrong Number
Math
Easy
24
0.8%
769Maximum Average Subtree
Tree, Depth-First Search, Binary Tree
Medium
24
0.7%
770Largest Unique Number
Array, Hash Table, Sorting
Easy
24
0.7%
771Number of Submatrices That Sum to Target
Array, Hash Table, Matrix, Prefix Sum
Hard
24
0.7%
772Product Sales Analysis II
Database
Easy
24
0.8%
773Sales Analysis I
Database
Easy
24
0.7%
774Sales Analysis II
Database
Easy
24
0.5%
775Find in Mountain Array
Array, Binary Search, Interactive
Hard
24
0.4%
776Parsing A Boolean Expression
String, Stack, Recursion
Hard
24
0.7%
777Remove Covered Intervals
Array, Sorting
Medium
24
0.6%
778User Activity for the Past 30 Days I
Database
Easy
24
0.5%
779Snapshot Array
Array, Hash Table, Binary Search, Design
Medium
24
0.4%
780Largest Multiple of Three
Array, Math, Dynamic Programming, Greedy, Sorting
Hard
24
0.3%
781Prime Arrangements
Math
Easy
24
0.6%
782Diet Plan Performance
Array, Sliding Window
Easy
24
0.6%
783Maximum Subarray Sum with One Deletion
Array, Dynamic Programming
Medium
24
0.5%
784Shift 2D Grid
Array, Matrix, Simulation
Easy
24
0.7%
785Find the Team Size
Database
Easy
24
0.9%
786Restaurant Growth
Database
Medium
24
0.6%
787Number of Substrings Containing All Three Characters
Hash Table, String, Sliding Window
Medium
24
0.7%
788Students With Invalid Departments
Database
Easy
24
0.9%
789Queries on a Permutation With Key
Array, Binary Indexed Tree, Simulation
Medium
24
0.8%
790Pseudo-Palindromic Paths in a Binary Tree
Bit Manipulation, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
24
0.7%
791Reorder Routes to Make All Paths Lead to the City Zero
Depth-First Search, Breadth-First Search, Graph Theory
Medium
24
0.7%
792Longest Subarray of 1's After Deleting One Element
Array, Dynamic Programming, Sliding Window
Medium
24
0.7%
793Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree
Union-Find, Graph Theory, Sorting, Minimum Spanning Tree, Strongly Connected Component
Hard
24
0.7%
794Number of Subsequences That Satisfy the Given Sum Condition
Array, Two Pointers, Binary Search, Sorting
Medium
24
0.5%
795Clone N-ary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
24
0.8%
796Friendly Movies Streamed Last Month
Database
Easy
24
0.5%
797Minimum Numbers of Function Calls to Make Target Array
Array, Greedy, Bit Manipulation
Medium
24
0.6%
798Number of Sets of K Non-Overlapping Line Segments
Math, Dynamic Programming, Combinatorics, Prefix Sum
Medium
24
0.5%
799Build Binary Expression Tree From Infix Expression
String, Stack, Tree, Binary Tree
Hard
24
0.6%
800Maximum Nesting Depth of the Parentheses
String, Stack
Easy
24
0.8%
801Defuse the Bomb
Array, Sliding Window
Easy
24
0.8%
802Find the Missing IDs
Database
Medium
24
0.7%
803All Valid Triplets That Can Represent a Country
Database
Easy
24
0.8%
804Design Front Middle Back Queue
Array, Linked List, Design, Queue, Doubly-Linked List, Data Stream
Medium
24
0.6%
805Add Two Polynomials Represented as Linked Lists
Linked List, Math, Two Pointers
Medium
24
0.6%
806Invalid Tweets
Database
Easy
24
0.9%
807Count Ways to Make Array With Product
Array, Math, Dynamic Programming, Combinatorics, Number Theory
Hard
24
0.6%
808Number of Calls Between Two Persons
Database
Medium
24
0.8%
809Find Nearest Point That Has the Same X or Y Coordinate
Array
Easy
24
0.7%
810Count Pairs Of Nodes
Array, Hash Table, Two Pointers, Binary Search, Graph Theory, Sorting, Counting
Hard
24
0.4%
811Find Total Time Spent by Each Employee
Database
Easy
24
0.9%
812Sort Features by Popularity
Array, Hash Table, String, Sorting
Medium
24
0.7%
813Product's Price for Each Store
Database
Easy
24
0.8%
814Grand Slam Titles
Database
Medium
24
0.8%
815Maximize the Beauty of the Garden
Array, Hash Table, Greedy, Prefix Sum
Hard
24
0.7%
816Rearrange Products Table
Database
Easy
24
0.9%
817Ad-Free Sessions
Database
Easy
24
0.6%
818Find Interview Candidates
Database
Medium
24
0.6%
819Distinct Numbers in Each Subarray
Array, Hash Table, Sliding Window
Medium
24
0.8%
820Minimum Space Wasted From Packaging
Array, Binary Search, Sorting, Prefix Sum
Hard
24
0.3%
821Remove All Occurrences of a Substring
String, Stack, Simulation
Medium
24
0.8%
822Find a Peak Element II
Array, Binary Search, Matrix
Medium
24
0.6%
823Jump Game VIII
Array, Dynamic Programming, Stack, Graph Theory, Monotonic Stack, Shortest Path
Medium
24
0.5%
824Maximum of Minimum Values in All Subarrays
Array, Stack, Monotonic Stack
Medium
24
0.5%
825Count Number of Special Subsequences
Array, Dynamic Programming
Hard
24
0.5%
826Minimize the Difference Between Target and Chosen Elements
Array, Dynamic Programming, Matrix
Medium
24
0.4%
827Minimized Maximum of Products Distributed to Any Store
Array, Binary Search, Greedy
Medium
24
0.6%
828Sequentially Ordinal Rank Tracker
Design, Heap (Priority Queue), Data Stream, Ordered Set
Hard
24
0.6%
829Minimum Operations to Make the Array K-Increasing
Array, Binary Search
Hard
24
0.4%
830Maximum Twin Sum of a Linked List
Linked List, Two Pointers, Stack
Medium
24
0.8%
831Minimum Operations to Remove Adjacent Ones in Matrix
Array, Depth-First Search, Graph Theory, Matrix
Hard
24
0.4%
832Append K Integers With Minimal Sum
Array, Math, Greedy, Sorting
Medium
24
0.3%
833Longest Winning Streak
Database
Hard
24
0.5%
834Sum of Scores of Built Strings
String, Binary Search, Rolling Hash, Suffix Array, String Matching, Hash Function
Hard
24
0.5%
835Maximum Sum Score of Array
Array, Prefix Sum
Medium
24
0.6%
836Users With Two Purchases Within Seven Days
Database
Medium
24
0.5%
837Rearrange Characters to Make Target String
Hash Table, String, Counting
Easy
24
0.6%
838Number of Times a Driver Was a Passenger
Database
Medium
24
0.7%
839Products With Three or More Orders in Two Consecutive Years
Database
Medium
24
0.4%
840Product Sales Analysis V
Database
Easy
24
0.7%
841Time Needed to Rearrange a Binary String
String, Dynamic Programming, Simulation
Medium
24
0.5%
842Minimum Money Required Before Transactions
Array, Greedy, Sorting
Hard
24
0.4%
843Employees With Deductions
Database
Medium
24
0.4%
844Number of Distinct Averages
Array, Hash Table, Two Pointers, Sorting
Easy
24
0.6%
845Merge Operations to Turn Array Into a Palindrome
Array, Two Pointers, Greedy
Medium
24
0.7%
846Find the Pivot Integer
Math, Prefix Sum
Easy
24
0.8%
847Longest Square Streak in an Array
Array, Hash Table, Binary Search, Dynamic Programming, Sorting
Medium
24
0.5%
848Find Xor-Beauty of Array
Array, Math, Bit Manipulation
Medium
24
0.7%
849Count the Number of K-Big Indices
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
24
0.5%
850Find the Substring With Maximum Cost
Array, Hash Table, String, Dynamic Programming
Medium
24
0.6%
851Count the Number of K-Free Subsets
Array, Math, Dynamic Programming, Sorting, Combinatorics
Medium
24
0.5%
852Relocate Marbles
Array, Hash Table, Sorting, Simulation
Medium
24
0.5%
853Maximum Sum of Almost Unique Subarray
Array, Hash Table, Sliding Window
Medium
24
0.4%
854Number of Unique Categories
Union-Find, Interactive, Counting
Medium
24
0.8%
855Minimum Right Shifts to Sort the Array
Array
Easy
24
0.6%
856Maximal Range That Each Element Is Maximum in It
Array, Stack, Monotonic Stack
Medium
24
0.8%
857Subarrays Distinct Element Sum of Squares II
Array, Hash Table, Binary Indexed Tree, Segment Tree
Hard
24
0.2%
858Maximum Linear Stock Score
Array, Hash Table
Medium
24
0.6%
859Maximum Balanced Subsequence Sum
Array, Binary Search, Dynamic Programming, Binary Indexed Tree, Segment Tree
Hard
24
0.3%
860Distribute Candies Among Children I
Math, Combinatorics, Enumeration
Easy
24
0.8%
861Make Three Strings Equal
String
Easy
24
0.5%
862Count Beautiful Substrings II
Hash Table, Math, String, Number Theory, Prefix Sum
Hard
24
0.3%
863Distribute Candies Among Children III
Math, Combinatorics
Hard
24
0.6%
864Find the Maximum Number of Elements in Subset
Array, Hash Table, Enumeration
Medium
24
0.3%
865Count Numbers With Unique Digits II
Hash Table, Math, Dynamic Programming
Easy
24
0.9%
866Find the Number of Subarrays Where Boundary Elements Are Maximum
Array, Binary Search, Stack, Monotonic Stack
Hard
24
0.3%
867Count the Number of Special Characters II
Hash Table, String
Medium
24
0.6%
868Minimum Average of Smallest and Largest Elements
Array, Two Pointers, Sorting
Easy
24
0.9%
869Count Triplets with Even XOR Set Bits I
Array, Bit Manipulation
Easy
24
0.8%
870Count Triplets with Even XOR Set Bits II
Array, Bit Manipulation
Medium
24
0.6%
871Magic Squares In Grid
Array, Hash Table, Math, Matrix
Medium
24
0.6%
872Percentage of Users Attended a Contest
Database
Easy
24
0.6%
873Find the Length of the Longest Common Prefix
Array, Hash Table, String, Trie
Medium
24
0.6%
874Maximum Matrix Sum
Array, Greedy, Matrix
Medium
24
0.7%
875Two Best Non-Overlapping Events
Array, Binary Search, Dynamic Programming, Sorting, Heap (Priority Queue)
Medium
24
0.6%
876Max Chunks To Make Sorted
Array, Stack, Greedy, Sorting, Monotonic Stack
Medium
24
0.6%
877Count Servers that Communicate
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix, Counting
Medium
24
0.7%
878Shortest Matching Substring
Two Pointers, String, Binary Search, String Matching
Hard
24
0.2%
879Maximum Candies Allocated to K Children
Array, Binary Search
Medium
24
0.5%
880Minimum Stability Factor of Array
Array, Math, Binary Search, Greedy, Segment Tree, Number Theory
Hard
24
0.2%
881Trionic Array II
Array, Dynamic Programming
Hard
24
0.5%
882Maximum Capacity Within Budget
Array, Two Pointers, Binary Search, Sorting
Medium
24
0.2%
883Lexicographically Maximum MEX Array
Array, Hash Table, Greedy, Queue
Hard
24
0.6%
884Minimum Operations to Sort a Permutation
Array
Medium
24
0.3%
885Convert Sorted List to Binary Search Tree
Linked List, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
Medium
22
0.7%
886Binary Tree Preorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
22
0.8%
887Binary Tree Postorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
22
0.8%
888Excel Sheet Column Number
Math, String
Easy
22
0.7%
889Best Time to Buy and Sell Stock IV
Array, Dynamic Programming
Hard
22
0.5%
890Binary Tree Paths
String, Backtracking, Tree, Depth-First Search, Binary Tree
Easy
22
0.7%
891Single Number III
Array, Bit Manipulation
Medium
22
0.7%
892Encode and Decode Strings
Array, String, Design
Medium
22
0.5%
893Range Sum Query 2D - Immutable
Array, Design, Matrix, Prefix Sum
Medium
22
0.6%
894Minimum Number of Arrows to Burst Balloons
Array, Greedy, Sorting
Medium
22
0.6%
895Island Perimeter
Array, Depth-First Search, Breadth-First Search, Matrix
Easy
22
0.7%
896Base 7
Math, String
Easy
22
0.5%
897Longest Harmonious Subsequence
Array, Hash Table, Sliding Window, Sorting, Counting
Easy
22
0.6%
898Maximum Product of Three Numbers
Array, Math, Sorting
Easy
22
0.5%
899Course Schedule III
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
22
0.4%
900Guess the Word
Array, Math, String, Interactive, Game Theory
Hard
22
0.4%
901Transpose Matrix
Array, Matrix, Simulation
Easy
22
0.8%
902Find the Town Judge
Array, Hash Table, Graph Theory
Easy
22
0.5%
903Minimum Cost to Merge Stones
Array, Dynamic Programming, Prefix Sum
Hard
22
0.5%
904Pairs of Songs With Total Durations Divisible by 60
Array, Hash Table, Counting
Medium
22
0.5%
905Game Play Analysis IV
Database
Medium
22
0.4%
906Car Pooling
Array, Sorting, Heap (Priority Queue), Simulation, Prefix Sum
Medium
22
0.6%
907Queries Quality and Percentage
Database
Easy
22
0.5%
908Remove Sub-Folders from the Filesystem
Array, String, Depth-First Search, Trie
Medium
22
0.8%
909Find the Difference of Two Arrays
Array, Hash Table
Easy
22
0.8%
910Find Winner on a Tic Tac Toe Game
Array, Hash Table, Matrix, Simulation
Easy
22
0.5%
911Minimum Difficulty of a Job Schedule
Array, Dynamic Programming
Hard
22
0.6%
912Max Dot Product of Two Subsequences
Array, Dynamic Programming
Hard
22
0.7%
913Path With Minimum Effort
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Medium
22
0.6%
914Maximum Ice Cream Bars
Array, Greedy, Sorting, Counting Sort
Medium
22
0.8%
915Find the Prefix Common Array of Two Arrays
Array, Hash Table, Bit Manipulation
Medium
22
0.9%
916Return Length of Arguments PassedEasy
22
0.9%
917Count Elements With Maximum Frequency
Array, Hash Table, Counting
Easy
22
0.8%
918Find the Median of the Uniqueness Array
Array, Hash Table, Binary Search, Sliding Window
Hard
22
0.3%
919Minimum Fuel Cost to Report to the Capital
Tree, Depth-First Search, Breadth-First Search, Graph Theory
