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Bloomberg LeetCode Questions

1200 questions all-time · 395 easy · 645 medium · 160 hard
# Problem Difficulty Frequency Acceptance
1Two Sum
Array, Hash Table
Easy
100
0.6%
2Merge Intervals
Array, Sorting
Medium
87
0.5%
3Add Two Numbers
Linked List, Math, Recursion
Medium
85
0.5%
4Longest Substring Without Repeating Characters
Hash Table, String, Sliding Window
Medium
85
0.4%
5Valid Parentheses
String, Stack
Easy
85
0.4%
6Insert Delete GetRandom O(1)
Array, Hash Table, Math, Design, Randomized
Medium
85
0.6%
7Number of Islands
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
84
0.6%
8Best Time to Buy and Sell Stock
Array, Dynamic Programming
Easy
84
0.6%
9Trapping Rain Water
Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
Hard
81
0.7%
10Longest Palindromic Substring
Two Pointers, String, Dynamic Programming
Medium
80
0.4%
113Sum
Array, Two Pointers, Sorting
Medium
79
0.4%
12Invalid Transactions
Array, Hash Table, String, Sorting
Medium
79
0.3%
13Longest Common Prefix
Array, String, Trie
Easy
79
0.5%
14Flatten a Multilevel Doubly Linked List
Linked List, Depth-First Search, Doubly-Linked List
Medium
79
0.6%
15Word Search
Array, String, Backtracking, Depth-First Search, Matrix
Medium
78
0.5%
16Median of Two Sorted Arrays
Array, Binary Search, Divide and Conquer
Hard
77
0.5%
17Majority Element
Array, Hash Table, Divide and Conquer, Sorting, Counting
Easy
76
0.7%
18Reverse Integer
Math
Medium
76
0.3%
19Container With Most Water
Array, Two Pointers, Greedy
Medium
76
0.6%
20Merge Sorted Array
Array, Two Pointers, Sorting
Easy
75
0.6%
21Decode String
String, Stack, Recursion
Medium
75
0.6%
22Valid Anagram
Hash Table, String, Sorting
Easy
75
0.7%
23Remove Duplicates from Sorted Array
Array, Two Pointers
Easy
73
0.6%
24Palindrome Number
Math
Easy
73
0.6%
25Merge Two Sorted Lists
Linked List, Recursion
Easy
72
0.7%
26Roman to Integer
Hash Table, Math, String
Easy
72
0.7%
27LRU Cache
Hash Table, Linked List, Design, Doubly-Linked List
Medium
72
0.5%
28Longest Consecutive Sequence
Array, Hash Table, Union-Find
Medium
72
0.5%
29Subarray Sum Equals K
Array, Hash Table, Prefix Sum
Medium
72
0.5%
30Design Underground System
Hash Table, String, Design
Medium
72
0.7%
31Search in Rotated Sorted Array
Array, Binary Search
Medium
71
0.5%
32Min Stack
Stack, Design
Medium
71
0.6%
33Maximum Subarray
Array, Divide and Conquer, Dynamic Programming
Medium
71
0.5%
34Group Anagrams
Array, Hash Table, String, Sorting
Medium
70
0.7%
35Subsets
Array, Backtracking, Bit Manipulation
Medium
70
0.8%
36Next Permutation
Array, Two Pointers
Medium
69
0.5%
37Move Zeroes
Array, Two Pointers
Easy
68
0.6%
38First Unique Character in a String
Hash Table, String, Queue, Counting
Easy
68
0.7%
39Rotate Image
Array, Math, Matrix
Medium
67
0.8%
40Generate Parentheses
String, Dynamic Programming, Backtracking
Medium
66
0.8%
41Climbing Stairs
Math, Dynamic Programming, Memoization
Easy
66
0.5%
42Rotate Array
Array, Math, Two Pointers
Medium
66
0.5%
43Validate Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
65
0.4%
44Find Peak Element
Array, Binary Search
Medium
65
0.5%
45Meeting Rooms II
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
65
0.5%
46Reverse Linked List
Linked List, Recursion
Easy
65
0.8%
47Number of Ships in a Rectangle
Array, Divide and Conquer, Interactive
Hard
65
0.7%
48Word Break II
Array, Hash Table, String, Dynamic Programming, Backtracking, Trie, Memoization
Hard
64
0.6%
49Create Hello World FunctionEasy
64
0.8%
50Valid Palindrome
Two Pointers, String
Easy
63
0.5%
51Koko Eating Bananas
Array, Binary Search
Medium
63
0.5%
52String to Integer (atoi)
String
Medium
63
0.2%
53Find First and Last Position of Element in Sorted Array
Array, Binary Search
Medium
63
0.5%
54Coin Change
Array, Dynamic Programming, Breadth-First Search
Medium
63
0.5%
55Sqrt(x)
Math, Binary Search
Easy
63
0.4%
56Pascal's Triangle
Array, Dynamic Programming
Easy
63
0.8%
57Single Number
Array, Bit Manipulation
Easy
63
0.8%
58Longest Repeating Character Replacement
Hash Table, String, Sliding Window
Medium
63
0.6%
594Sum
Array, Two Pointers, Sorting
Medium
62
0.4%
60Jump Game
Array, Dynamic Programming, Greedy
Medium
62
0.4%
61Contains Duplicate
Array, Hash Table, Sorting
Easy
62
0.6%
62Sort Integers by The Power Value
Dynamic Programming, Memoization, Sorting
Medium
62
0.7%
63Pow(x, n)
Math, Recursion
Medium
62
0.4%
64Sort Colors
Array, Two Pointers, Sorting
Medium
61
0.7%
65Remove Element
Array, Two Pointers
Easy
61
0.6%
66Single Element in a Sorted Array
Array, Binary Search
Medium
61
0.6%
67All Paths From Source to Target
Backtracking, Depth-First Search, Breadth-First Search, Graph Theory
Medium
61
0.8%
68Evaluate Division
Array, String, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Shortest Path
Medium
60
0.6%
69Check if Array Is Sorted and Rotated
Array
Easy
60
0.6%
70Plus One
Array, Math
Easy
60
0.5%
71Remove All Adjacent Duplicates in String II
String, Stack
Medium
60
0.6%
72Spiral Matrix
Array, Matrix, Simulation
Medium
59
0.6%
73Palindrome Partitioning
String, Dynamic Programming, Backtracking
Medium
59
0.7%
74Word Break
Array, Hash Table, String, Dynamic Programming, Trie, Memoization
Medium
59
0.5%
75House Robber
Array, Dynamic Programming
Medium
59
0.5%
76Product of Array Except Self
Array, Prefix Sum
Medium
59
0.7%
77Merge k Sorted Lists
Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort
Hard
58
0.6%
78Find the Index of the First Occurrence in a String
Two Pointers, String, String Matching
Easy
58
0.5%
79Binary Tree Level Order Traversal
Tree, Breadth-First Search, Binary Tree
Medium
58
0.7%
80Two City Scheduling
Array, Greedy, Sorting
Medium
58
0.7%
81Remove Letter To Equalize Frequency
Hash Table, String, Counting
Easy
58
0.2%
82Search Insert Position
Array, Binary Search
Easy
58
0.5%
83Design an Ordered Stream
Array, Hash Table, Design, Data Stream
Easy
58
0.8%
84Combine Two Tables
Database
Easy
57
0.8%
85Palindrome Linked List
Linked List, Two Pointers, Stack, Recursion
Easy
57
0.6%
86Binary Tree Vertical Order Traversal
Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
Medium
57
0.6%
87Max Consecutive Ones
Array
Easy
57
0.7%
88Minimum Remove to Make Valid Parentheses
String, Stack
Medium
57
0.7%
89Set Matrix Zeroes
Array, Hash Table, Matrix
Medium
57
0.6%
90Reverse Words in a String
Two Pointers, String
Medium
57
0.6%
91Next Greater Element I
Array, Hash Table, Stack, Monotonic Stack
Easy
57
0.8%
92Zigzag Conversion
String
Medium
56
0.5%
933Sum Closest
Array, Two Pointers, Sorting
Medium
56
0.5%
94Best Time to Buy and Sell Stock II
Array, Dynamic Programming, Greedy
Medium
55
0.7%
95Copy List with Random Pointer
Hash Table, Linked List
Medium
55
0.6%
96Linked List Cycle
Hash Table, Linked List, Two Pointers
Easy
55
0.5%
97Kth Largest Element in an Array
Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
Medium
55
0.7%
98Rotting Oranges
Array, Breadth-First Search, Matrix
Medium
55
0.6%
99Recyclable and Low Fat Products
Database
Easy
55
0.9%
100Unique Paths
Math, Dynamic Programming, Combinatorics
Medium
55
0.7%
101Search a 2D Matrix
Array, Binary Search, Matrix
Medium
55
0.5%
102Largest Rectangle in Histogram
Array, Stack, Monotonic Stack
Hard
55
0.5%
103Symmetric Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
55
0.6%
104Balanced Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
55
0.6%
105Isomorphic Strings
Hash Table, String
Easy
55
0.5%
106Daily Temperatures
Array, Stack, Monotonic Stack
Medium
55
0.7%
107Vertical Order Traversal of a Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
Hard
55
0.5%
108N-Queens
Array, Backtracking
Hard
54
0.8%
109Rotate List
Linked List, Two Pointers
Medium
54
0.4%
110Gas Station
Array, Greedy
Medium
54
0.5%
111Candy
Array, Greedy
Hard
54
0.5%
112Reorder List
Linked List, Two Pointers, Stack, Recursion
Medium
54
0.7%
113String Compression
Two Pointers, String
Medium
54
0.6%
114Number of Provinces
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
54
0.7%
115Valid Triangle Number
Array, Two Pointers, Binary Search, Greedy, Sorting
Medium
54
0.6%
116Binary Search
Array, Binary Search
Easy
54
0.6%
117Letter Combinations of a Phone Number
Hash Table, String, Backtracking
Medium
54
0.7%
118Valid Sudoku
Array, Hash Table, Matrix
Medium
54
0.6%
119Contains Duplicate II
Array, Hash Table, Sliding Window
Easy
54
0.5%
120Missing Number
Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting
Easy
54
0.7%
121Managers with at Least 5 Direct Reports
Database
Medium
54
0.5%
122Combination Sum
Array, Backtracking
Medium
53
0.8%
123Add Binary
Math, String, Bit Manipulation, Simulation
Easy
53
0.6%
124Construct Binary Tree from Preorder and Inorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
53
0.7%
125Count Unhappy Friends
Array, Simulation
Medium
53
0.6%
126Merge Strings Alternately
Two Pointers, String
Easy
53
0.8%
127Swap Nodes in Pairs
Linked List, Recursion
Medium
52
0.7%
128Length of Last Word
String
Easy
52
0.6%
129Same Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
52
0.7%
130Populating Next Right Pointers in Each Node
Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
52
0.7%
131Maximum Product Subarray
Array, Dynamic Programming
Medium
52
0.4%
132Find the Duplicate Number
Array, Two Pointers, Binary Search, Bit Manipulation
Medium
52
0.6%
133Longest Increasing Subsequence
Array, Binary Search, Dynamic Programming
Medium
52
0.6%
134Top K Frequent Elements
Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect
Medium
52
0.7%
135Intersection of Two Arrays
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
52
0.8%
136Add Two Numbers II
Linked List, Math, Stack
Medium
52
0.6%
137Design A Leaderboard
Hash Table, Design, Sorting
Medium
52
0.7%
138Frequency of the Most Frequent Element
Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
Medium
52
0.4%
139Word Ladder
Hash Table, String, Breadth-First Search
Hard
51
0.5%
140Reverse String
Two Pointers, String
Easy
51
0.8%
141Lexicographical Numbers
Depth-First Search, Trie
Medium
51
0.8%
142Number of Recent Calls
Design, Queue, Data Stream
Easy
51
0.8%
143Regular Expression Matching
String, Dynamic Programming, Recursion
Hard
51
0.3%
144Integer to Roman
Hash Table, Math, String
Medium
51
0.7%
145Remove Nth Node From End of List
Linked List, Two Pointers
Medium
51
0.5%
146Binary Tree Zigzag Level Order Traversal
Tree, Breadth-First Search, Binary Tree
Medium
51
0.6%
147Kth Smallest Element in a BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
51
0.8%
148Find the Winner of the Circular Game
Array, Math, Recursion, Queue, Simulation
Medium
51
0.8%
149Jump Game II
Array, Dynamic Programming, Greedy
Medium
50
0.4%
150Permutations
Array, Backtracking
Medium
50
0.8%
151Unique Paths II
Array, Dynamic Programming, Matrix
Medium
50
0.4%
152Edit Distance
String, Dynamic Programming
Medium
50
0.6%
153Minimum Size Subarray Sum
Array, Binary Search, Sliding Window, Prefix Sum
Medium
50
0.5%
154Sliding Window Maximum
Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
Hard
50
0.5%
155H-Index
Array, Sorting, Counting Sort
Medium
50
0.4%
156Next Greater Element II
Array, Stack, Monotonic Stack
Medium
50
0.7%