Medium
22
0.7%
920Delete Nodes From Linked List Present in Array
Array, Hash Table, Linked List
Medium
22
0.7%
921Count Vowel Strings in Ranges
Array, String, Prefix Sum
Medium
22
0.7%
922Number of Zero-Filled Subarrays
Array, Math
Medium
22
0.7%
923Course Schedule IV
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
22
0.6%
924Final Prices With a Special Discount in a Shop
Array, Stack, Monotonic Stack
Easy
22
0.8%
925House Robber IV
Array, Binary Search, Dynamic Programming, Greedy
Medium
22
0.6%
926Minimum Distance to the Target Element
Array
Easy
22
0.6%
927Minimum Time to Activate String
Array, Binary Search
Medium
22
0.5%
928Maximum Median Sum of Subsequences of Size 3
Array, Math, Greedy, Sorting, Game Theory
Medium
22
0.7%
929Avoid Flood in The City
Array, Hash Table, Binary Search, Greedy, Heap (Priority Queue)
Medium
22
0.4%
930Minimum Number of Groups to Create a Valid Assignment
Array, Hash Table, Greedy
Medium
22
0.3%
931Minimize Array Sum Using Divisible Replacements
Array, Hash Table, Math, Greedy, Number Theory
Medium
22
0.3%
932Minimum Flips to Make Binary String Coherent
String
Medium
22
0.2%
933Scramble String
String, Dynamic Programming
Hard
20
0.4%
934Minimum Depth of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
20
0.5%
935Populating Next Right Pointers in Each Node II
Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
20
0.6%
936Factorial Trailing Zeroes
Math
Medium
20
0.5%
937Trips and Users
Database
Hard
20
0.4%
938Ugly Number II
Hash Table, Math, Dynamic Programming, Heap (Priority Queue)
Medium
20
0.5%
939Minimum Height Trees
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
20
0.4%
940Count of Smaller Numbers After Self
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
20
0.4%
941Intersection of Two Arrays II
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
20
0.6%
942Valid Perfect Square
Math, Binary Search
Easy
20
0.5%
943Elimination Game
Math, Recursion
Medium
20
0.5%
944Add Two Numbers II
Linked List, Math, Stack
Medium
20
0.6%
945Sum of Square Numbers
Math, Two Pointers, Binary Search
Medium
20
0.4%
946Find Duplicate Subtrees
Hash Table, Tree, Depth-First Search, Binary Tree
Medium
20
0.6%
947Search in a Binary Search Tree
Tree, Binary Search Tree, Binary Tree
Easy
20
0.8%
948Basic Calculator III
Math, String, Stack, Recursion
Hard
20
0.5%
949Nth Magical Number
Math, Binary Search
Hard
20
0.4%
950Valid Mountain Array
Array
Easy
20
0.4%
951Find Common Characters
Array, Hash Table, String
Easy
20
0.7%
952Minimum Cost to Connect Sticks
Array, Greedy, Heap (Priority Queue)
Medium
20
0.7%
953N-th Tribonacci Number
Math, Dynamic Programming, Memoization
Easy
20
0.6%
954Longest Happy String
String, Greedy, Heap (Priority Queue)
Medium
20
0.7%
955Number of Visible People in a Queue
Array, Stack, Monotonic Stack
Hard
20
0.7%
956Minimum Remove to Make Valid Parentheses
String, Stack
Medium
20
0.7%
957Find N Unique Integers Sum up to Zero
Array, Math
Easy
20
0.8%
958Longest Happy Prefix
String, Rolling Hash, String Matching, Hash Function
Hard
20
0.5%
959Number of Good Pairs
Array, Hash Table, Math, Counting
Easy
20
0.9%
960Sort Array by Increasing Frequency
Array, Hash Table, Sorting
Easy
20
0.8%
961Nearest Exit from Entrance in Maze
Array, Breadth-First Search, Matrix
Medium
20
0.5%
962Number of Ways to Arrive at Destination
Dynamic Programming, Graph Theory, Topological Sort, Shortest Path
Medium
20
0.4%
963Minimum Number of Swaps to Make the String Balanced
Two Pointers, String, Stack, Greedy
Medium
20
0.8%
964Minimum Difference Between Highest and Lowest of K Scores
Array, Sliding Window, Sorting
Easy
20
0.7%
965Create Binary Tree From Descriptions
Array, Hash Table, Tree, Binary Tree
Medium
20
0.8%
966Successful Pairs of Spells and Potions
Array, Two Pointers, Binary Search, Sorting
Medium
20
0.5%
967Count Number of Bad Pairs
Array, Hash Table, Math, Counting
Medium
20
0.5%
968CounterEasy
20
0.8%
969Filter Elements from ArrayEasy
20
0.9%
970Find the Maximum Achievable Number
Math
Easy
20
0.9%
971Parallel Courses III
Array, Dynamic Programming, Graph Theory, Topological Sort
Hard
20
0.7%
972Clear Digits
String, Stack, Simulation
Easy
20
0.8%
973Separate Squares I
Array, Binary Search
Medium
20
0.6%
974Lexicographically Minimum String After Removing Stars
Hash Table, String, Stack, Greedy, Heap (Priority Queue)
Medium
20
0.5%
975Greatest Sum Divisible by Three
Array, Dynamic Programming, Greedy, Sorting
Medium
20
0.6%
976Count Subarrays of Length Three With a Condition
Array
Easy
20
0.6%
977Count the Number of Substrings With Dominant Ones
String, Enumeration
Medium
20
0.4%
978Find the K-th Character in String Game I
Math, Bit Manipulation, Recursion, Simulation
Easy
20
0.8%
979Find the Maximum Length of Valid Subsequence I
Array, Dynamic Programming
Medium
20
0.5%
980Soup Servings
Math, Dynamic Programming, Probability and Statistics
Medium
20
0.6%
981Threshold Majority Queries
Array, Hash Table, Binary Search, Divide and Conquer, Counting, Prefix Sum
Hard
20
0.2%
982New 21 Game
Math, Dynamic Programming, Sliding Window, Probability and Statistics
Medium
20
0.5%
983Find the Minimum Area to Cover All Ones II
Array, Matrix, Enumeration
Hard
20
0.6%
984Minimum Sensors to Cover Grid
Math
Medium
20
0.7%
985Maximum Calories Burnt from Jumps
Array, Two Pointers, Greedy, Sorting
Medium
20
0.7%
986Maximize Points After Choosing K Tasks
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
20
0.6%
987Total Sum of Interaction Cost in Tree Groups
Array, Tree, Depth-First Search
Hard
20
0.5%
988Maximum Score After Binary Swaps
Array, String, Greedy, Heap (Priority Queue)
Medium
20
0.4%
989Reverse String Prefix
Two Pointers, String
Easy
20
0.9%
990Minimum Cost to Partition a Binary String
String, Divide and Conquer, Prefix Sum
Hard
20
0.5%
991Sum of GCD of Formed Pairs
Array, Math, Two Pointers, Sorting, Simulation, Number Theory
Medium
20
0.7%
992Maximum Total Value of Covered Indices
Array, String, Dynamic Programming, Greedy
Medium
20
0.3%
993Valid Phone Numbers
Shell
Easy
18
0.3%
994Longest Substring with At Most K Distinct Characters
Hash Table, String, Sliding Window
Medium
18
0.5%
995Power of Four
Math, Bit Manipulation, Recursion
Easy
18
0.5%
996Sum of Left Leaves
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
18
0.6%
997Sliding Window Median
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
18
0.4%
998Perfect Number
Math
Easy
18
0.5%
999Find Largest Value in Each Tree Row
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
18
0.7%
1000Minimum Time Difference
Array, Math, String, Sorting
Medium
18
0.6%
1001Find the Closest Palindrome
Math, String
Hard
18
0.3%
1002Human Traffic of Stadium
Database
Hard
18
0.5%
1003Trim a Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
18
0.7%
1004Number of Atoms
Hash Table, String, Stack, Sorting
Hard
18
0.7%
1005Maximize Distance to Closest Person
Array
Medium
18
0.5%
1006Reordered Power of 2
Hash Table, Math, Sorting, Counting, Enumeration
Medium
18
0.7%
1007Walking Robot Simulation
Array, Hash Table, Simulation
Medium
18
0.6%
1008Next Greater Node In Linked List
Array, Linked List, Stack, Monotonic Stack
Medium
18
0.6%
1009Robot Bounded In Circle
Math, String, Simulation
Medium
18
0.6%
1010Grumpy Bookstore Owner
Array, Sliding Window
Medium
18
0.6%
1011Minimum Knight Moves
Breadth-First Search
Medium
18
0.4%
1012Count Number of Nice Subarrays
Array, Hash Table, Math, Sliding Window, Prefix Sum
Medium
18
0.8%
1013Find Numbers with Even Number of Digits
Array, Math
Easy
18
0.8%
1014Check If N and Its Double Exist
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
18
0.4%
1015Movie Rating
Database
Medium
18
0.4%
1016Count Good Nodes in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
18
0.7%
1017Minimum Difference Between Largest and Smallest Value in Three Moves
Array, Greedy, Sorting
Medium
18
0.6%
1018Matrix Diagonal Sum
Array, Matrix
Easy
18
0.8%
1019Sum of Absolute Differences in a Sorted Array
Array, Math, Prefix Sum
Medium
18
0.7%
1020Maximum Number of Events That Can Be Attended II
Array, Binary Search, Dynamic Programming, Sorting
Hard
18
0.6%
1021Minimum Limit of Balls in a Bag
Array, Binary Search
Medium
18
0.7%
1022Buildings With an Ocean View
Array, Stack, Monotonic Stack
Medium
18
0.8%
1023Find the Winner of the Circular Game
Array, Math, Recursion, Queue, Simulation
Medium
18
0.8%
1024Detonate the Maximum Bombs
Array, Math, Depth-First Search, Breadth-First Search, Graph Theory, Geometry
Medium
18
0.5%
1025Delete the Middle Node of a Linked List
Linked List, Two Pointers
Medium
18
0.6%
1026Check if a Parentheses String Can Be Valid
String, Stack, Greedy
Medium
18
0.5%
1027Longest Nice Subarray
Array, Bit Manipulation, Sliding Window
Medium
18
0.6%
1028Smallest Even Multiple
Math, Number Theory
Easy
18
0.9%
1029Continuous Subarrays
Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Medium
18
0.6%
1030Score of a String
String
Easy
18
0.9%
1031Nth Digit
Math, Binary Search
Medium
18
0.4%
1032Minimum Cost to Convert String II
Array, String, Dynamic Programming, Graph Theory, Trie, Shortest Path
Hard
18
0.6%
1033Finding 3-Digit Even Numbers
Array, Hash Table, Recursion, Sorting, Enumeration
Easy
18
0.8%
1034Longest Subarray With Maximum Bitwise AND
Array, Bit Manipulation, Brainteaser
Medium
18
0.7%
1035Lexicographically Smallest String After Applying Operations
String, Depth-First Search, Breadth-First Search, Enumeration
Medium
18
0.8%
1036String Compression III
String
Medium
18
0.7%
1037Last Stone Weight II
Array, Dynamic Programming
Medium
18
0.6%
1038Separate Black and White Balls
Two Pointers, String, Greedy
Medium
18
0.6%
1039K-th Smallest in Lexicographical Order
Trie
Hard
18
0.5%
1040Most Beautiful Item for Each Query
Array, Binary Search, Sorting
Medium
18
0.6%
1041Jump Game VII
String, Dynamic Programming, Sliding Window, Prefix Sum
Medium
18
0.4%
1042Largest 1-Bordered Square
Array, Dynamic Programming, Matrix
Medium
18
0.5%
1043Maximum Sum of 3 Non-Overlapping Subarrays
Array, Dynamic Programming, Sliding Window, Prefix Sum
Hard
18
0.6%
1044Special Binary String
String, Divide and Conquer, Sorting
Hard
18
0.8%
1045Nim Game
Math, Brainteaser, Game Theory
Easy
18
0.6%
1046Word Subsets
Array, Hash Table, String
Medium
18
0.6%
1047Maximum Performance of a Team
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
18
0.5%
1048Even Odd Tree
Tree, Breadth-First Search, Binary Tree
Medium
18
0.7%
1049Maximum Absolute Sum of Any Subarray
Array, Dynamic Programming
Medium
18
0.7%
1050Robot Return to Origin
String, Simulation
Easy
18
0.8%
1051Insertion Sort List
Linked List, Sorting
Medium
18
0.6%
1052Detect Cycles in 2D Grid
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
18
0.6%
1053Possible Bipartition
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
18
0.5%
1054Unique 3-Digit Even Numbers
Array, Hash Table, Recursion, Enumeration
Easy
18
0.7%
1055Maximum Number of Tasks You Can Assign
Array, Two Pointers, Binary Search, Greedy, Queue, Sorting, Monotonic Queue
Hard
18
0.5%
1056Minimum Equal Sum of Two Arrays After Replacing Zeros
Array, Greedy
Medium
18
0.5%
1057Total Characters in String After Transformations I
Hash Table, Math, String, Dynamic Programming, Counting
Medium
18
0.5%
1058Lexicographically Smallest Equivalent String
String, Union-Find
Medium
18
0.8%
1059Find All K-Distant Indices in an Array
Array, Two Pointers
Easy
18
0.8%
1060Kth Smallest Product of Two Sorted Arrays
Array, Binary Search
Hard
18
0.5%
1061Minimum Cost to Reach Destination in Time
Array, Dynamic Programming, Graph Theory
Hard
18
0.4%
1062Reschedule Meetings for Maximum Free Time I
Array, Greedy, Sliding Window
Medium
18
0.5%
1063Fix Names in a Table
Database
Easy
18
0.6%
1064Maximize Subarrays After Removing One Conflicting Pair
Array, Segment Tree, Enumeration, Prefix Sum
Hard
18
0.6%
1065Fruits Into Baskets II
Array, Binary Search, Segment Tree, Simulation, Ordered Set
Easy
18
0.7%
1066Rotating the Box
Array, Two Pointers, Matrix
Medium
18
0.8%
1067Vowel Spellchecker
Array, Hash Table, String
Medium
18
0.6%
1068Lexicographically Smallest Permutation Greater Than Target
Hash Table, String, Greedy, Counting, Enumeration
Medium
18
0.3%
1069Transformed Array
Array, Simulation
Easy
18
0.7%
1070Longest Balanced Substring I
Hash Table, String, Counting, Enumeration
Medium
18
0.7%
1071Champagne Tower
Dynamic Programming
Medium
18
0.6%
1072Total Waviness of Numbers in Range I