157Fibonacci Number
Math, Dynamic Programming, Recursion, Memoization
Easy
50
0.7%
158Remove Duplicates from Sorted List
Linked List
Easy
49
0.6%
159Populating Next Right Pointers in Each Node II
Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
49
0.6%
160Two Sum II - Input Array Is Sorted
Array, Two Pointers, Binary Search
Medium
49
0.7%
161Happy Number
Hash Table, Math, Two Pointers
Easy
49
0.6%
162Peak Index in a Mountain Array
Array, Binary Search
Medium
49
0.7%
163Capacity To Ship Packages Within D Days
Array, Binary Search
Medium
49
0.7%
164Design Browser History
Array, Linked List, Stack, Design, Doubly-Linked List, Data Stream
Medium
49
0.8%
165Wildcard Matching
String, Dynamic Programming, Greedy, Recursion
Hard
48
0.3%
166Implement Trie (Prefix Tree)
Hash Table, String, Design, Trie
Medium
48
0.7%
167Lowest Common Ancestor of a Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
48
0.7%
168Reverse Vowels of a String
Two Pointers, String
Easy
48
0.6%
169Rotate String
String, String Matching
Easy
48
0.7%
170Reverse Nodes in k-Group
Linked List, Recursion
Hard
47
0.7%
171Subsets II
Array, Backtracking, Bit Manipulation
Medium
47
0.6%
172Evaluate Reverse Polish Notation
Array, Math, Stack
Medium
47
0.6%
173Rising Temperature
Database
Easy
47
0.5%
174Lowest Common Ancestor of a Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
47
0.7%
175Odd Even Linked List
Linked List
Medium
47
0.6%
176Partition Equal Subset Sum
Array, Dynamic Programming
Medium
47
0.5%
177Maximum Nesting Depth of the Parentheses
String, Stack
Easy
47
0.8%
178Average Time of Process per Machine
Database
Easy
47
0.7%
179Intersection of Two Linked Lists
Hash Table, Linked List, Two Pointers
Easy
46
0.6%
180Delete Node in a Linked List
Linked List
Medium
46
0.8%
181Split Array Largest Sum
Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
Hard
46
0.6%
182Top K Frequent Words
Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting
Medium
46
0.6%
183Online Stock Span
Stack, Design, Monotonic Stack, Data Stream
Medium
46
0.7%
184Sort an Array
Array, Divide and Conquer, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort
Medium
46
0.6%
185Minimum Number of Steps to Make Two Strings Anagram
Hash Table, String, Counting
Medium
46
0.8%
186Sudoku Solver
Array, Hash Table, Backtracking, Matrix
Hard
45
0.7%
187Maximum Depth of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
45
0.8%
188Triangle
Array, Dynamic Programming
Medium
45
0.6%
189Factorial Trailing Zeroes
Math
Medium
45
0.5%
190Course Schedule
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
45
0.5%
191Majority Element II
Array, Hash Table, Sorting, Counting
Medium
45
0.6%
192Power of Two
Math, Bit Manipulation, Recursion
Easy
45
0.5%
193Serialize and Deserialize Binary Tree
String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree
Hard
45
0.6%
194Diameter of Binary Tree
Tree, Depth-First Search, Binary Tree
Easy
45
0.7%
195Big Countries
Database
Easy
45
0.7%
196Article Views I
Database
Easy
45
0.8%
197Second Highest Salary
Database
Medium
45
0.5%
198Find Missing and Repeated Values
Array, Hash Table, Math, Matrix
Easy
45
0.8%
199Divide Two Integers
Math, Bit Manipulation
Medium
44
0.2%
200Combination Sum II
Array, Backtracking
Medium
44
0.6%
201Search in Rotated Sorted Array II
Array, Binary Search
Medium
44
0.4%
202Binary Tree Maximum Path Sum
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
44
0.4%
203Reverse Pairs
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
44
0.3%
204Max Consecutive Ones III
Array, Binary Search, Sliding Window, Prefix Sum
Medium
44
0.7%
205Monthly Transactions I
Database
Medium
44
0.6%
206Fruit Into Baskets
Array, Hash Table, Sliding Window
Medium
44
0.5%
207Longest Valid Parentheses
String, Dynamic Programming, Stack
Hard
43
0.4%
208Remove Duplicates from Sorted Array II
Array, Two Pointers
Medium
43
0.6%
209Largest Number
Array, String, Greedy, Sorting
Medium
43
0.4%
210Employees Earning More Than Their Managers
Database
Easy
43
0.7%
211Remove Linked List Elements
Linked List, Recursion
Easy
43
0.5%
212Implement Queue using Stacks
Stack, Design, Queue
Easy
43
0.7%
213Maximum Average Subarray I
Array, Sliding Window
Easy
43
0.5%
214Implement Magic Dictionary
Hash Table, String, Depth-First Search, Design, Trie
Medium
43
0.6%
215Middle of the Linked List
Linked List, Two Pointers
Easy
43
0.8%
216Squares of a Sorted Array
Array, Two Pointers, Sorting
Easy
43
0.7%
217Minimum Number of Days to Make m Bouquets
Array, Binary Search
Medium
43
0.6%
218Students and Examinations
Database
Easy
43
0.6%
219Minimum Window Substring
Hash Table, String, Sliding Window
Hard
42
0.5%
220Surrounded Regions
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
42
0.5%
221Binary Tree Right Side View
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
42
0.7%
222Count Primes
Array, Math, Enumeration, Number Theory
Medium
42
0.4%
223Implement Stack using Queues
Stack, Design, Queue
Easy
42
0.7%
224Search a 2D Matrix II
Array, Binary Search, Divide and Conquer, Matrix
Medium
42
0.6%
225Add Digits
Math, Simulation, Number Theory
Easy
42
0.7%
226Sort Characters By Frequency
Hash Table, String, Sorting, Heap (Priority Queue), Bucket Sort, Counting
Medium
42
0.8%
227Next Greater Element III
Math, Two Pointers, String
Medium
42
0.4%
228Binary Subarrays With Sum
Array, Hash Table, Sliding Window, Prefix Sum
Medium
42
0.7%
229Minimum Absolute Difference
Array, Sorting
Easy
42
0.8%
230Average Selling Price
Database
Easy
42
0.4%
231Concatenation of Array
Array, Simulation
Easy
42
0.9%
232Rearrange Array Elements by Sign
Array, Two Pointers, Simulation
Medium
42
0.8%
233First Missing Positive
Array, Hash Table
Hard
40
0.4%
234Remove Duplicates from Sorted List II
Linked List, Two Pointers
Medium
40
0.5%
235Maximal Rectangle
Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
Hard
40
0.6%
236Binary Tree Inorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
40
0.8%
237Sort List
Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort
Medium
40
0.6%
238Course Schedule II
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
40
0.6%
239House Robber II
Array, Dynamic Programming
Medium
40
0.5%
240Remove K Digits
String, Stack, Greedy, Monotonic Stack
Medium
40
0.4%
241Arranging Coins
Math, Binary Search
Easy
40
0.5%
242Permutation in String
Hash Table, Two Pointers, String, Sliding Window
Medium
40
0.5%
243Kill Process
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
40
0.7%
244Asteroid Collision
Array, Stack, Simulation
Medium
40
0.5%
245Maximum Profit in Job Scheduling
Array, Binary Search, Dynamic Programming, Sorting
Hard
40
0.5%
246Sort Array by Increasing Frequency
Array, Hash Table, Sorting
Easy
40
0.8%
247Flatten Binary Tree to Linked List
Linked List, Stack, Tree, Depth-First Search, Binary Tree
Medium
40
0.7%
248Diagonal Traverse
Array, Matrix, Simulation
Medium
40
0.7%
249Path Sum II
Backtracking, Tree, Depth-First Search, Binary Tree
Medium
39
0.6%
250Linked List Cycle II
Hash Table, Linked List, Two Pointers
Medium
39
0.6%
251Perfect Squares
Math, Dynamic Programming, Breadth-First Search
Medium
39
0.6%
252Ransom Note
Hash Table, String, Counting
Easy
39
0.7%
253Fizz Buzz
Math, String, Simulation
Easy
39
0.8%
254Non-overlapping Intervals
Array, Dynamic Programming, Greedy, Sorting
Medium
39
0.6%
255Contiguous Array
Array, Hash Table, Prefix Sum
Medium
39
0.5%
256Best Time to Buy and Sell Stock with Transaction Fee
Array, Dynamic Programming, Greedy
Medium
39
0.7%
257Accounts Merge
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting
Medium
39
0.6%
258Sum of Subarray Minimums
Array, Dynamic Programming, Stack, Monotonic Stack
Medium
39
0.4%
259Shortest Path in Binary Matrix
Array, Breadth-First Search, Matrix
Medium
39
0.5%
260Kth Missing Positive Number
Array, Binary Search
Easy
39
0.6%
261Add Two Integers
Math
Easy
39
0.9%
262Number of Digit One
Math, Dynamic Programming, Recursion
Hard
39
0.4%
263Simplify Path
String, Stack
Medium
38
0.5%
264Single Number II
Array, Bit Manipulation
Medium
38
0.7%
265Basic Calculator
Math, String, Stack, Recursion
Hard
38
0.5%
266Find Median from Data Stream
Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream
Hard
38
0.5%
267Increasing Triplet Subsequence
Array, Greedy
Medium
38
0.4%
268Reverse String II
Two Pointers, String
Easy
38
0.5%
269Employee Bonus
Database
Easy
38
0.8%
270Trim a Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
38
0.7%
271Subarray Sums Divisible by K
Array, Hash Table, Prefix Sum
Medium
38
0.6%
272Cousins in Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
38
0.6%
273Immediate Food Delivery II
Database
Medium
38
0.6%
274Even Odd Tree
Tree, Breadth-First Search, Binary Tree
Medium
38
0.7%
275Shortest Palindrome
String, Rolling Hash, String Matching, Hash Function
Hard
38
0.4%
276Find All Anagrams in a String
Hash Table, String, Sliding Window
Medium
38
0.5%
277Maximum Sum of Distinct Subarrays With Length K
Array, Hash Table, Sliding Window
Medium
38
0.4%
278Reordered Power of 2
Hash Table, Math, Sorting, Counting, Enumeration
Medium
38
0.7%
279Count and Say
String
Medium
36
0.6%
280Reverse Linked List II
Linked List
Medium
36
0.5%
281Minimum Depth of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
36
0.5%
282Find Minimum in Rotated Sorted Array
Array, Binary Search
Medium
36
0.5%
283Consecutive Numbers
Database
Medium
36
0.5%
284First Bad Version
Binary Search, Interactive
Easy
36
0.5%
285Design Hit Counter
Array, Binary Search, Design, Queue, Data Stream
Medium
36
0.7%
286Is Subsequence
Two Pointers, String, Dynamic Programming
Easy
36
0.5%
287Assign Cookies
Array, Two Pointers, Greedy, Sorting
Easy
36
0.6%
288Target Sum
Array, Dynamic Programming, Backtracking
Medium
36
0.5%
289Shortest Path to Get Food
Array, Breadth-First Search, Matrix
Medium
36
0.6%
290Find Customer Referee
Database
Easy
36
0.7%
291Remove Outermost Parentheses
String, Stack
Easy
36
0.9%
292Find in Mountain Array
Array, Binary Search, Interactive
Hard
36
0.4%
293Queries Quality and Percentage
Database
Easy
36
0.5%
294Replace Employee ID With The Unique Identifier
Database
Easy
36
0.8%
295Dot Product of Two Sparse Vectors
Array, Hash Table, Two Pointers, Design
Medium
36
0.9%
296Count Good Numbers
Math, Recursion
Medium
36
0.6%
297Confirmation Rate
Database
Medium
36
0.6%
298Partition Array Into Two Arrays to Minimize Sum Difference
Array, Two Pointers, Binary Search, Dynamic Programming, Bit Manipulation, Sorting, Ordered Set, Bitmask
Hard
36
0.2%
299Product Price at a Given Date
Database
Medium
36
0.6%
300Maximum Swap
Math, Greedy
Medium
36
0.5%
301Substring with Concatenation of All Words
Hash Table, String, Sliding Window
Hard
34
0.3%
302Permutations II
Array, Backtracking, Sorting
Medium
34
0.6%
303Combinations
Backtracking
Medium
34
0.7%
304Partition List
Linked List, Two Pointers
Medium
34
0.6%
305Read N Characters Given read4 II - Call Multiple Times
Array, Simulation, Interactive
Hard
34
0.4%
306Customers Who Never Order
Database
Easy
34
0.7%
307Repeated DNA Sequences
Hash Table, String, Bit Manipulation, Sliding Window, Rolling Hash, Hash Function
Medium
34
0.5%
308Basic Calculator II
Math, String, Stack
Medium
34
0.5%
309Summary Ranges