Math, Dynamic Programming, Enumeration
Medium
18
0.9%
1073Remove Duplicates from Sorted List II
Linked List, Two Pointers
Medium
16
0.5%
1074Binary Tree Level Order Traversal II
Tree, Breadth-First Search, Binary Tree
Medium
16
0.7%
1075Bitwise AND of Numbers Range
Bit Manipulation
Medium
16
0.5%
1076Contains Duplicate III
Array, Sliding Window, Sorting, Bucket Sort, Ordered Set
Hard
16
0.2%
1077Count Complete Tree Nodes
Binary Search, Bit Manipulation, Tree, Binary Tree
Easy
16
0.7%
1078Shortest Word Distance
Array, String
Easy
16
0.7%
1079Remove Invalid Parentheses
String, Backtracking, Breadth-First Search
Hard
16
0.5%
1080Best Time to Buy and Sell Stock with Cooldown
Array, Dynamic Programming
Medium
16
0.6%
1081Shortest Distance from All Buildings
Array, Breadth-First Search, Matrix
Hard
16
0.4%
1082Count of Range Sum
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
16
0.4%
1083Combination Sum IV
Array, Dynamic Programming
Medium
16
0.6%
1084Arithmetic Slices
Array, Dynamic Programming, Sliding Window
Medium
16
0.6%
1085Can I Win
Math, Dynamic Programming, Bit Manipulation, Memoization, Game Theory, Bitmask
Medium
16
0.3%
1086Optimal Account Balancing
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Hard
16
0.5%
1087Relative Ranks
Array, Sorting, Heap (Priority Queue)
Easy
16
0.7%
1088Shortest Unsorted Continuous Subarray
Array, Two Pointers, Stack, Greedy, Sorting, Monotonic Stack
Medium
16
0.4%
1089Investments in 2016
Database
Medium
16
0.5%
1090Not Boring Movies
Database
Easy
16
0.8%
1091Best Time to Buy and Sell Stock with Transaction Fee
Array, Dynamic Programming, Greedy
Medium
16
0.7%
1092Maximum Length of Repeated Subarray
Array, Binary Search, Dynamic Programming, Sliding Window, Rolling Hash, Hash Function
Medium
16
0.5%
1093Find Smallest Letter Greater Than Target
Array, Binary Search
Easy
16
0.6%
1094K-th Symbol in Grammar
Math, Bit Manipulation, Recursion
Medium
16
0.5%
1095Rabbits in Forest
Array, Hash Table, Math, Greedy
Medium
16
0.6%
1096Hand of Straights
Array, Hash Table, Greedy, Sorting
Medium
16
0.6%
1097Minimum Cost to Hire K Workers
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
16
0.6%
1098Monotonic Array
Array
Easy
16
0.6%
1099Sort Array By Parity
Array, Two Pointers, Sorting
Easy
16
0.8%
1100Range Sum of BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
16
0.9%
1101Reveal Cards In Increasing Order
Array, Queue, Sorting, Simulation
Medium
16
0.8%
1102Regions Cut By Slashes
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
16
0.8%
1103Divisor Game
Math, Dynamic Programming, Brainteaser, Game Theory
Easy
16
0.7%
1104Maximum Level Sum of a Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
16
0.7%
1105As Far from Land as Possible
Array, Dynamic Programming, Breadth-First Search, Matrix
Medium
16
0.5%
1106Partition Array for Maximum Sum
Array, Dynamic Programming
Medium
16
0.8%
1107Filling Bookcase Shelves
Array, Dynamic Programming
Medium
16
0.7%
1108Defanging an IP Address
String
Easy
16
0.9%
1109Stone Game II
Array, Math, Dynamic Programming, Prefix Sum, Game Theory
Medium
16
0.7%
1110Invalid Transactions
Array, Hash Table, String, Sorting
Medium
16
0.3%
1111Find Resultant Array After Removing Anagrams
Array, Hash Table, String, Sorting
Easy
16
0.7%
1112Minimum Insertion Steps to Make a String Palindrome
String, Dynamic Programming
Hard
16
0.7%
1113Jump Game IV
Array, Hash Table, Breadth-First Search
Hard
16
0.5%
1114Find the City With the Smallest Number of Neighbors at a Threshold Distance
Dynamic Programming, Graph Theory, Shortest Path
Medium
16
0.7%
1115Maximum Product of Splitted Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
16
0.6%
1116Design a Stack With Increment Operation
Array, Stack, Design
Medium
16
0.8%
1117Cherry Pickup II
Array, Dynamic Programming, Matrix
Hard
16
0.7%
1118Maximum Product of Two Elements in an Array
Array, Sorting, Heap (Priority Queue)
Easy
16
0.8%
1119Minimum Number of Increments on Subarrays to Form a Target Array
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Hard
16
0.8%
1120Find Kth Bit in Nth Binary String
String, Recursion, Simulation
Medium
16
0.7%
1121Minimum Number of Operations to Move All Balls to Each Box
Array, String, Prefix Sum
Medium
16
0.9%
1122Maximum Population Year
Array, Counting, Prefix Sum
Easy
16
0.6%
1123Final Value of Variable After Performing Operations
Array, String, Simulation
Easy
16
0.9%
1124Step-By-Step Directions From a Binary Tree Node to Another
String, Tree, Depth-First Search, Binary Tree
Medium
16
0.6%
1125Root Equals Sum of Children
Tree, Binary Tree
Easy
16
0.9%
1126Number of Unique Subjects Taught by Each Teacher
Database
Easy
16
0.9%
1127Apply Operations to an Array
Array, Two Pointers, Simulation
Easy
16
0.7%
1128Minimize the Maximum Difference of Pairs
Array, Binary Search, Dynamic Programming, Greedy, Sorting
Medium
16
0.5%
1129Sort the Jumbled Numbers
Array, Sorting
Medium
16
0.6%
1130Primary Department for Each Employee
Database
Easy
16
0.7%
1131Minimum Cost to Convert String I
Array, String, Graph Theory, Shortest Path
Medium
16
0.6%
1132Count the Number of Complete Components
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
16
0.8%
1133Water and Jug Problem
Math, Depth-First Search, Breadth-First Search
Medium
16
0.5%
1134Minimum Operations to Make Binary Array Elements Equal to One I
Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum
Medium
16
0.8%
1135Add to Array-Form of Integer
Array, Math
Easy
16
0.5%
1136Valid Tic-Tac-Toe State
Array, Matrix
Medium
16
0.3%
1137Sum of Prefix Scores of Strings
Array, String, Trie, Counting
Hard
16
0.6%
1138Count Number of Maximum Bitwise-OR Subsets
Array, Backtracking, Bit Manipulation, Enumeration
Medium
16
0.9%
1139Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold
Array, Sliding Window
Medium
16
0.7%
1140Sum of Unique Elements
Array, Hash Table, Counting
Easy
16
0.8%
1141Make Lexicographically Smallest Array by Swapping Elements
Array, Union-Find, Sorting
Medium
16
0.6%
1142Maximum Subarray Min-Product
Array, Stack, Monotonic Stack, Prefix Sum
Medium
16
0.4%
1143Maximum Tastiness of Candy Basket
Array, Binary Search, Greedy, Sorting
Medium
16
0.7%
1144Delete Columns to Make Sorted
Array, String
Easy
16
0.8%
1145Design Snake Game
Array, Hash Table, Design, Queue, Simulation
Medium
16
0.4%
1146The k-th Lexicographical String of All Happy Strings of Length n
String, Backtracking
Medium
16
0.9%
1147Number of Sub-arrays With Odd Sum
Array, Math, Dynamic Programming, Prefix Sum
Medium
16
0.6%
1148Separate Squares II
Array, Binary Search, Segment Tree, Sweep Line
Hard
16
0.6%
1149Length of Longest Fibonacci Subsequence
Array, Hash Table, Dynamic Programming
Medium
16
0.6%
1150Minimum Domino Rotations For Equal Row
Array, Greedy
Medium
16
0.6%
1151Zero Array Transformation I
Array, Prefix Sum
Medium
16
0.5%
1152Maximum Difference Between Even and Odd Frequency I
Hash Table, String, Counting
Easy
16
0.6%
1153Maximum Difference Between Increasing Elements
Array
Easy
16
0.7%
1154Maximum Balanced Shipments
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Medium
16
0.6%
1155Range Product Queries of Powers
Array, Bit Manipulation, Prefix Sum
Medium
16
0.6%
1156Ways to Express an Integer as Sum of Powers
Dynamic Programming
Medium
16
0.5%
1157Find the Minimum Area to Cover All Ones I
Array, Matrix
Medium
16
0.8%
1158Design Task Manager
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
16
0.5%
1159Find Target Indices After Sorting Array
Array, Binary Search, Sorting
Easy
16
0.8%
1160Maximum Total Damage With Spell Casting
Array, Hash Table, Two Pointers, Binary Search, Dynamic Programming, Sorting, Counting
Medium
16
0.5%
1161Set Intersection Size At Least Two
Array, Greedy, Sorting
Hard
16
0.6%
1162Maximum Subarray Sum With Length Divisible by K
Array, Hash Table, Prefix Sum
Medium
16
0.5%
1163Minimum Penalty for a Shop
String, Prefix Sum
Medium
16
0.7%
1164Minimum Pair Removal to Sort Array II
Array, Hash Table, Linked List, Heap (Priority Queue), Simulation, Doubly-Linked List, Ordered Set
Hard
16
0.4%
1165Minimum Cost Path with Edge Reversals
Graph Theory, Heap (Priority Queue), Shortest Path
Medium
16
0.6%
1166Minimum Initial Energy to Finish Tasks
Array, Greedy, Sorting
Hard
16
0.8%
1167Minimum Moves to Make Array Complementary
Array, Hash Table, Prefix Sum
Medium
16
0.6%
1168Minimum Cost of Buying Candies With Discount
Array, Greedy, Sorting
Easy
16
0.7%
1169Earliest Finish Time for Land and Water Rides I
Array, Two Pointers, Binary Search, Greedy, Sorting
Easy
16
0.7%
1170Earliest Finish Time for Land and Water Rides II
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
16
0.6%
1171Process String with Special Operations II
String, Simulation
Hard
16
0.4%
1172Number of ZigZag Arrays I
Dynamic Programming, Prefix Sum
Hard
16
0.5%
1173Maximum Gap
Array, Sorting, Bucket Sort, Radix Sort
Medium
13
0.5%
1174Fraction to Recurring Decimal
Hash Table, Math, String
Medium
13
0.3%
1175Create Maximum Number
Array, Two Pointers, Stack, Greedy, Monotonic Stack
Hard
13
0.4%
1176Wiggle Sort II
Array, Divide and Conquer, Greedy, Sorting, Quickselect
Medium
13
0.4%
1177Guess Number Higher or Lower
Binary Search, Interactive
Easy
13
0.6%
1178Strong Password Checker
String, Greedy, Heap (Priority Queue)
Hard
13
0.2%
1179Minimum Moves to Equal Array Elements
Array, Math
Medium
13
0.6%
1180Kill Process
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
13
0.7%
1181Friend Requests II: Who Has the Most Friends
Database
Medium
13
0.6%
1182Dota2 Senate
String, Greedy, Queue
Medium
13
0.5%
1183Reach a Number
Math, Binary Search
Medium
13
0.5%
1184Employee Free Time
Array, Sweep Line, Sorting, Heap (Priority Queue)
Hard
13
0.7%
1185Construct Quad Tree
Array, Divide and Conquer, Tree, Matrix
Medium
13
0.8%
1186Number of Matching Subsequences
Array, Hash Table, String, Binary Search, Dynamic Programming, Trie, Sorting
Medium
13
0.5%
1187Profitable Schemes
Array, Dynamic Programming
Hard
13
0.5%
1188Fair Candy Swap
Array, Hash Table, Binary Search, Sorting
Easy
13
0.7%
1189All Possible Full Binary Trees
Dynamic Programming, Tree, Recursion, Memoization, Binary Tree
Medium
13
0.8%
1190Minimum Increment to Make Array Unique
Array, Greedy, Sorting, Counting
Medium
13
0.6%
1191Validate Stack Sequences
Array, Stack, Simulation
Medium
13
0.7%
1192Verifying an Alien Dictionary
Array, Hash Table, String
Easy
13
0.6%
1193Cousins in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
13
0.6%
1194Project Employees I
Database
Easy
13
0.7%
1195Game Play Analysis I
Database
Easy
13
0.8%
1196Relative Sort Array
Array, Hash Table, Sorting, Counting Sort
Easy
13
0.8%
1197Last Person to Fit in the Bus
Database
Medium
13
0.7%
1198Maximum Side Length of a Square with Sum Less than or Equal to Threshold
Array, Binary Search, Matrix, Prefix Sum
Medium
13
0.7%
1199Number of Steps to Reduce a Number to Zero
Math, Bit Manipulation
Easy
13
0.9%
1200Maximum Score After Splitting a String
String, Prefix Sum
Easy
13
0.7%
1201Water Bottles
Math, Simulation
Easy
13
0.7%
1202Maximum Length of Subarray With Positive Product
Array, Dynamic Programming, Greedy
Medium
13
0.4%
1203Richest Customer Wealth
Array, Matrix
Easy
13
0.9%
1204Partitioning Into Minimum Number Of Deci-Binary Numbers
String, Greedy
Medium
13
0.9%
1205Check if the Sentence Is Pangram
Hash Table, String
Easy
13
0.8%
1206Reverse Prefix of Word
Two Pointers, String, Stack
Easy
13
0.9%
1207Find the Minimum and Maximum Number of Nodes Between Critical Points
Linked List
Medium
13
0.7%
1208Find Subsequence of Length K With the Largest Sum
Array, Hash Table, Sorting, Heap (Priority Queue)
Easy
13
0.6%
1209Solving Questions With Brainpower
Array, Dynamic Programming
Medium
13
0.6%
1210Array Prototype LastEasy
13
0.7%
1211Extra Characters in a String
Array, Hash Table, String, Dynamic Programming, Trie
Medium
13
0.6%
1212Counter IIEasy
13
0.8%
1213Count Complete Subarrays in an Array
Array, Hash Table, Sliding Window
Medium
13
0.8%
1214Count Pairs Whose Sum is Less than Target
Array, Two Pointers, Binary Search, Sorting
Easy
13
0.9%
1215Divide Array Into Arrays With Max Difference
Array, Greedy, Sorting
Medium
13
0.8%
1216Find the Maximum Length of Valid Subsequence II
Array, Dynamic Programming
Medium
13
0.6%
1217Minimum Deletions to Make String Balanced
String, Dynamic Programming, Stack
Medium
13
0.7%
1218Task Scheduler II
Array, Hash Table, Simulation
Medium
13
0.5%
1219Split a String in Balanced Strings