Array
Easy
34
0.5%
310Palindrome Permutation
Hash Table, String, Bit Manipulation
Easy
34
0.7%
311Range Sum Query - Immutable
Array, Design, Prefix Sum
Easy
34
0.7%
312Sparse Matrix Multiplication
Array, Hash Table, Matrix
Medium
34
0.7%
313Find the Difference
Hash Table, String, Bit Manipulation, Sorting
Easy
34
0.6%
314Delete Node in a BST
Tree, Binary Search Tree, Binary Tree
Medium
34
0.5%
315Exchange Seats
Database
Medium
34
0.7%
316Maximum Width of Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
34
0.5%
317Valid Parenthesis String
String, Dynamic Programming, Stack, Greedy
Medium
34
0.4%
318Redundant Connection
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
34
0.7%
319Flood Fill
Array, Depth-First Search, Breadth-First Search, Matrix
Easy
34
0.7%
320Contain Virus
Array, Depth-First Search, Breadth-First Search, Matrix, Simulation
Hard
34
0.6%
321Lemonade Change
Array, Greedy
Easy
34
0.6%
322Boats to Save People
Array, Two Pointers, Greedy, Sorting
Medium
34
0.6%
323Path In Zigzag Labelled Binary Tree
Math, Tree, Binary Tree
Medium
34
0.8%
324Longest Common Subsequence
String, Dynamic Programming
Medium
34
0.6%
325Unique Number of Occurrences
Array, Hash Table
Easy
34
0.8%
326Allocate Mailboxes
Array, Math, Dynamic Programming, Sorting
Hard
34
0.6%
327Truncate Sentence
Array, String
Easy
34
0.9%
328Maximum Number of Accepted Invitations
Array, Depth-First Search, Graph Theory, Matrix
Medium
34
0.5%
329Check if All the Integers in a Range Are Covered
Array, Hash Table, Prefix Sum
Easy
34
0.5%
330Build Array from Permutation
Array, Simulation
Easy
34
0.9%
331Shortest Distance to Target String in a Circular Array
Array, String
Easy
34
0.7%
332Power of Three
Math, Recursion
Easy
34
0.5%
333Interleaving String
String, Dynamic Programming
Medium
34
0.4%
334Multiply Strings
Math, String, Simulation
Medium
32
0.4%
335Minimum Path Sum
Array, Dynamic Programming, Matrix
Medium
32
0.7%
336Invert Binary Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
32
0.8%
337Different Ways to Add Parentheses
Math, String, Dynamic Programming, Recursion, Memoization
Medium
32
0.7%
338Remove Duplicate Letters
String, Stack, Greedy, Monotonic Stack
Medium
32
0.5%
339Sum of Two Integers
Math, Bit Manipulation
Medium
32
0.6%
340132 Pattern
Array, Binary Search, Stack, Monotonic Stack, Ordered Set
Medium
32
0.3%
341Continuous Subarray Sum
Array, Hash Table, Math, Prefix Sum
Medium
32
0.3%
342Design Search Autocomplete System
String, Depth-First Search, Design, Trie, Sorting, Heap (Priority Queue), Data Stream
Hard
32
0.5%
343Set Mismatch
Array, Hash Table, Bit Manipulation, Sorting
Easy
32
0.4%
344Find Pivot Index
Array, Prefix Sum
Easy
32
0.6%
345Find Eventual Safe States
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
32
0.7%
346Sort Array By Parity
Array, Two Pointers, Sorting
Easy
32
0.8%
347Greatest Common Divisor of Strings
Math, String
Easy
32
0.5%
348Number of Substrings Containing All Three Characters
Hash Table, String, Sliding Window
Medium
32
0.7%
349Running Sum of 1d Array
Array, Prefix Sum
Easy
32
0.9%
350Find if Path Exists in Graph
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Easy
32
0.6%
351How Many Numbers Are Smaller Than the Current Number
Array, Hash Table, Sorting, Counting Sort
Easy
32
0.9%
352Subarrays with K Different Integers
Array, Hash Table, Sliding Window, Counting
Hard
32
0.7%
353Letter Tile Possibilities
Hash Table, String, Backtracking, Counting
Medium
32
0.8%
354Partition Array According to Given Pivot
Array, Two Pointers, Simulation
Medium
32
0.9%
355Permutation Sequence
Math, Recursion
Hard
32
0.5%
356Jewels and Stones
Hash Table, String
Easy
32
0.9%
357Duplicate Emails
Database
Easy
32
0.7%
358Insert Interval
Array
Medium
30
0.5%
359Nth Highest Salary
Database
Medium
30
0.4%
360Ugly Number
Math
Easy
30
0.4%
361Word Pattern
Hash Table, String
Easy
30
0.4%
362Largest Divisible Subset
Array, Math, Dynamic Programming, Sorting
Medium
30
0.5%
363Find All Numbers Disappeared in an Array
Array, Hash Table
Easy
30
0.6%
364Island Perimeter
Array, Depth-First Search, Breadth-First Search, Matrix
Easy
30
0.7%
365Can Place Flowers
Array, Greedy
Easy
30
0.3%
366Sum of Square Numbers
Math, Two Pointers, Binary Search
Medium
30
0.4%
367Palindromic Substrings
Two Pointers, String, Dynamic Programming
Medium
30
0.7%
368Subarray Product Less Than K
Array, Binary Search, Sliding Window, Prefix Sum
Medium
30
0.5%
369Reorganize String
Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
30
0.6%
370Complement of Base 10 Integer
Bit Manipulation
Easy
30
0.6%
371Shuffle the Array
Array
Easy
30
0.9%
372Number of Good Pairs
Array, Hash Table, Math, Counting
Easy
30
0.9%
373Customer Who Visited but Did Not Make Any Transactions
Database
Easy
30
0.7%
374Number of Students Unable to Eat Lunch
Array, Stack, Queue, Simulation
Easy
30
0.8%
375Product Sales Analysis III
Database
Medium
30
0.5%
376Maximum Width Ramp
Array, Two Pointers, Stack, Monotonic Stack
Medium
30
0.6%
377Friend Requests II: Who Has the Most Friends
Database
Medium
30
0.6%
378Find Numbers with Even Number of Digits
Array, Math
Easy
30
0.8%
379Heaters
Array, Two Pointers, Binary Search, Sorting
Medium
30
0.4%
380Serialize and Deserialize N-ary Tree
String, Tree, Depth-First Search, Breadth-First Search
Hard
30
0.7%
381Longest Strictly Increasing or Strictly Decreasing Subarray
Array
Easy
30
0.6%
382Restaurant Growth
Database
Medium
30
0.6%
383Text Justification
Array, String, Simulation
Hard
28
0.5%
384Recover Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
28
0.6%
385Path Sum
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
28
0.6%
386Word Ladder II
Hash Table, String, Backtracking, Breadth-First Search
Hard
28
0.3%
387Clone Graph
Hash Table, Depth-First Search, Breadth-First Search, Graph Theory
Medium
28
0.7%
388Excel Sheet Column Title
Math, String
Easy
28
0.5%
389Single Number III
Array, Bit Manipulation
Medium
28
0.7%
390Count of Smaller Numbers After Self
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
28
0.4%
391Guess Number Higher or Lower
Binary Search, Interactive
Easy
28
0.6%
392Elimination Game
Math, Recursion
Medium
28
0.5%
393Third Maximum Number
Array, Sorting
Easy
28
0.4%
394Find All Duplicates in an Array
Array, Hash Table, Sorting
Medium
28
0.8%
39501 Matrix
Array, Dynamic Programming, Breadth-First Search, Matrix
Medium
28
0.5%
396Find K Closest Elements
Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue)
Medium
28
0.5%
397Max Area of Island
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
28
0.7%
398Candy Crush
Array, Two Pointers, Matrix, Simulation
Medium
28
0.8%
399Making A Large Island
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Hard
28
0.6%
400Minimum Add to Make Parentheses Valid
String, Stack, Greedy
Medium
28
0.7%
401Remove All Adjacent Duplicates In String
String, Stack
Easy
28
0.7%
402Reverse Substrings Between Each Pair of Parentheses
String, Stack
Medium
28
0.7%
403The Number of Employees Which Report to Each Employee
Database
Easy
28
0.5%
404Check if the Sentence Is Pangram
Hash Table, String
Easy
28
0.8%
405Largest Odd Number in String
Math, String, Greedy
Easy
28
0.7%
406CounterEasy
28
0.8%
407Insert Delete GetRandom O(1) - Duplicates allowed
Array, Hash Table, Math, Design, Randomized
Hard
28
0.4%
408Delete Duplicate Emails
Database
Easy
28
0.7%
409Primary Department for Each Employee
Database
Easy
28
0.7%
410Tuple with Same Product
Array, Hash Table, Counting
Medium
28
0.7%
411Max Sum of a Pair With Equal Sum of Digits
Array, Hash Table, Sorting, Heap (Priority Queue)
Medium
28
0.7%
412Finding 3-Digit Even Numbers
Array, Hash Table, Recursion, Sorting, Enumeration
Easy
28
0.8%
413Rank Scores
Database
Medium
28
0.7%
414Perfect Number
Math
Easy
28
0.5%
415N-Queens II
Backtracking
Hard
25
0.8%
416Decode Ways
String, Dynamic Programming
Medium
25
0.4%
417Distinct Subsequences
String, Dynamic Programming
Hard
25
0.5%
418Best Time to Buy and Sell Stock III
Array, Dynamic Programming
Hard
25
0.5%
419Binary Tree Preorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
25
0.8%
420Binary Search Tree Iterator
Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator
Medium
25
0.8%
421Ugly Number II
Hash Table, Math, Dynamic Programming, Heap (Priority Queue)
Medium
25
0.5%
422Reconstruct Itinerary
Array, String, Depth-First Search, Graph Theory, Sorting, Heap (Priority Queue), Eulerian Circuit
Hard
25
0.4%
423Valid Perfect Square
Math, Binary Search
Easy
25
0.5%
424Longest Palindrome
Hash Table, String, Greedy
Easy
25
0.6%
425Repeated Substring Pattern
String, String Matching
Easy
25
0.5%
426Coin Change II
Array, Dynamic Programming
Medium
25
0.6%
427Array Partition
Array, Greedy, Sorting, Counting Sort
Easy
25
0.8%
428Not Boring Movies
Database
Easy
25
0.8%
429Task Scheduler
Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting
Medium
25
0.6%
430Maximum Product of Three Numbers
Array, Math, Sorting
Easy
25
0.5%
431Valid Palindrome II
Two Pointers, String, Greedy
Easy
25
0.4%
432Cheapest Flights Within K Stops
Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
25
0.4%
433Time Based Key-Value Store
Hash Table, String, Binary Search, Design
Medium
25
0.5%
434Defanging an IP Address
String
Easy
25
0.9%
435Critical Connections in a Network
Depth-First Search, Graph Theory, Biconnected Component
Hard
25
0.6%
436Last Person to Fit in the Bus
Database
Medium
25
0.7%
437Check If N and Its Double Exist
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
25
0.4%
438Kids With the Greatest Number of Candies
Array
Easy
25
0.9%
439Number of Subsequences That Satisfy the Given Sum Condition
Array, Two Pointers, Binary Search, Sorting
Medium
25
0.5%
440House Robber IV
Array, Binary Search, Dynamic Programming, Greedy
Medium
25
0.6%
441Create a DataFrame from ListEasy
25
0.8%
442Score of a String
String
Easy
25
0.9%
443Employees Whose Manager Left the Company
Database
Easy
25
0.5%
444Find K-th Smallest Pair Distance
Array, Two Pointers, Binary Search, Sorting
Hard
25
0.5%
445Remove All Occurrences of a Substring
String, Stack, Simulation
Medium
25
0.8%
446Movie Rating
Database
Medium
25
0.4%
447Array Prototype LastEasy
25
0.7%
448Most Stones Removed with Same Row or Column
Hash Table, Depth-First Search, Union-Find, Graph Theory
Medium
25
0.6%
449Add to Array-Form of Integer
Array, Math
Easy
25
0.5%
450Find Closest Number to Zero
Array
Easy
25
0.5%
451Rank Transform of an Array
Array, Hash Table, Sorting
Easy
25
0.7%
452Couples Holding Hands
Greedy, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Hard
25
0.6%
453Reverse Bits
Divide and Conquer, Bit Manipulation
Easy
25
0.7%
454Minimum Limit of Balls in a Bag
Array, Binary Search
Medium
25
0.7%
455Defuse the Bomb
Array, Sliding Window
Easy
25
0.8%
456Two Sum IV - Input is a BST
Hash Table, Two Pointers, Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
Easy
25
0.6%
457Check if All Characters Have Equal Number of Occurrences
Hash Table, String, Counting
Easy
25
0.8%
458Best Sightseeing Pair
Array, Dynamic Programming
Medium
25
0.6%
459Count the Number of Arrays with K Matching Adjacent Elements
Math, Combinatorics
Hard
25
0.6%
460Unique Length-3 Palindromic Subsequences