String, Greedy, Counting
Easy
13
0.9%
1220Valid Word
String
Easy
13
0.5%
1221Minimum Index Sum of Two Lists
Array, Hash Table, String
Easy
13
0.6%
1222Length of the Longest Subsequence That Sums to Target
Array, Dynamic Programming
Medium
13
0.4%
1223N-ary Tree Postorder Traversal
Stack, Tree, Depth-First Search
Easy
13
0.8%
1224Out of Boundary Paths
Dynamic Programming
Medium
13
0.5%
1225Longest Continuous Increasing Subsequence
Array
Easy
13
0.5%
1226Find the Longest Substring Containing Vowels in Even Counts
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
13
0.8%
1227Rank Transform of an Array
Array, Hash Table, Sorting
Easy
13
0.7%
1228Biggest Single Number
Database
Easy
13
0.7%
1229Divide Players Into Teams of Equal Skill
Array, Hash Table, Two Pointers, Sorting
Medium
13
0.7%
1230Rearrange String k Distance Apart
Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
Hard
13
0.4%
1231Minimum Subsequence in Non-Increasing Order
Array, Greedy, Sorting
Easy
13
0.7%
1232Check if Number is a Sum of Powers of Three
Math
Medium
13
0.8%
1233Adjacent Increasing Subarrays Detection I
Array
Easy
13
0.5%
1234Take K of Each Character From Left and Right
Hash Table, String, Sliding Window
Medium
13
0.5%
1235The Most Frequently Ordered Products for Each Customer
Database
Medium
13
0.8%
1236Find Score of an Array After Marking All Elements
Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
Medium
13
0.6%
1237Best Sightseeing Pair
Array, Dynamic Programming
Medium
13
0.6%
1238Shifting Letters II
Array, String, Prefix Sum
Medium
13
0.5%
1239Find Users With Valid E-Mails
Database
Easy
13
0.4%
1240Minimize XOR
Greedy, Bit Manipulation
Medium
13
0.6%
1241Neighboring Bitwise XOR
Array, Bit Manipulation
Medium
13
0.8%
1242Tree Diameter
Tree, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
13
0.6%
1243Map of Highest Peak
Array, Breadth-First Search, Matrix
Medium
13
0.8%
1244Number of Subarrays with Bounded Maximum
Array, Two Pointers
Medium
13
0.6%
1245Maximum Good Subarray Sum
Array, Hash Table, Prefix Sum
Medium
13
0.2%
1246Find the Punishment Number of an Integer
Math, Backtracking
Medium
13
0.8%
1247Self Dividing Numbers
Math
Easy
13
0.8%
1248Maximum Sum of Two Non-Overlapping Subarrays
Array, Dynamic Programming, Sliding Window
Medium
13
0.6%
1249Count Total Number of Colored Cells
Math
Medium
13
0.7%
1250Find Duplicate File in System
Array, Hash Table, String
Medium
13
0.7%
1251Zero Array Transformation II
Array, Two Pointers, Binary Search, Prefix Sum
Medium
13
0.4%
1252Minimum Time to Repair Cars
Array, Binary Search
Medium
13
0.6%
1253Count Vowel Substrings of a String
Hash Table, String
Easy
13
0.7%
1254Number of Pairs Satisfying Inequality
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
13
0.5%
1255Find Closest Node to Given Two Nodes
Depth-First Search, Graph Theory
Medium
13
0.5%
1256Max Difference You Can Get From Changing an Integer
Math, Greedy
Medium
13
0.5%
1257Minimum Time to Complete Trips
Array, Binary Search
Medium
13
0.4%
1258Find the Original Typed String I
String
Easy
13
0.7%
1259Find the Original Typed String II
String, Dynamic Programming, Prefix Sum
Hard
13
0.5%
1260Last Day Where You Can Still Cross
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Hard
13
0.7%
1261Minimum Pair Removal to Sort Array I
Array, Hash Table, Linked List, Heap (Priority Queue), Simulation, Doubly-Linked List, Ordered Set
Easy
13
0.7%
1262Count Hills and Valleys in an Array
Array
Easy
13
0.7%
1263Fruits Into Baskets III
Array, Binary Search, Segment Tree, Ordered Set
Medium
13
0.4%
1264Count Submatrices With All Ones
Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
Medium
13
0.7%
1265Find the Number of Ways to Place People I
Array, Math, Geometry, Sorting, Enumeration
Medium
13
0.6%
1266Minimum Operations to Make the Integer Zero
Bit Manipulation, Brainteaser, Enumeration
Medium
13
0.6%
1267Convert Integer to the Sum of Two No-Zero Integers
Math
Easy
13
0.6%
1268Number of People Aware of a Secret
Dynamic Programming, Queue, Simulation
Medium
13
0.6%
1269Maximum Number of Words Found in Sentences
Array, String
Easy
13
0.9%
1270Taking Maximum Energy From the Mystic Dungeon
Array, Dynamic Programming, Prefix Sum
Medium
13
0.6%
1271Smallest Missing Non-negative Integer After Operations
Array, Hash Table, Math, Greedy
Medium
13
0.6%
1272Best Time to Buy and Sell Stock V
Array, Dynamic Programming
Medium
13
0.6%
1273Pyramid Transition Matrix
Hash Table, String, Backtracking, Bit Manipulation
Medium
13
0.6%
1274N-Repeated Element in Size 2N Array
Array, Hash Table
Easy
13
0.8%
1275Maximize Area of Square Hole in Grid
Array, Sorting
Medium
13
0.6%
1276Construct the Minimum Bitwise Array II
Array, Bit Manipulation
Medium
13
0.7%
1277Longest Balanced Subarray I
Array, Hash Table, Divide and Conquer, Segment Tree, Prefix Sum
Medium
13
0.7%
1278Longest Balanced Substring II
Hash Table, String, Prefix Sum
Medium
13
0.4%
1279Check If a String Contains All Binary Codes of Size K
Hash Table, String, Bit Manipulation, Rolling Hash, Hash Function
Medium
13
0.6%
1280Buddy Strings
Hash Table, String
Easy
13
0.3%
1281Find Minimum in Rotated Sorted Array II
Array, Binary Search
Hard
10
0.5%
1282Best Meeting Point
Array, Math, Sorting, Matrix
Hard
10
0.6%
1283Palindrome Pairs
Array, Hash Table, String, Trie, Hash Function
Hard
10
0.4%
1284Integer Break
Math, Dynamic Programming
Medium
10
0.6%
1285Find Leaves of Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
10
0.8%
1286Super Pow
Math, Divide and Conquer
Medium
10
0.4%
1287Queue Reconstruction by Height
Array, Binary Indexed Tree, Segment Tree, Sorting
Medium
10
0.7%
1288Find Right Interval
Array, Binary Search, Sorting
Medium
10
0.6%
1289Arithmetic Slices II - Subsequence
Array, Dynamic Programming
Hard
10
0.6%
12904Sum II
Array, Hash Table
Medium
10
0.6%
1291Find Bottom Left Tree Value
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
10
0.7%
1292Brick Wall
Array, Hash Table
Medium
10
0.6%
1293Delete Operation for Two Strings
String, Dynamic Programming
Medium
10
0.7%
1294Swap Sex of Employees
Database
Easy
10
0.8%
1295Strange Printer
String, Dynamic Programming
Hard
10
0.6%
1296N-ary Tree Level Order Traversal
Tree, Breadth-First Search
Medium
10
0.7%
1297Reaching Points
Math
Hard
10
0.3%
1298Rotated Digits
Math, Dynamic Programming
Medium
10
0.6%
1299Largest Triangle Area
Array, Math, Geometry
Easy
10
0.7%
1300Linked List Components
Array, Hash Table, Linked List
Medium
10
0.6%
1301Most Profit Assigning Work
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
10
0.6%
1302Robot Room Cleaner
Backtracking, Interactive
Hard
10
0.8%
1303Rectangle Overlap
Math, Geometry
Easy
10
0.5%
1304Shortest Path Visiting All Nodes
Dynamic Programming, Bit Manipulation, Breadth-First Search, Graph Theory, Bitmask
Hard
10
0.7%
1305Leaf-Similar Trees
Tree, Depth-First Search, Binary Tree
Easy
10
0.7%
1306Increasing Order Search Tree
Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
10
0.8%
1307Smallest Range II
Array, Math, Greedy, Sorting
Medium
10
0.4%
1308Knight Dialer
Dynamic Programming
Medium
10
0.6%
1309Largest Perimeter Triangle
Array, Math, Greedy, Sorting
Easy
10
0.6%
1310Longest Arithmetic Subsequence
Array, Hash Table, Binary Search, Dynamic Programming
Medium
10
0.5%
1311Minimum Score Triangulation of Polygon
Array, Dynamic Programming
Medium
10
0.7%
1312Last Substring in Lexicographical Order
Two Pointers, String
Hard
10
0.4%
1313Design A Leaderboard
Hash Table, Design, Sorting
Medium
10
0.7%
1314Delete Nodes And Return Forest
Array, Hash Table, Tree, Depth-First Search, Binary Tree
Medium
10
0.7%
1315Check If It Is a Straight Line
Array, Math, Geometry
Easy
10
0.4%
1316Group the People Given the Group Size They Belong To
Array, Hash Table, Greedy
Medium
10
0.9%
1317Convert Binary Number in a Linked List to Integer
Linked List, Math
Easy
10
0.8%
1318Minimum Number of Taps to Open to Water a Garden
Array, Dynamic Programming, Greedy
Hard
10
0.5%
1319Sort Integers by The Number of 1 Bits
Array, Bit Manipulation, Sorting, Counting
Easy
10
0.8%
1320Product of the Last K Numbers
Array, Math, Design, Data Stream, Prefix Sum
Medium
10
0.6%
1321Design Underground System
Hash Table, String, Design
Medium
10
0.7%
1322Least Number of Unique Integers after K Removals
Array, Hash Table, Greedy, Sorting, Counting
Medium
10
0.6%
1323Dot Product of Two Sparse Vectors
Array, Hash Table, Two Pointers, Design
Medium
10
0.9%
1324Minimum Number of Removals to Make Mountain Array
Array, Binary Search, Dynamic Programming, Greedy
Hard
10
0.5%
1325Minimum Deletions to Make Character Frequencies Unique
Hash Table, String, Greedy, Sorting
Medium
10
0.6%
1326Count of Matches in Tournament
Math, Simulation
Easy
10
0.9%
1327Construct the Lexicographically Largest Valid Sequence
Array, Backtracking
Medium
10
0.7%
1328Check if One String Swap Can Make Strings Equal
Hash Table, String, Counting
Easy
10
0.5%
1329Find Center of Star Graph
Graph Theory
Easy
10
0.9%
1330Substrings of Size Three with Distinct Characters
Hash Table, String, Sliding Window, Counting
Easy
10
0.8%
1331Process Tasks Using Servers
Array, Heap (Priority Queue)
Medium
10
0.4%
1332Detect Squares
Array, Hash Table, Design, Counting, Data Stream
Medium
10
0.5%
1333Maximum Employees to Be Invited to a Meeting
Array, Dynamic Programming, Depth-First Search, Graph Theory, Topological Sort
Hard
10
0.6%
1334Merge Nodes in Between Zeros
Linked List, Simulation
Medium
10
0.9%
1335Escape the Spreading Fire
Array, Binary Search, Breadth-First Search, Matrix
Hard
10
0.4%
1336Decode the Message
Hash Table, String
Easy
10
0.9%
1337Largest Positive Integer That Exists With Its Negative
Array, Hash Table, Two Pointers, Sorting
Easy
10
0.7%
1338Count Subarrays With Fixed Bounds
Array, Queue, Sliding Window, Monotonic Queue
Hard
10
0.7%
1339Sliding Subarray Beauty
Array, Hash Table, Sliding Window
Medium
10
0.4%
1340Cache With Time LimitMedium
10
0.8%
1341Count Subarrays Where Max Element Appears at Least K Times
Array, Sliding Window
Medium
10
0.6%
1342Super Ugly Number
Array, Math, Dynamic Programming
Medium
10
0.5%
1343Check if the Rectangle Corner Is Reachable
Array, Math, Depth-First Search, Breadth-First Search, Union-Find, Geometry
Hard
10
0.3%
1344Find Servers That Handled Most Number of Requests
Array, Heap (Priority Queue), Simulation, Ordered Set
Hard
10
0.5%
1345Minimum Operations to Make All Array Elements Equal
Array, Binary Search, Sorting, Prefix Sum
Medium
10
0.4%
1346Number of Good Ways to Split a String
Hash Table, String, Dynamic Programming, Bit Manipulation, Prefix Sum
Medium
10
0.7%
1347Minimum Obstacle Removal to Reach Corner
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
10
0.7%
1348All Ancestors of a Node in a Directed Acyclic Graph
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
10
0.6%
1349Robot Collisions
Array, Stack, Sorting, Simulation
Hard
10
0.6%
1350Minimum String Length After Removing Substrings
String, Stack, Simulation
Easy
10
0.8%
1351Prime Palindrome
Math, Number Theory
Medium
10
0.3%
1352Numbers With Same Consecutive Differences
Backtracking, Breadth-First Search
Medium
10
0.6%
1353Sort the People
Array, Hash Table, String, Sorting
Easy
10
0.8%
1354Finding the Users Active Minutes
Array, Hash Table
Medium
10
0.8%
1355Design Log Storage System
Hash Table, String, Design, Ordered Set
Medium
10
0.6%
1356Lexicographically Smallest Beautiful String
String, Greedy
Hard
10
0.4%
1357Largest Combination With Bitwise AND Greater Than Zero
Array, Hash Table, Bit Manipulation, Counting
Medium
10
0.8%
1358DI String Match
Array, Two Pointers, String, Greedy
Easy
10
0.8%
1359Maximum Number of Removable Characters
Array, Two Pointers, String, Binary Search
Medium
10
0.5%
1360Zigzag Iterator
Array, Design, Queue, Iterator
Medium
10
0.7%
1361Rearrange Array to Maximize Prefix Score
Array, Greedy, Sorting, Prefix Sum
Medium
10
0.4%
1362Minimum Cost to Make at Least One Valid Path in a Grid
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
10
0.7%
1363Paint House IV
Array, Dynamic Programming
Medium
10
0.5%
1364Most Profitable Path in a Tree
Array, Tree, Depth-First Search, Breadth-First Search, Graph Theory
Medium
10
0.7%
1365Apply Operations to Make All Array Elements Equal to Zero
Array, Prefix Sum
Medium
10
0.3%
1366Max Chunks To Make Sorted II
Array, Stack, Greedy, Sorting, Monotonic Stack
Hard
10
0.5%
1367Stock Price Fluctuation