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
25
0.7%
461Clear Digits
String, Stack, Simulation
Easy
25
0.8%
462Find the Punishment Number of an Integer
Math, Backtracking
Medium
25
0.8%
463User Activity for the Past 30 Days I
Database
Easy
25
0.5%
464Rabbits in Forest
Array, Hash Table, Math, Greedy
Medium
25
0.6%
465Angle Between Hands of a Clock
Math
Medium
25
0.7%
466Kth Smallest Product of Two Sorted Arrays
Array, Binary Search
Hard
25
0.5%
467Maximum Number of Events That Can Be Attended
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
25
0.4%
468Valid Word
String
Easy
25
0.5%
469Find Winner on a Tic Tac Toe Game
Array, Hash Table, Matrix, Simulation
Easy
25
0.5%
470Trips and Users
Database
Hard
25
0.4%
471Next Greater Numerically Balanced Number
Hash Table, Math, Backtracking, Counting, Enumeration
Medium
25
0.6%
472Bus Routes
Array, Hash Table, Breadth-First Search
Hard
25
0.5%
473Can Make Arithmetic Progression From Sequence
Array, Sorting
Easy
25
0.7%
474Count Binary Substrings
Two Pointers, String
Easy
25
0.7%
475Sum of Root To Leaf Binary Numbers
Tree, Depth-First Search, Binary Tree
Easy
25
0.8%
476Convert Sorted Array to Binary Search Tree
Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
Easy
22
0.8%
477Sum Root to Leaf Numbers
Tree, Depth-First Search, Binary Tree
Medium
22
0.7%
478Binary Tree Postorder Traversal
Stack, Tree, Depth-First Search, Binary Tree
Easy
22
0.8%
479Department Top Three Salaries
Database
Hard
22
0.6%
480Design Add and Search Words Data Structure
String, Depth-First Search, Design, Trie
Medium
22
0.5%
481Count Complete Tree Nodes
Binary Search, Bit Manipulation, Tree, Binary Tree
Easy
22
0.7%
482Integer to English Words
Math, String, Recursion
Hard
22
0.4%
483Range Sum Query 2D - Mutable
Array, Design, Binary Indexed Tree, Segment Tree, Matrix
Medium
22
0.5%
484Counting Bits
Dynamic Programming, Bit Manipulation
Easy
22
0.8%
485Intersection of Two Arrays II
Array, Hash Table, Two Pointers, Binary Search, Sorting
Easy
22
0.6%
486Convert a Number to Hexadecimal
Math, String, Bit Manipulation
Easy
22
0.5%
487IPO
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
22
0.5%
488Relative Ranks
Array, Sorting, Heap (Priority Queue)
Easy
22
0.7%
489Find Largest Value in Each Tree Row
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
22
0.7%
490Minimum Time Difference
Array, Math, String, Sorting
Medium
22
0.6%
491Triangle Judgement
Database
Easy
22
0.7%
492Min Cost Climbing Stairs
Array, Dynamic Programming
Easy
22
0.7%
493Car Fleet
Array, Stack, Sorting, Monotonic Stack
Medium
22
0.6%
494Transpose Matrix
Array, Matrix, Simulation
Easy
22
0.8%
495Snakes and Ladders
Array, Breadth-First Search, Matrix
Medium
22
0.5%
496Number of Enclaves
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
22
0.7%
497Count Number of Nice Subarrays
Array, Hash Table, Math, Sliding Window, Prefix Sum
Medium
22
0.8%
498Find the Smallest Divisor Given a Threshold
Array, Binary Search
Medium
22
0.7%
499Count Negative Numbers in a Sorted Matrix
Array, Binary Search, Matrix
Easy
22
0.8%
500Minimum Cost to Cut a Stick
Array, Dynamic Programming, Sorting
Hard
22
0.6%
501Max Number of K-Sum Pairs
Array, Hash Table, Two Pointers, Sorting
Medium
22
0.6%
502Find the Highest Altitude
Array, Prefix Sum
Easy
22
0.8%
503Find a Peak Element II
Array, Binary Search, Matrix
Medium
22
0.6%
504Find the Maximum Achievable Number
Math
Easy
22
0.9%
505Find N Unique Integers Sum up to Zero
Array, Math
Easy
22
0.8%
506Sum of Subarray Ranges
Array, Stack, Monotonic Stack
Medium
22
0.6%
507Game Play Analysis IV
Database
Medium
22
0.4%
508Customers Who Bought All Products
Database
Medium
22
0.6%
509Smallest Range Covering Elements from K Lists
Array, Hash Table, Greedy, Sliding Window, Sorting, Heap (Priority Queue)
Hard
22
0.7%
510Invalid Tweets
Database
Easy
22
0.9%
511Longest Harmonious Subsequence
Array, Hash Table, Sliding Window, Sorting, Counting
Easy
22
0.6%
512Maximum Points You Can Obtain from Cards
Array, Sliding Window, Prefix Sum
Medium
22
0.6%
513Car Pooling
Array, Sorting, Heap (Priority Queue), Simulation, Prefix Sum
Medium
22
0.6%
514Count the Number of Fair Pairs
Array, Two Pointers, Binary Search, Sorting
Medium
22
0.5%
515Shortest Subarray to be Removed to Make Array Sorted
Array, Two Pointers, Binary Search, Stack, Monotonic Stack
Medium
22
0.5%
516Expression Add Operators
Math, String, Backtracking
Hard
22
0.4%
517Maximum Subarray Sum With Length Divisible by K
Array, Hash Table, Prefix Sum
Medium
22
0.5%
518Filter Elements from ArrayEasy
22
0.9%
519Minimum Number of Operations to Move All Balls to Each Box
Array, String, Prefix Sum
Medium
22
0.9%
520Minimum Cost For Tickets
Array, Dynamic Programming
Medium
22
0.7%
521Find the Prefix Common Array of Two Arrays
Array, Hash Table, Bit Manipulation
Medium
22
0.9%
522Next Greater Node In Linked List
Array, Linked List, Stack, Monotonic Stack
Medium
22
0.6%
523Sum of Beauty of All Substrings
Hash Table, String, Counting
Medium
22
0.7%
524The k-th Lexicographical String of All Happy Strings of Length n
String, Backtracking
Medium
22
0.9%
525Valid Number
String
Hard
22
0.2%
526Backspace String Compare
Two Pointers, String, Stack, Simulation
Easy
22
0.5%
527Maximum Candies Allocated to K Children
Array, Binary Search
Medium
22
0.5%
528Minimum Cost to Move Chips to The Same Position
Array, Math, Greedy
Easy
22
0.7%
529Longest Nice Subarray
Array, Bit Manipulation, Sliding Window
Medium
22
0.6%
530Minimum Number of Refueling Stops
Array, Dynamic Programming, Greedy, Heap (Priority Queue)
Hard
22
0.4%
531Detect Capital