Hash Table, Design, Heap (Priority Queue), Data Stream, Ordered Set
Medium
10
0.5%
1368Design Excel Sum Formula
Array, Hash Table, String, Graph Theory, Design, Topological Sort, Matrix
Hard
10
0.4%
1369Count Univalue Subtrees
Tree, Depth-First Search, Binary Tree
Medium
10
0.6%
1370Bitwise ORs of Subarrays
Array, Dynamic Programming, Bit Manipulation
Medium
10
0.6%
1371Closest Prime Numbers in Range
Math, Number Theory
Medium
10
0.5%
1372Count Palindromic Subsequences
String, Dynamic Programming
Hard
10
0.4%
1373Minimum Absolute Difference
Array, Sorting
Easy
10
0.8%
1374Teemo Attacking
Array, Simulation
Easy
10
0.6%
1375Market Analysis I
Database
Medium
10
0.6%
1376Expression Add Operators
Math, String, Backtracking
Hard
10
0.4%
1377Count Subarrays With Score Less Than K
Array, Binary Search, Sliding Window, Prefix Sum
Hard
10
0.6%
1378Find the Middle Index in Array
Array, Prefix Sum
Easy
10
0.7%
1379Binary Watch
Backtracking, Bit Manipulation
Easy
10
0.7%
1380Range Sum Query 2D - Mutable
Array, Design, Binary Indexed Tree, Segment Tree, Matrix
Medium
10
0.5%
1381Number of Segments in a String
String
Easy
10
0.4%
1382Minimum Cuts to Divide a Circle
Math, Geometry
Easy
10
0.6%
1383Divisible and Non-divisible Sums Difference
Math
Easy
10
0.9%
1384Maximum Height by Stacking Cuboids
Array, Dynamic Programming, Sorting
Hard
10
0.6%
1385Find the Lexicographically Largest String From the Box I
Two Pointers, String, Enumeration
Medium
10
0.4%
1386Average of Levels in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
10
0.7%
1387Shortest Distance to a Character
Array, Two Pointers, String
Easy
10
0.7%
1388Number of Islands II
Array, Hash Table, Union-Find
Hard
10
0.4%
1389Mirror Reflection
Math, Geometry, Number Theory
Medium
10
0.6%
1390Cherry Pickup
Array, Dynamic Programming, Matrix
Hard
10
0.4%
1391Minimum Operations to Reduce an Integer to 0
Dynamic Programming, Greedy, Bit Manipulation
Medium
10
0.6%
1392Delete Characters to Make Fancy String
String
Easy
10
0.7%
1393Maximum Unique Subarray Sum After Deletion
Array, Hash Table, Greedy
Easy
10
0.4%
1394Jump Game III
Array, Depth-First Search, Breadth-First Search
Medium
10
0.7%
1395A Number After a Double Reversal
Math
Easy
10
0.8%
1396Rearranging Fruits
Array, Hash Table, Greedy, Sort
Hard
10
0.6%
1397Rectangle Area
Math, Geometry
Medium
10
0.5%
1398Minimum Operations to Convert All Elements to Zero
Array, Hash Table, Stack, Greedy, Monotonic Stack
Medium
10
0.5%
1399Sort Matrix by Diagonals
Array, Sorting, Matrix
Medium
10
0.8%
1400Minimum Operations to Equalize Binary String
Math, String, Breadth-First Search, Union-Find, Ordered Set
Hard
10
0.5%
1401Minimum Number of People to Teach
Array, Hash Table, Greedy
Medium
10
0.7%
1402Find the Minimum Amount of Time to Brew Potions
Array, Simulation, Prefix Sum
Medium
10
0.6%
1403Maximum Number of Distinct Elements After Operations
Array, Greedy, Sorting
Medium
10
0.5%
1404Maximum Frequency of an Element After Performing Operations I
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Medium
10
0.4%
1405Make Array Elements Equal to Zero
Array, Simulation, Prefix Sum
Easy
10
0.7%
1406Find X-Sum of All K-Long Subarrays I
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Easy
10
0.8%
1407Maximize the Minimum Powered City
Array, Binary Search, Greedy, Queue, Sliding Window, Prefix Sum
Hard
10
0.6%
1408Paths in Matrix Whose Sum Is Divisible by K
Array, Dynamic Programming, Matrix
Hard
10
0.6%
1409Maximum Running Time of N Computers
Array, Binary Search, Greedy, Sorting
Hard
10
0.6%
1410Count Partitions With Max-Min Difference at Most K
Array, Dynamic Programming, Queue, Sliding Window, Prefix Sum, Monotonic Queue
Medium
10
0.6%
1411Best Time to Buy and Sell Stock using Strategy
Array, Sliding Window, Prefix Sum
Medium
10
0.6%
1412Construct Product Matrix
Array, Matrix, Prefix Sum
Medium
10
0.5%
1413Delete Columns to Make Sorted II
Array, String, Greedy
Medium
10
0.5%
1414Paint House
Array, Dynamic Programming
Medium
10
0.6%
1415Partition Array Into Three Parts With Equal Sum
Array, Greedy
Easy
10
0.4%
1416Ones and Zeroes
Array, String, Dynamic Programming
Medium
10
0.5%
1417Number of Ways to Paint N × 3 Grid
Dynamic Programming
Hard
10
0.8%
1418Construct the Minimum Bitwise Array I
Array, Bit Manipulation
Easy
10
0.9%
1419Minimum Cost Path with Teleportations
Array, Dynamic Programming, Matrix
Hard
10
0.5%
1420Largest Magic Square
Array, Matrix, Prefix Sum
Medium
10
0.8%
1421Smallest String Starting From Leaf
String, Backtracking, Tree, Depth-First Search, Binary Tree
Medium
10
0.6%
1422Binary Gap
Bit Manipulation
Easy
10
0.7%
1423Check if Binary String Has at Most One Segment of Ones
String
Easy
10
0.5%
1424Find Unique Binary String
Array, Hash Table, String, Backtracking
Medium
10
0.8%
1425Get Biggest Three Rhombus Sums in a Grid
Array, Math, Sorting, Heap (Priority Queue), Matrix, Prefix Sum
Medium
10
0.7%
1426Maximum Non Negative Product in a Matrix
Array, Dynamic Programming, Matrix
Medium
10
0.5%
1427Daily Leads and Partners
Database
Easy
10
0.9%
1428Web Crawler
String, Depth-First Search, Breadth-First Search, Interactive
Medium
10
0.7%
1429Largest Palindromic Number
Hash Table, String, Greedy, Counting
Medium
10
0.4%
1430Minimum Absolute Distance Between Mirror Pairs
Array, Hash Table, Math
Medium
10
0.6%
1431Two Furthest Houses With Different Colors
Array, Greedy
Easy
10
0.7%
1432Sum of Distances
Array, Hash Table, Prefix Sum
Medium
10
0.5%
1433Maximum Score From Grid Operations
Array, Dynamic Programming, Matrix, Prefix Sum
Hard
10
0.6%
1434First Completely Painted Row or Column
Array, Hash Table, Matrix
Medium
10
0.6%
1435Maximum Number of Jumps to Reach the Last Index
Array, Dynamic Programming
Medium
10
0.5%
1436Total Waviness of Numbers in Range II
Math, Dynamic Programming
Hard
10
0.6%
1437Maximum Total Subarray Value I
Array, Greedy
Medium
10
0.7%
1438Maximum Number of Balloons
Hash Table, String, Counting
Easy
10
0.6%
1439Graph Valid Tree
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
7
0.5%
1440Closest Binary Search Tree Value II
Two Pointers, Stack, Tree, Depth-First Search, Binary Search Tree, Heap (Priority Queue), Binary Tree
Hard
7
0.6%
1441Maximum Product of Word Lengths
Array, String, Bit Manipulation
Medium
7
0.6%
1442Maximum Size Subarray Sum Equals k
Array, Hash Table, Prefix Sum
Medium
7
0.5%
1443Patching Array
Array, Greedy
Hard
7
0.5%
1444Plus One Linked List
Linked List, Math
Medium
7
0.6%
1445Shuffle an Array
Array, Math, Design, Randomized
Medium
7
0.6%
1446Mini Parser
String, Stack, Depth-First Search
Medium
7
0.4%
1447Longest Absolute File Path
String, Stack, Depth-First Search
Medium
7
0.5%
1448Random Pick Index
Hash Table, Math, Reservoir Sampling, Randomized
Medium
7
0.7%
1449Convert a Number to Hexadecimal
Math, String, Bit Manipulation
Easy
7
0.5%
1450Maximum XOR of Two Numbers in an Array
Array, Hash Table, Bit Manipulation, Trie
Medium
7
0.5%
1451Circular Array Loop
Array, Hash Table, Two Pointers
Medium
7
0.4%
1452Minimum Moves to Equal Array Elements II
Array, Math, Sorting
Medium
7
0.6%
1453Validate IP Address
String
Medium
7
0.3%
1454Keyboard Row
Array, Hash Table, String
Easy
7
0.7%
1455Shopping Offers
Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
Medium
7
0.5%
1456Number of Longest Increasing Subsequence
Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
Medium
7
0.5%
1457Repeated String Match
String, String Matching
Medium
7
0.4%
1458Range Module
Design, Segment Tree, Ordered Set
Hard
7
0.5%
1459My Calendar II
Array, Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set
Medium
7
0.6%
1460Design HashSet
Array, Hash Table, Linked List, Design, Hash Function
Easy
7
0.7%
1461Binary Tree Pruning
Tree, Depth-First Search, Binary Tree
Medium
7
0.7%
1462Count Unique Characters of All Substrings of a Given String
Hash Table, String, Dynamic Programming
Hard
7
0.5%
1463Flipping an Image
Array, Two Pointers, Bit Manipulation, Matrix, Simulation
Easy
7
0.8%
1464Super Egg Drop
Math, Binary Search, Dynamic Programming
Hard
7
0.3%
1465Beautiful Array
Array, Math, Divide and Conquer
Medium
7
0.7%
1466Two City Scheduling
Array, Greedy, Sorting
Medium
7
0.7%
1467Stream of Characters
Array, String, Design, Trie, Data Stream
Hard
7
0.5%
1468Longest String Chain
Array, Hash Table, Two Pointers, String, Dynamic Programming, Sorting
Medium
7
0.6%
1469Height Checker
Array, Sorting, Counting Sort
Easy
7
0.8%
1470Meeting Scheduler
Array, Two Pointers, Sorting
Medium
7
0.6%
1471Duplicate Zeros
Array, Two Pointers
Easy
7
0.5%
1472Element Appearing More Than 25% In Sorted Array
Array
Easy
7
0.6%
1473Sort the Matrix Diagonally
Array, Sorting, Matrix
Medium
7
0.8%
1474Remove Zero Sum Consecutive Nodes from Linked List
Hash Table, Linked List
Medium
7
0.5%
1475Number of Days Between Two Dates
Math, String
Easy
7
0.5%
1476Three Consecutive Odds
Array
Easy
7
0.7%
1477Kth Ancestor of a Tree Node
Binary Search, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search, Breadth-First Search, Design
Hard
7
0.4%
1478Reverse Substrings Between Each Pair of Parentheses
String, Stack
Medium
7
0.7%
1479Path with Maximum Probability
Array, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
7
0.7%
1480Path with Maximum Gold
Array, Backtracking, Matrix
Medium
7
0.7%
1481Report Contiguous Dates
Database
Hard
7
0.6%
1482XOR Queries of a Subarray
Array, Bit Manipulation, Prefix Sum
Medium
7
0.8%
1483Maximum 69 Number
Math, Greedy
Easy
7
0.8%
1484Minimum Number of Steps to Make Two Strings Anagram
Hash Table, String, Counting
Medium
7
0.8%
1485Time Needed to Inform All Employees
Tree, Depth-First Search, Breadth-First Search
Medium
7
0.6%
1486Destination City
Array, Hash Table, String
Easy
7
0.8%
1487Count Odd Numbers in an Interval Range
Math
Easy
7
0.5%
1488Count Good Triplets
Array, Enumeration
Easy
7
0.9%
1489Make The String Great
String, Stack
Easy
7
0.7%
1490Widest Vertical Area Between Two Points Containing No Points
Array, Sorting
Easy
7
0.9%
1491Merge In Between Linked Lists
Linked List
Medium
7
0.8%
1492Get Maximum in Generated Array
Array, Simulation
Easy
7
0.5%
1493Determine if Two Strings Are Close
Hash Table, String, Sorting, Counting
Medium
7
0.5%
1494Check If Two String Arrays are Equivalent
Array, String
Easy
7
0.9%
1495Calculate Money in Leetcode Bank
Math
Easy
7
0.8%
1496Maximum Score From Removing Substrings
String, Stack, Greedy
Medium
7
0.7%
1497Remove One Element to Make the Array Strictly Increasing
Array
Easy
7
0.3%
1498Convert 1D Array Into 2D Array
Array, Matrix, Simulation
Easy
7
0.7%
1499Minimum Number of Moves to Seat Everyone
Array, Greedy, Sorting, Counting Sort
Easy
7
0.9%
1500Time Needed to Buy Tickets
Array, Queue, Simulation
Easy
7
0.7%
1501Minimum Bit Flips to Convert Number
Bit Manipulation
Easy
7
0.9%
1502Find Closest Number to Zero
Array
Easy
7
0.5%
1503Longest Path With Different Adjacent Characters
Array, String, Tree, Depth-First Search, Graph Theory, Topological Sort
Hard
7
0.5%
1504Longest Cycle in a Graph
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
7
0.5%
1505Minimize Maximum of Array
Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
Medium
7
0.5%
1506Convert the Temperature
Math
Easy
7
0.9%
1507Count the Number of Good Subarrays
Array, Hash Table, Sliding Window
Medium
7
0.7%
1508Apply Transform Over Each Element in ArrayEasy
7
0.9%
1509Number of Employees Who Met the Target
Array
Easy
7
0.9%
1510Display the First Three RowsEasy
7
0.9%
1511Find Words Containing Character
Array, String
Easy
7
0.9%
1512Minimum Number of Operations to Make Array XOR Equal to K
Array, Bit Manipulation
Medium
7
0.9%
1513Minimum Array End
Bit Manipulation
Medium
7
0.6%
1514Group Sold Products By The Date
Database
Easy
7
0.8%
1515Longest Turbulent Subarray
Array, Dynamic Programming, Sliding Window
Medium
7
0.5%
1516Minimum Number of Days to Disconnect Island
Array, Depth-First Search, Breadth-First Search, Matrix, Strongly Connected Component
Hard
7
0.6%
1517Degree of an Array
Array, Hash Table
Easy
7
0.6%
1518HTML Entity Parser
Hash Table, String
Medium
7
0.5%
1519Dinner Plate Stacks
Hash Table, Stack, Design, Heap (Priority Queue)
Hard
7
0.3%
1520Maximize Score of Numbers in Ranges
Array, Binary Search, Greedy, Sorting
Medium
7
0.4%
1521Check if Two Chessboard Squares Have the Same Color
Math, String
Easy
7
0.7%
1522Longest Strictly Increasing or Strictly Decreasing Subarray
Array
Easy
7
0.6%
1523Count the Number of Inversions
Array, Dynamic Programming
Hard
7
0.3%
1524Uncommon Words from Two Sentences
Hash Table, String, Counting
Easy
7
0.8%
1525Sort ByEasy
7
0.8%
1526Largest Sum of Averages
Array, Dynamic Programming, Prefix Sum
Medium
7
0.6%
1527Minimize Max Distance to Gas Station
Array, Binary Search
Hard
7
0.5%
1528The Maze
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
7
0.6%
1529Maximal Score After Applying K Operations
Array, Greedy, Heap (Priority Queue)
Medium
7
0.6%
1530Split a String Into the Max Number of Unique Substrings
Hash Table, String, Backtracking
Medium
7
0.7%
1531Find Occurrences of an Element in an Array
Array, Hash Table
Medium
7
0.7%
1532Grid Game
Array, Matrix, Prefix Sum
Medium
7
0.6%
1533Flip Columns For Maximum Number of Equal Rows
Array, Hash Table, Matrix
Medium
7
0.8%
1534Reshape Data: PivotEasy
7
0.8%
1535Minimum Operations to Make a Subsequence
Array, Hash Table, Binary Search, Greedy
Hard
7
0.5%
1536Minimum Time to Visit a Cell In a Grid
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Hard
7
0.6%
1537Find Building Where Alice and Bob Can Meet
Array, Binary Search, Stack, Binary Indexed Tree, Segment Tree, Heap (Priority Queue), Monotonic Stack
Hard
7
0.5%
1538Count Ways To Build Good Strings
Dynamic Programming
Medium
7
0.6%
1539Employee Importance
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
7
0.7%
1540Construct K Palindrome Strings
Hash Table, String, Greedy, Counting
Medium
7
0.7%
1541Minimum Time to Collect All Apples in a Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
7
0.6%
1542Maximum Number of Fish in a Grid
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
7
0.7%
1543Maximum Ascending Subarray Sum
Array
Easy
7
0.7%
1544Tuple with Same Product
Array, Hash Table, Counting
Medium
7
0.7%
1545Find the Number of Distinct Colors Among the Balls
Array, Hash Table, Simulation
Medium
7
0.5%
1546Minimum Operations to Exceed Threshold Value II
Array, Heap (Priority Queue), Simulation
Medium
7
0.5%
1547Escape a Large Maze
Array, Hash Table, Depth-First Search, Breadth-First Search
Hard
7
0.4%
1548Divide Nodes Into the Maximum Number of Groups
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
7
0.7%
1549Minimum Operations to Make the Array Increasing
Array, Greedy
Easy
7
0.8%
1550Rank Teams by Votes
Array, Hash Table, String, Sorting, Counting
Medium
7
0.6%
1551Sentence Similarity II
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find
Medium
7
0.5%
1552Minimum Recolors to Get K Consecutive Black Blocks
String, Sliding Window
Easy
7
0.7%
1553Sliding Puzzle
Array, Dynamic Programming, Backtracking, Breadth-First Search, Memoization, Matrix
Hard
7
0.7%
1554N-ary Tree Preorder Traversal
Stack, Tree, Depth-First Search
Easy
7
0.8%
1555Divide Array Into Equal Pairs
Array, Hash Table, Bit Manipulation, Counting
Easy
7
0.8%
1556Parallel Courses
Graph Theory, Topological Sort
Medium
7
0.6%
1557Data Stream as Disjoint Intervals
Hash Table, Binary Search, Union-Find, Design, Data Stream, Ordered Set
Hard
7
0.6%
1558Find the Kth Smallest Sum of a Matrix With Sorted Rows
Array, Binary Search, Heap (Priority Queue), Matrix
Hard
7
0.6%
1559Check if Grid can be Cut into Sections
Array, Sorting
Medium
7
0.7%
1560Count of Substrings Containing Every Vowel and K Consonants II
Hash Table, String, Sliding Window
Medium
7
0.4%
1561Binary Tree Tilt
Tree, Depth-First Search, Binary Tree
Easy
7
0.7%
1562Number of Adjacent Elements With the Same Color
Array
Medium
7
0.6%
1563Alternating Groups I
Array, Sliding Window
Easy
7
0.7%
1564Finding Pairs With a Certain Sum
Array, Hash Table, Design
Medium
7
0.6%
1565Count the Number of Ideal Arrays
Math, Dynamic Programming, Combinatorics, Number Theory
Hard
7
0.6%
1566Push Dominoes
Two Pointers, String, Dynamic Programming
Medium
7
0.6%
1567Find Minimum Time to Reach Last Room II
Array, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
7
0.7%
1568Count Collisions of Monkeys on a Polygon
Math, Recursion
Medium
7
0.3%
1569Max Pair Sum in an Array
Array, Hash Table
Easy
7
0.6%
1570Maximum Difference Between Even and Odd Frequency II
String, Sliding Window, Enumeration, Prefix Sum
Hard
7
0.5%
1571Maximum Difference Between Adjacent Elements in a Circular Array
Array
Easy
7
0.8%
1572Surface Area of 3D Shapes
Array, Math, Geometry, Matrix
Easy
7
0.7%
1573Check if All Characters Have Equal Number of Occurrences
Hash Table, String, Counting
Easy
7
0.8%
1574Check if All the Integers in a Range Are Covered
Array, Hash Table, Prefix Sum
Easy
7
0.5%
1575Count Nodes Equal to Average of Subtree
Tree, Depth-First Search, Binary Tree
Medium
7
0.9%
1576Longest Binary Subsequence Less Than or Equal to K
String, Dynamic Programming, Greedy, Memoization
Medium
7
0.5%
1577Minimum Distance Between BST Nodes
Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
7
0.6%
1578Longest Nice Substring
Hash Table, String, Divide and Conquer, Bit Manipulation, Sliding Window
Easy
7
0.6%
1579Find the K-th Character in String Game II
Math, Bit Manipulation, Recursion
Hard
7
0.5%
1580Reschedule Meetings for Maximum Free Time II
Array, Greedy, Enumeration
Medium
7
0.6%
1581The Earliest and Latest Rounds Where Players Compete
Dynamic Programming, Memoization
Hard
7
0.7%
1582Number of Pairs of Interchangeable Rectangles
Array, Hash Table, Math, Counting, Number Theory
Medium
7
0.5%
1583Minimize Malware Spread
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
7
0.4%
1584Construct the Rectangle
Math
Easy
7
0.6%
1585Check Balanced String
String
Easy
7
0.8%
1586Longest Non-decreasing Subarray From Two Arrays
Array, Dynamic Programming
Medium
7
0.3%
1587Maximum Fruits Harvested After at Most K Steps
Array, Binary Search, Sliding Window, Prefix Sum
Hard
7
0.6%
1588Patients With a Condition
Database
Easy
7
0.4%
1589Analyze Organization Hierarchy
Database
Hard
7
0.6%
1590Matchsticks to Square
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
7
0.4%
1591Distinct Subsequences II
String, Dynamic Programming
Hard
7
0.4%
1592Count Salary Categories
Database
Medium
7
0.6%
1593Minimum Time Visiting All Points
Array, Math, Geometry
Easy
7
0.8%
1594Remove Boxes
Array, Dynamic Programming, Memoization
Hard
7
0.5%
1595Maximum Number of Occurrences of a Substring
Hash Table, String, Sliding Window
Medium
7
0.5%
1596Find Closest Person
Math
Easy
7
0.9%
1597Find Most Frequent Vowel and Consonant
Hash Table, String, Counting
Easy
7
0.9%
1598Maximum Number of Words You Can Type
Hash Table, String
Easy
7
0.8%
1599Unique Email Addresses
Array, Hash Table, String
Easy
7
0.7%
1600Ugly Number III
Math, Binary Search, Combinatorics, Number Theory
Medium
7
0.3%
1601Friends Of Appropriate Ages
Array, Two Pointers, Binary Search, Sorting
Medium
7
0.5%
1602Longest Subsequence With Limited Sum
Array, Binary Search, Greedy, Sorting, Prefix Sum
Easy
7
0.7%
1603Maximum Frequency of an Element After Performing Operations II
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Hard
7
0.5%
1604Smallest Number With All Set Bits
Math, Bit Manipulation
Easy
7
0.8%
1605Number of Good Paths
Array, Hash Table, Tree, Union-Find, Graph Theory, Sorting
Hard
7
0.6%
1606The Two Sneaky Numbers of Digitville
Array, Hash Table, Math
Easy
7
0.9%
1607Maximum and Minimum Sums of at Most Size K Subsequences
Array, Math, Dynamic Programming, Sorting, Combinatorics
Medium
7
0.2%
1608Minimum Time to Make Rope Colorful
Array, String, Dynamic Programming, Greedy
Medium
7
0.7%
1609Power Grid Maintenance
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Heap (Priority Queue), Ordered Set
Medium
7
0.6%
1610Count Operations to Obtain Zero
Math, Simulation
Easy
7
0.8%
1611Minimum Number of Operations to Make All Array Elements Equal to 1
Array, Math, Number Theory
Medium
7
0.5%
1612Maximum Number of Operations to Move Ones to the End
String, Greedy, Counting
Medium
7
0.7%
1613Find Minimum Operations to Make All Elements Divisible by Three
Array, Math
Easy
7
0.9%
1614Smallest Integer Divisible by K
Hash Table, Math
Medium
7
0.5%
1615Car Fleet II
Array, Math, Stack, Heap (Priority Queue), Monotonic Stack
Hard
7
0.6%
1616Sign of the Product of an Array
Array, Math
Easy
7
0.6%
1617Minimum Operations to Make Array Sum Divisible by K
Array, Math
Easy
7
0.9%
1618Count the Digits That Divide a Number
Math
Easy
7
0.9%
1619Count Largest Group
Hash Table, Math, Counting
Easy
7
0.7%
1620Find Followers Count
Database
Easy
7
0.7%
1621Perfect Rectangle
Array, Hash Table, Math, Geometry, Sweep Line
Hard
7
0.4%
1622Split Array With Same Average
Array, Hash Table, Math, Dynamic Programming, Bit Manipulation, Bitmask
Hard
7
0.3%
1623Minimize Maximum Pair Sum in Array
Array, Two Pointers, Greedy, Sorting
Medium
7
0.8%
1624Count Symmetric Integers
Math, Enumeration
Easy
7
0.8%
1625Divide an Array Into Subarrays With Minimum Cost II
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
7
0.5%
1626Minimum Edge Reversals So Every Node Is Reachable
Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory
Hard
7
0.6%
1627Minimum Absolute Difference in BST
Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
7
0.6%
1628Longest Balanced Subarray II
Array, Hash Table, Divide and Conquer, Segment Tree, Prefix Sum
Hard
7
0.3%
1629Happy Students
Array, Sorting, Enumeration
Medium
7
0.5%
1630Binary Number with Alternating Bits
Bit Manipulation
Easy
7
0.7%
1631Customer Placing the Largest Number of Orders
Database
Easy
7
0.6%
1632Satisfiability of Equality Equations
Array, String, Union-Find, Graph Theory
Medium
7
0.5%
1633Minimum Swaps to Arrange a Binary Grid
Array, Greedy, Matrix
Medium
7
0.7%
1634Minimum Number of Flips to Make the Binary String Alternating
String, Dynamic Programming, Sliding Window
Medium
7
0.5%
1635Merge BSTs to Create Single BST
Array, Hash Table, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Hard
7
0.4%
1636Find All Possible Stable Binary Arrays II
Dynamic Programming, Prefix Sum
Hard
7
0.6%
1637Complement of Base 10 Integer
Bit Manipulation
Easy
7
0.6%
1638Maximize Spanning Tree Stability with Upgrades
Binary Search, Greedy, Union-Find, Graph Theory, Minimum Spanning Tree
Hard
7
0.7%
1639Minimum Number of Seconds to Make Mountain Height Zero
Array, Math, Binary Search, Greedy, Heap (Priority Queue)
Medium
7
0.6%
1640Fancy Sequence
Math, Design, Segment Tree, Number Theory
Hard
7
0.4%
1641Largest Submatrix With Rearrangements
Array, Greedy, Sorting, Matrix
Medium
7
0.8%
1642Maximum Amount of Money Robot Can Earn
Array, Dynamic Programming, Matrix
Medium
7
0.5%
1643Maximum Walls Destroyed by Robots
Array, Binary Search, Dynamic Programming, Sorting
Hard
7
0.5%
1644XOR After Range Multiplication Queries I
Array, Divide and Conquer, Simulation, Prefix Sum
Medium
7
0.7%
1645XOR After Range Multiplication Queries II
Array, Divide and Conquer, Prefix Sum
Hard
7
0.5%
1646Find Mode in Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
7
0.6%
1647Shortest Distance to Target String in a Circular Array
Array, String
Easy
7
0.7%
1648Closest Equal Element Queries
Array, Hash Table, Binary Search
Medium
7
0.5%
1649Subtract the Product and Sum of Digits of an Integer
Math
Easy
7
0.9%
1650Minimum Operations to Make a Uni-Value Grid
Array, Math, Sorting, Matrix
Medium
7
0.7%
1651Score After Flipping Matrix
Array, Greedy, Bit Manipulation, Matrix
Medium
7
0.8%
1652Jump Game IX
Array, Dynamic Programming
Medium
7
0.5%
1653Minimum Jumps to Reach End via Prime Teleportation
Array, Hash Table, Math, Breadth-First Search, Number Theory
Medium
7
0.4%
1654Reshape the Matrix
Array, Matrix, Simulation
Easy
7
0.7%
1655Parallel Courses II
Dynamic Programming, Bit Manipulation, Graph Theory, Bitmask
Hard
7
0.3%
1656Jump Game V
Array, Dynamic Programming, Sorting
Hard
7
0.8%
1657Longest Common Suffix Queries
Array, String, Trie
Hard
7
0.5%
1658Minimum Number Game
Array, Sorting, Heap (Priority Queue), Simulation
Easy
7
0.9%
1659Left and Right Sum Differences
Array, Prefix Sum
Easy
7
0.9%
1660Bag of Tokens
Array, Two Pointers, Greedy, Sorting
Medium
7
0.6%
1661Number of Ways to Assign Edge Weights I
Math, Tree, Depth-First Search
Medium
7
0.6%
1662Longest Substring with At Most Two Distinct Characters
Hash Table, String, Sliding Window
Medium
5
0.6%
1663Hamming Distance
Bit Manipulation
Easy
5
0.8%
1664Magical String
Two Pointers, String
Medium
5
0.6%
1665Beautiful Arrangement
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
5
0.6%
1666Erect the Fence
Array, Math, Geometry
Hard
5
0.5%
1667Sales Person
Database
Easy
5
0.7%
1668Print Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
5
0.7%
1669Minimum ASCII Delete Sum for Two Strings
String, Dynamic Programming
Medium
5
0.7%
1670Longest Word in Dictionary
Array, Hash Table, String, Trie, Sorting
Medium
5
0.5%
1671Count Different Palindromic Subsequences
String, Dynamic Programming
Hard
5
0.5%
1672Convert Binary Search Tree to Sorted Doubly Linked List
Linked List, Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree, Doubly-Linked List
Medium
5
0.7%
1673Letter Case Permutation
String, Backtracking, Bit Manipulation
Medium
5
0.8%
1674Sum of Distances in Tree
Dynamic Programming, Tree, Depth-First Search, Graph Theory
Hard
5
0.7%
1675Similar String Groups
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find
Hard
5
0.6%
1676Longest Mountain in Array
Array, Two Pointers, Dynamic Programming, Enumeration
Medium
5
0.4%
1677Advantage Shuffle
Array, Two Pointers, Greedy, Sorting
Medium
5
0.5%
1678Decoded String at Index
String, Stack
Medium
5
0.4%
1679Spiral Matrix III
Array, Matrix, Simulation
Medium
5
0.8%
1680Construct Binary Tree from Preorder and Postorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
5
0.8%
1681Flip Equivalent Binary Trees
Tree, Depth-First Search, Binary Tree
Medium
5
0.7%
1682Check Completeness of a Binary Tree
Tree, Breadth-First Search, Binary Tree
Medium
5
0.6%
1683Minimum Number of K Consecutive Bit Flips
Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum
Hard
5
0.6%
1684Number of Enclaves
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
5
0.7%
1685Lowest Common Ancestor of Deepest Leaves
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
5
0.8%
1686Minimum Moves to Reach Target Score
Math, Greedy
Medium
5
0.5%
1687Number of Closed Islands
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
5
0.7%
1688Longest ZigZag Path in a Binary Tree
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Medium
5
0.7%
1689Linked List in Binary Tree
Linked List, Tree, Depth-First Search, Binary Tree
Medium
5
0.5%
1690Find a Corresponding Node of a Binary Tree in a Clone of That Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
5
0.9%
1691Create Target Array in the Given Order
Array, Simulation
Easy
5
0.9%
1692Diagonal Traverse II
Array, Sorting, Heap (Priority Queue)
Medium
5
0.6%
1693String Compression II
String, Dynamic Programming
Hard
5
0.5%
1694Minimum Suffix Flips
String, Greedy
Medium
5
0.7%
1695Maximum Number of Coins You Can Get
Array, Math, Greedy, Sorting, Game Theory
Medium
5
0.8%
1696Sum of All Odd Length Subarrays
Array, Math, Prefix Sum
Easy
5
0.8%
1697Special Array With X Elements Greater Than or Equal X
Array, Binary Search, Sorting
Easy
5
0.7%
1698Maximum Repeating Substring
String, Dynamic Programming, String Matching
Easy
5
0.4%
1699Average Waiting Time
Array, Simulation
Medium
5
0.7%
1700Count Items Matching a Rule
Array, String
Easy
5
0.9%
1701Single-Threaded CPU
Array, Sorting, Heap (Priority Queue)
Medium
5
0.5%
1702Sorting the Sentence
String, Sorting
Easy
5
0.8%
1703Minimum Non-Zero Product of the Array Elements
Math, Greedy, Recursion
Medium
5
0.4%
1704Minimum Number of Work Sessions to Finish the Tasks
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
5
0.4%
1705Find All People With Secret
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Sorting
Hard
5
0.5%
1706Remove Digit From Number to Maximize Result
String, Greedy, Enumeration
Easy
5
0.5%
1707Equal Row and Column Pairs
Array, Hash Table, Matrix, Simulation
Medium
5
0.7%
1708Minimum Number of Operations to Make Arrays Similar
Array, Greedy, Sorting
Hard
5
0.6%
1709Split Message Based on Limit
String, Enumeration
Hard
5
0.4%
1710Difference Between Element Sum and Digit Sum of an Array
Array, Math
Easy
5
0.9%
1711Maximum Subsequence Score
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
5
0.5%
1712Take Gifts From the Richest Pile
Array, Heap (Priority Queue), Simulation
Easy
5
0.8%
1713The Number of Beautiful Subsets
Array, Hash Table, Math, Dynamic Programming, Backtracking, Sorting, Combinatorics
Medium
5
0.5%
1714SleepEasy
5
0.9%
1715Function CompositionEasy
5
0.9%
1716Buy Two Chocolates
Array, Greedy, Sorting
Easy
5
0.7%
1717Event EmitterMedium
5
0.8%
1718Painting the Walls
Array, Dynamic Programming
Hard
5
0.5%
1719Maximum Odd Binary Number
Math, String, Greedy
Easy
5
0.8%
1720Length of Longest Subarray With at Most K Frequency
Array, Hash Table, Sliding Window
Medium
5
0.6%
1721Minimum Cost Walk in Weighted Graph
Array, Bit Manipulation, Union-Find, Graph Theory
Hard
5
0.7%
1722Minimum Cost to Equalize Array
Array, Greedy, Enumeration
Hard
5
0.2%
1723Special Array II
Array, Binary Search, Prefix Sum
Medium
5
0.5%
1724Special Array I
Array
Easy
5
0.8%
1725Find the Number of Good Pairs II
Array, Hash Table
Medium
5
0.3%
1726Valid Palindrome III
String, Dynamic Programming
Hard
5
0.5%
1727Make Two Arrays Equal by Reversing Subarrays
Array, Hash Table, Sorting
Easy
5
0.8%
1728Range Sum of Sorted Subarray Sums
Array, Two Pointers, Binary Search, Sorting, Prefix Sum
Medium
5
0.6%
1729Minimum Interval to Include Each Query
Array, Binary Search, Sweep Line, Sorting, Heap (Priority Queue)
Hard
5
0.5%
1730Reverse Nodes in Even Length Groups
Linked List
Medium
5
0.6%
1731Maximum Distance in Arrays
Array, Greedy
Medium
5
0.5%
1732Maximum Number of Points with Cost
Array, Dynamic Programming, Matrix
Medium
5
0.4%
1733Subarray With Elements Greater Than Varying Threshold
Array, Stack, Union-Find, Monotonic Stack
Hard
5
0.5%
1734Find Elements in a Contaminated Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree
Medium
5
0.8%
1735Lexicographically Smallest String After Substring Operation
String, Greedy
Medium
5
0.4%
1736Count Nodes With the Highest Score
Array, Tree, Depth-First Search, Binary Tree
Medium
5
0.5%
1737Two Sum III - Data structure design
Array, Hash Table, Two Pointers, Design, Data Stream
Easy
5
0.4%
1738Encrypt and Decrypt Strings
Array, Hash Table, String, Design, Trie
Hard
5
0.4%
1739Design Circular Deque
Array, Linked List, Design, Queue
Medium
5
0.6%
1740Sentence Similarity III
Array, Two Pointers, String
Medium
5
0.5%
1741Number of Changing Keys
String
Easy
5
0.8%
1742Minimum Insertions to Balance a Parentheses String
String, Stack, Greedy
Medium
5
0.5%
1743Word Pattern II
Hash Table, String, Backtracking
Medium
5
0.5%
1744Divide Intervals Into Minimum Number of Groups
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
5
0.6%
1745Random Pick with Blacklist
Array, Hash Table, Math, Binary Search, Sorting, Randomized
Hard
5
0.4%
1746Complete Binary Tree Inserter
Tree, Breadth-First Search, Design, Binary Tree
Medium
5
0.7%
1747Minimum Division Operations to Make Array Non Decreasing
Array, Math, Greedy, Number Theory
Medium
5
0.3%
1748The Most Recent Orders for Each Product
Database
Medium
5
0.7%
1749Find if Array Can Be Sorted
Array, Bit Manipulation, Sorting
Medium
5
0.7%
1750Simple Bank System
Array, Hash Table, Design, Simulation
Medium
5
0.7%
1751Prime Subtraction Operation
Array, Math, Binary Search, Greedy, Number Theory
Medium
5
0.6%
1752Final Array State After K Multiplication Operations I
Array, Math, Heap (Priority Queue), Simulation
Easy
5
0.9%
1753Length of the Longest Alphabetical Continuous Substring
String
Medium
5
0.6%
1754The Maze II
Array, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
5
0.6%
1755Valid Arrangement of Pairs
Array, Depth-First Search, Graph Theory, Eulerian Circuit
Hard
5
0.7%
1756Check If a Word Occurs As a Prefix of Any Word in a Sentence
Two Pointers, String, String Matching
Easy
5
0.7%
1757Find Longest Special Substring That Occurs Thrice I
Hash Table, String, Binary Search, Sliding Window, Counting
Medium
5
0.6%
1758Minimum Operations to Make Array Equal to Target
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Hard
5
0.4%
1759Maximum Number of K-Divisible Components
Tree, Depth-First Search
Hard
5
0.7%
1760Maximum Strength of K Disjoint Subarrays
Array, Dynamic Programming, Prefix Sum
Hard
5
0.3%
1761Count Collisions on a Road
String, Stack, Simulation
Medium
5
0.6%
1762Button with Longest Push Time
Array
Easy
5
0.4%
1763All People Report to the Given Manager
Database
Medium
5
0.8%
1764Largest Element in an Array after Merge Operations
Array, Greedy
Medium
5
0.5%
1765Minimum Length of String After Operations
Hash Table, String, Counting
Medium
5
0.8%
1766Maximum XOR After Operations
Array, Math, Bit Manipulation
Medium
5
0.8%
1767Maximum Possible Number by Binary Concatenation
Array, Bit Manipulation, Enumeration
Medium
5
0.7%
1768Maximize the Minimum Game Score
Array, Binary Search, Greedy
Hard
5
0.3%
1769Maximum Sum With Exactly K Elements
Array, Greedy
Easy
5
0.8%
1770Minimum Score of a Path Between Two Cities
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
5
0.6%
1771Range Addition
Array, Prefix Sum
Medium
5
0.7%
1772Check if Matrix Is X-Matrix
Array, Matrix
Easy
5
0.7%
1773Select K Disjoint Special Substrings
Hash Table, String, Dynamic Programming, Greedy, Sorting
Medium
5
0.2%
1774Find Common Elements Between Two Arrays
Array, Hash Table
Easy
5
0.8%
1775Count Days Without Meetings
Array, Sorting
Medium
5
0.5%
1776Minimum Index of a Valid Split
Array, Hash Table, Sorting
Medium
5
0.8%
1777Maximum Score of Non-overlapping Intervals
Array, Binary Search, Dynamic Programming, Sorting
Hard
5
0.3%
1778Remove Stones to Minimize the Total
Array, Greedy, Heap (Priority Queue)
Medium
5
0.7%
1779Maximum Value of an Ordered Triplet II
Array
Medium
5
0.6%
1780Customer Purchasing Behavior Analysis
Database
Medium
5
0.4%
1781Number of Subarrays That Match a Pattern I
Array, Rolling Hash, String Matching, Hash Function
Medium
5
0.7%
1782Describe the Painting
Array, Hash Table, Sorting, Prefix Sum
Medium
5
0.5%
1783String Without AAA or BBB
String, Greedy
Medium
5
0.5%
1784Zuma Game
String, Dynamic Programming, Stack, Breadth-First Search, Memoization
Hard
5
0.3%
1785Merge Two 2D Arrays by Summing Values
Array, Hash Table, Two Pointers
Easy
5
0.8%
1786Pizza Toppings Cost Analysis
Database
Medium
5
0.7%
1787Maximum Profit From Trading Stocks
Array, Dynamic Programming
Medium
5
0.5%
1788Minimum Number of Swaps to Make the Binary String Alternating
String, Greedy
Medium
5
0.4%
1789Minimum Amount of Damage Dealt to Bob
Array, Greedy, Sorting
Hard
5
0.4%
1790Painting a Grid With Three Different Colors
Dynamic Programming
Hard
5
0.8%
1791Manhattan Distances of All Arrangements of Pieces
Math, Combinatorics
Hard
5
0.4%
1792Minimum Cost to Make Arrays Identical
Array, Greedy, Sorting
Medium
5
0.4%
1793Integer Replacement
Dynamic Programming, Greedy, Bit Manipulation, Memoization
Medium
5
0.4%
1794Pizza With 3n Slices
Array, Dynamic Programming, Greedy, Heap (Priority Queue)
Hard
5
0.5%
1795Tiling a Rectangle with the Fewest Squares
Backtracking
Hard
5
0.6%
1796Count Beautiful Splits in an Array
Array, Dynamic Programming
Medium
5
0.2%
1797Binary Tree Longest Consecutive Sequence
Tree, Depth-First Search, Binary Tree
Medium
5
0.5%
1798Maximum Value of an Ordered Triplet I
Array
Easy
5
0.6%
1799Zero Array Transformation III
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
5
0.5%
1800Year on Year Growth Rate
Database
Hard
5
0.5%
1801Count the Number of Arrays with K Matching Adjacent Elements
Math, Combinatorics
Hard
5
0.6%
1802Number of Common Factors
Math, Enumeration, Number Theory
Easy
5
0.8%
1803Find Smallest Common Element in All Rows
Array, Hash Table, Binary Search, Matrix, Counting
Medium
5
0.8%
1804Delete Greatest Value in Each Row
Array, Sorting, Heap (Priority Queue), Matrix, Simulation
Easy
5
0.8%
1805Longest Subsequence Repeated k Times
Hash Table, Two Pointers, String, Backtracking, Counting, Enumeration
Hard
5
0.7%
1806Longest Common Prefix Between Adjacent Strings After Removals
Array, String
Medium
5
0.3%
1807Minimum Cost to Move Chips to The Same Position
Array, Math, Greedy
Easy
5
0.7%
1808Kth Smallest Instructions
Array, Math, Dynamic Programming, Combinatorics
Hard
5
0.4%
1809Maximum Beauty of an Array After Applying Operation
Array, Binary Search, Sliding Window, Sorting
Medium
5
0.6%
1810Find Special Substring of Length K
String
Easy
5
0.4%
1811Game Play Analysis II
Database
Easy
5
0.5%
1812Check Knight Tour Configuration
Array, Depth-First Search, Breadth-First Search, Matrix, Simulation
Medium
5
0.6%
1813Maximum Number of Visible Points
Array, Math, Geometry, Sliding Window, Sorting
Hard
5
0.4%
1814Minimize the Maximum Adjacent Element Difference
Array, Binary Search, Greedy
Hard
5
0.2%
1815Maximum Depth of N-ary Tree
Tree, Depth-First Search, Breadth-First Search
Easy
5
0.7%
1816Inorder Successor in BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
5
0.5%
1817Maximum Size of a Set After Removals
Array, Hash Table, Greedy
Medium
5
0.5%
1818Maximum Difference by Remapping a Digit
Math, Greedy
Easy
5
0.8%
1819Increasing Decreasing String
Hash Table, String, Counting
Easy
5
0.8%
1820Find Valid Pair of Adjacent Digits in String
Hash Table, String, Counting
Easy
5
0.6%
1821Find Lucky Integer in an Array
Array, Hash Table, Counting
Easy
5
0.8%
1822Collecting Chocolates
Array, Enumeration
Medium
5
0.4%
1823Falling Squares
Array, Segment Tree, Ordered Set
Hard
5
0.5%
1824Number of Ways to Form a Target String Given a Dictionary
Array, String, Dynamic Programming
Hard
5
0.6%
1825Remove Duplicates From an Unsorted Linked List
Hash Table, Linked List
Medium
5
0.8%
1826Alice and Bob Playing Flower Game
Math
Medium
5
0.6%
1827Balanced K-Factor Decomposition
Math, Backtracking, Number Theory
Medium
5
0.4%
1828Find the Largest Palindrome Divisible by K
Math, String, Dynamic Programming, Greedy, Number Theory
Hard
5
0.2%
1829Reshape Data: MeltEasy
5
0.9%
1830Sort the Students by Their Kth Score
Array, Sorting, Matrix
Medium
5
0.9%
1831Maximize Greatness of an Array
Array, Two Pointers, Greedy, Sorting
Medium
5
0.6%
1832Alternating Digit Sum
Math
Easy
5
0.7%
1833Water Bottles II
Math, Simulation
Medium
5
0.8%
1834Count Substrings That Can Be Rearranged to Contain a String I
Hash Table, String, Sliding Window
Medium
5
0.4%
1835Sort Items by Groups Respecting Dependencies
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
5
0.7%
1836Minimum Number of Chairs in a Waiting Room
String, Simulation
Easy
5
0.8%
1837Minimum Operations to Write the Letter Y on a Grid
Array, Hash Table, Matrix, Counting
Medium
5
0.6%
1838Count Number of Ways to Place Houses
Dynamic Programming
Medium
5
0.4%
1839Binary Tree Coloring Game
Tree, Depth-First Search, Binary Tree
Medium
5
0.5%
1840Two-Letter Card Game
Array, Hash Table, String, Counting, Enumeration
Medium
5
0.1%
1841Sequence Reconstruction
Array, Graph Theory, Topological Sort
Medium
5
0.3%
1842Maximum Value after Insertion
String, Greedy
Medium
5
0.4%
1843Delete Duplicate Folders in System
Array, Hash Table, String, Depth-First Search, Trie, Sorting, Hash Function
Hard
5
0.8%
1844Sum of Perfect Square Ancestors
Array, Hash Table, Math, Tree, Depth-First Search, Counting, Number Theory
Hard
5
0.4%
1845Consecutive Characters
String
Easy
5
0.6%
1846Non-decreasing Subsequences
Array, Hash Table, Backtracking, Bit Manipulation
Medium
5
0.6%
1847Stable Subarrays With Equal Boundary and Interior Sum
Array, Hash Table, Prefix Sum
Medium
5
0.3%
1848Count Unguarded Cells in the Grid
Array, Matrix, Simulation
Medium
5
0.7%
1849Smallest Palindromic Rearrangement I
String, Sorting, Counting Sort
Medium
5
0.6%
1850Wiggle Sort
Array, Greedy, Sorting
Medium
5
0.7%
1851Minimum Unique Word Abbreviation
Array, String, Backtracking, Bit Manipulation
Hard
5
0.4%
1852Minimum Time for K Connected Components
Binary Search, Union-Find, Graph Theory, Sorting
Medium
5
0.5%
1853Truncate Sentence
Array, String
Easy
5
0.9%
1854Minimum Operations to Make Array Equal
Math
Medium
5
0.8%
1855Count Partitions with Even Sum Difference
Array, Math, Prefix Sum
Easy
5
0.9%
1856Clumsy Factorial
Math, Stack, Simulation
Medium
5
0.6%
1857Shortest Distance After Road Addition Queries I
Array, Breadth-First Search, Graph Theory
Medium
5
0.6%
1858Count the Number of Computer Unlocking Permutations
Array, Math, Brainteaser, Combinatorics
Medium
5
0.6%
1859Find the Array Concatenation Value
Array, Two Pointers, Simulation
Easy
5
0.7%
1860Binary Prefix Divisible By 5
Array, Bit Manipulation
Easy
5
0.5%
1861Operations on Tree
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search, Design
Medium
5
0.5%
1862Maximize Cyclic Partition Score
Array, Dynamic Programming
Hard
5
0.1%
1863Implement Router
Array, Hash Table, Binary Search, Design, Queue, Ordered Set
Medium
5
0.4%
1864Range Addition II
Array, Math
Easy
5
0.6%
1865Delete Columns to Make Sorted III
Array, String, Dynamic Programming
Hard
5
0.7%
1866Four Divisors
Array, Math
Medium
5
0.6%
1867Lucky Numbers in a Matrix
Array, Matrix
Easy
5
0.8%
1868Sparse Matrix Multiplication
Array, Hash Table, Matrix
Medium
5
0.7%
1869Smallest Subtree with all the Deepest Nodes
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
5
0.8%
1870Restore the Array From Adjacent Pairs
Array, Hash Table, Depth-First Search
Medium
5
0.8%
1871Find Original Array From Doubled Array
Array, Hash Table, Greedy, Sorting
Medium
5
0.4%
1872Number of Substrings With Only 1s
Math, String
Medium
5
0.6%
1873Smallest Good Base
Math, Binary Search
Hard
5
0.5%
1874Promise Time LimitMedium
5
0.8%
1875Maximum Sum of Three Numbers Divisible by Three
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
5
0.5%
1876Non-decreasing Array
Array
Medium
5
0.3%
1877Implement Trie II (Prefix Tree)
Hash Table, String, Design, Trie
Medium
5
0.6%
1878Minimize the Maximum of Two Arrays
Math, Binary Search, Number Theory
Medium
5
0.3%
1879Minimum Value to Get Positive Step by Step Sum
Array, Prefix Sum
Easy
5
0.6%
1880Frog Jump II
Array, Binary Search, Greedy
Medium
5
0.6%
1881Design Spreadsheet
Array, Hash Table, String, Design, Matrix
Medium
5
0.7%
1882Array Nesting
Array, Depth-First Search
Medium
5
0.6%
1883Non-negative Integers without Consecutive Ones
Dynamic Programming
Hard
5
0.4%
1884Max Sum of Rectangle No Larger Than K
Array, Binary Search, Matrix, Prefix Sum, Ordered Set
Hard
5
0.5%
18853Sum With Multiplicity
Array, Hash Table, Two Pointers, Sorting, Counting
Medium
5
0.5%
1886Find Greatest Common Divisor of Array
Array, Math, Number Theory
Easy
5
0.8%
1887Vowels Game in a String
Math, String, Brainteaser, Game Theory
Medium
5
0.8%
1888Reachable Nodes In Subdivided Graph
Graph Theory, Heap (Priority Queue), Shortest Path
Hard
5
0.5%
1889Minimum Addition to Make Integer Beautiful
Math, Greedy
Medium
5
0.4%
1890Minimum Hours of Training to Win a Competition
Array, Greedy
Easy
5
0.4%
1891Ant on the Boundary
Array, Simulation, Prefix Sum
Easy
5
0.7%
1892Maximum Number of Points From Grid Queries
Array, Two Pointers, Breadth-First Search, Union-Find, Sorting, Heap (Priority Queue), Matrix
Hard
5
0.6%
1893Find Maximum Value in a Constrained Sequence
Array, Greedy
Medium
5
0.6%
1894Unique Morse Code Words
Array, Hash Table, String
Easy
5
0.8%
1895Longest Univalue Path
Tree, Depth-First Search, Binary Tree
Medium
5
0.4%
1896Minimum Seconds to Equalize a Circular Array
Array, Hash Table
Medium
5
0.3%
1897Number Complement
Bit Manipulation
Easy
5
0.7%
1898Longest Palindrome by Concatenating Two Letter Words
Array, Hash Table, String, Greedy, Counting
Medium
5
0.5%
1899Sort Vowels in a String
String, Sorting
Medium
5
0.8%
1900Split Strings by Separator
Array, String
Easy
5
0.8%
1901Special Positions in a Binary Matrix
Array, Matrix
Easy
5
0.7%
1902Tallest Billboard
Array, Dynamic Programming
Hard
5
0.5%
1903Word Abbreviation
Array, String, Greedy, Trie, Sorting
Hard
5
0.6%
1904Find Product Recommendation Pairs
Database
Medium
5
0.6%
1905Median Employee Salary
Database
Hard
5
0.7%
1906Minimum Changes To Make Alternating Binary String
String
Easy
5
0.7%
1907Missing Number In Arithmetic Progression
Array, Math
Easy
5
0.5%
1908Find All Possible Stable Binary Arrays I
Dynamic Programming, Prefix Sum
Medium
5
0.5%
1909Minimum Subarray Length With Distinct Sum At Least K
Array, Hash Table, Sliding Window
Medium
5
0.3%
1910Sum of Variable Length Subarrays
Array, Prefix Sum
Easy
5
0.9%
1911Maximum Number of Weeks for Which You Can Work
Array, Greedy
Medium
5
0.4%
1912Minimum Impossible OR
Array, Bit Manipulation, Brainteaser
Medium
5
0.6%
1913Minimum Absolute Difference in Sliding Submatrix
Array, Sorting, Matrix
Medium
5
0.8%
1914Grid Teleportation Traversal
Array, Hash Table, Breadth-First Search, Matrix
Medium
5
0.2%
1915Exam Room
Design, Heap (Priority Queue), Ordered Set
Medium
5
0.4%
1916Count Good Meals
Array, Hash Table
Medium
5
0.3%
1917Equal Sum Grid Partition I
Array, Matrix, Enumeration, Prefix Sum
Medium
5
0.5%
1918Count Submatrices With Equal Frequency of X and Y
Array, Matrix, Prefix Sum
Medium
5
0.7%
1919Design Movie Rental System
Array, Hash Table, Design, Heap (Priority Queue), Ordered Set
Hard
5
0.6%
1920Matrix Similarity After Cyclic Shifts
Array, Math, Matrix, Simulation
Easy
5
0.7%
1921Add Two PromisesEasy
5
0.9%
1922Check if Strings Can be Made Equal With Operations II
Hash Table, String, Sorting
Medium
5
0.7%
1923Lexicographically Smallest Generated String
String, Greedy, String Matching
Hard
5
0.5%
1924Stone Game
Array, Math, Dynamic Programming, Game Theory
Medium
5
0.7%
1925Final Element After Subarray Deletions
Array, Math, Brainteaser, Game Theory
Medium
5
0.4%
1926The Time When the Network Becomes Idle
Array, Breadth-First Search, Graph Theory
Medium
5
0.6%
1927Distribute Elements Into Two Arrays I
Array, Simulation
Easy
5
0.7%
1928Minimum Distance Between Three Equal Elements I
Array, Hash Table
Easy
5
0.7%
1929Minimum Distance Between Three Equal Elements II
Array, Hash Table
Medium
5
0.7%
1930Minimum Deletions to Make Array Divisible
Array, Math, Sorting, Heap (Priority Queue), Number Theory
Hard
5
0.6%
1931Properties Graph
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
5
0.5%
1932Final Array State After K Multiplication Operations II
Array, Heap (Priority Queue), Simulation
Hard
5
0.1%
1933Minimum Cost to Make Array Equal
Array, Binary Search, Greedy, Sorting, Prefix Sum
Hard
5
0.5%
1934Reverse Only Letters
Two Pointers, String
Easy
5
0.7%
1935Minimum Total Distance Traveled
Array, Dynamic Programming, Sorting
Hard
5
0.6%
1936Maximize the Confusion of an Exam
String, Binary Search, Sliding Window, Prefix Sum
Medium
5
0.7%
1937Largest Color Value in a Directed Graph
Hash Table, String, Dynamic Programming, Graph Theory, Topological Sort, Memoization, Counting
Hard
5
0.6%
1938Words Within Two Edits of Dictionary
Array, String, Trie
Medium
5
0.7%
1939Put Boxes Into the Warehouse I
Array, Greedy, Sorting
Medium
5
0.7%
1940Number of Subarrays With LCM Equal to K
Array, Math, Number Theory
Medium
5
0.5%
1941Minimum Cost to Split into Ones
Math, Dynamic Programming
Medium
5
0.8%
1942Jump Game VI
Array, Dynamic Programming, Queue, Heap (Priority Queue), Monotonic Queue
Medium
5
0.5%
1943Design Skiplist
Linked List, Design
Hard
5
0.6%
1944Cyclically Rotating a Grid
Array, Matrix, Simulation
Medium
5
0.7%
1945Minimum Cost to Buy Apples II
Array, Graph Theory, Heap (Priority Queue), Shortest Path
Hard
5
0.3%
1946Minimum Swaps to Group All 1's Together
Array, Sliding Window
Medium
5
0.6%
1947Pancake Sorting
Array, Two Pointers, Greedy, Sorting
Medium
5
0.7%
1948Smallest Index With Equal Value
Array
Easy
5
0.7%
1949Sum of Digits of String After Convert
String, Simulation
Easy
5
0.7%
1950Odd Even Jump
Array, Dynamic Programming, Stack, Sorting, Monotonic Stack, Ordered Set
Hard
5
0.4%
1951K-Similar Strings
Hash Table, String, Breadth-First Search
Hard
5
0.4%
1952Student Attendance Record I
String
Easy
5
0.5%
1953Find the Distinct Difference Array
Array, Hash Table
Easy
5
0.8%
1954Binary Trees With Factors
Array, Hash Table, Dynamic Programming, Sorting
Medium
5
0.5%
1955Score of Parentheses
String, Stack
Medium
5
0.6%
1956Maximum Total Subarray Value II
Array, Greedy, Segment Tree, Heap (Priority Queue)
Hard
5
0.4%
1957Employees Whose Manager Left the Company
Database
Easy
5
0.5%
1958Build an Array With Stack Operations
Array, Stack, Simulation
Medium
5
0.8%
1959Find Mirror Score of a String
Hash Table, String, Stack, Simulation
Medium
5
0.4%
1960Kth Smallest Number in Multiplication Table
Math, Binary Search
Hard
5
0.5%
1961Number of Ways to Assign Edge Weights II
Array, Math, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search
Hard
5
0.7%
1962Maximize Sum of Device RatingsMedium
5
0.4%
1963Find Minimum Cost to Remove Array Elements
Array, Dynamic Programming
Medium
5
0.2%
1964Maximum Building Height
Array, Math, Sorting
Hard
5
0.7%
1965Maximize Sum Of Array After K Negations
Array, Greedy, Sorting
Easy
5
0.5%
1966Number of Unique Good Subsequences
String, Dynamic Programming
Hard
5
0.5%
1967Number of ZigZag Arrays II
Math, Dynamic Programming
Hard
5
0.7%
1968Collect Coins in a Tree
Array, Tree, Graph Theory, Topological Sort
Hard
5
0.4%

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.