String
Easy
22
0.6%
532Find Root of N-Ary Tree
Hash Table, Bit Manipulation, Tree, Depth-First Search
Medium
22
0.8%
533Count Symmetric Integers
Math, Enumeration
Easy
22
0.8%
534All Nodes Distance K in Binary Tree
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
22
0.7%
535Count the Hidden Sequences
Array, Prefix Sum
Medium
22
0.6%
536Find the K-th Character in String Game I
Math, Bit Manipulation, Recursion, Simulation
Easy
22
0.8%
537Push Dominoes
Two Pointers, String, Dynamic Programming
Medium
22
0.6%
538Longest Palindromic Subsequence
String, Dynamic Programming
Medium
22
0.7%
539Type of Triangle
Array, Math, Sorting
Easy
22
0.4%
540Zero Array Transformation I
Array, Prefix Sum
Medium
22
0.5%
541Find All K-Distant Indices in an Array
Array, Two Pointers
Easy
22
0.8%
542Number of Matching Subsequences
Array, Hash Table, String, Binary Search, Dynamic Programming, Trie, Sorting
Medium
22
0.5%
543Longest Binary Subsequence Less Than or Equal to K
String, Dynamic Programming, Greedy, Memoization
Medium
22
0.5%
544Find Subsequence of Length K With the Largest Sum
Array, Hash Table, Sorting, Heap (Priority Queue)
Easy
22
0.6%
545K Closest Points to Origin
Array, Math, Divide and Conquer, Geometry, Sorting, Heap (Priority Queue), Quickselect
Medium
22
0.7%
546Consecutive Characters
String
Easy
22
0.6%
547Bitwise ORs of Subarrays
Array, Dynamic Programming, Bit Manipulation
Medium
22
0.6%
548Ways to Express an Integer as Sum of Powers
Dynamic Programming
Medium
22
0.5%
549Robot Return to Origin
String, Simulation
Easy
22
0.8%
550Count Submatrices With All Ones
Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
Medium
22
0.7%
551Best Time to Buy and Sell Stock with Cooldown
Array, Dynamic Programming
Medium
22
0.6%
552Find the Minimum Area to Cover All Ones I
Array, Matrix
Medium
22
0.8%
553Subtree of Another Tree
Tree, Depth-First Search, String Matching, Binary Tree, Hash Function
Easy
22
0.5%
554Largest Triangle Area
Array, Math, Geometry
Easy
22
0.7%
555Minimum Time Visiting All Points
Array, Math, Geometry
Easy
22
0.8%
556Longest Balanced Subarray I
Array, Hash Table, Divide and Conquer, Segment Tree, Prefix Sum
Medium
22
0.7%
557Delete Nodes From Linked List Present in Array
Array, Hash Table, Linked List
Medium
22
0.7%
558Baseball Game
Array, Stack, Simulation
Easy
22
0.8%
559Divide an Array Into Subarrays With Minimum Cost I
Array, Sorting, Enumeration
Easy
22
0.8%
560Furthest Point From Origin
String, Counting
Easy
22
0.8%
561Pascal's Triangle II
Array, Dynamic Programming
Easy
18
0.7%
562Max Points on a Line
Array, Hash Table, Math, Geometry
Hard
18
0.3%
563Number of 1 Bits
Divide and Conquer, Bit Manipulation
Easy
18
0.8%
564Range Sum Query 2D - Immutable
Array, Design, Matrix, Prefix Sum
Medium
18
0.6%
565Burst Balloons
Array, Dynamic Programming
Hard
18
0.6%
566Integer Break
Math, Dynamic Programming
Medium
18
0.6%
567All O`one Data Structure
Hash Table, Linked List, Design, Doubly-Linked List
Hard
18
0.4%
568Minimum Genetic Mutation
Hash Table, String, Breadth-First Search
Medium
18
0.6%
569Minimum Number of Arrows to Burst Balloons
Array, Greedy, Sorting
Medium
18
0.6%
570Find Bottom Left Tree Value
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
18
0.7%
571Sales Person
Database
Easy
18
0.7%
572Maximum Length of Repeated Subarray
Array, Binary Search, Dynamic Programming, Sliding Window, Rolling Hash, Hash Function
Medium
18
0.5%
573Delete and Earn
Array, Hash Table, Dynamic Programming
Medium
18
0.6%
574Network Delay Time
Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path
Medium
18
0.6%
575Find Smallest Letter Greater Than Target
Array, Binary Search
Easy
18
0.6%
576Partition Labels
Hash Table, Two Pointers, String, Greedy
Medium
18
0.8%
577Hand of Straights
Array, Hash Table, Greedy, Sorting
Medium
18
0.6%
578Spiral Matrix III
Array, Matrix, Simulation
Medium
18
0.8%
579Find the Town Judge
Array, Hash Table, Graph Theory
Easy
18
0.5%
580Find Common Characters
Array, Hash Table, String
Easy
18
0.7%
581Construct Binary Search Tree from Preorder Traversal
Array, Stack, Tree, Binary Search Tree, Monotonic Stack, Binary Tree
Medium
18
0.8%
582Partition Array for Maximum Sum
Array, Dynamic Programming
Medium
18
0.8%
583Longest String Chain
Array, Hash Table, Two Pointers, String, Dynamic Programming, Sorting
Medium
18
0.6%
584Project Employees I
Database
Easy
18
0.7%
585N-th Tribonacci Number
Math, Dynamic Programming, Memoization
Easy
18
0.6%
586Balance a Binary Search Tree
Divide and Conquer, Greedy, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Medium
18
0.9%
587Find Users With Valid E-Mails
Database
Easy
18
0.4%
588Special Array With X Elements Greater Than or Equal X
Array, Binary Search, Sorting
Easy
18
0.7%
589Minimum Deletions to Make String Balanced
String, Dynamic Programming, Stack
Medium
18
0.7%
590Richest Customer Wealth
Array, Matrix
Easy
18
0.9%
591Delete the Middle Node of a Linked List
Linked List, Two Pointers
Medium
18
0.6%
592Maximum Twin Sum of a Linked List
Linked List, Two Pointers, Stack
Medium
18
0.8%
593Left and Right Sum Differences
Array, Prefix Sum
Easy
18
0.9%
594To Be Or Not To BeEasy
18
0.6%
595Return Length of Arguments PassedEasy
18
0.9%
596Find Common Elements Between Two Arrays
Array, Hash Table
Easy
18
0.8%
597Final Value of Variable After Performing Operations
Array, String, Simulation
Easy
18
0.9%
598Range Sum of Sorted Subarray Sums
Array, Two Pointers, Binary Search, Sorting, Prefix Sum
Medium
18
0.6%
599Guess the Word
Array, Math, String, Interactive, Game Theory
Hard
18
0.4%
600Strange Printer
String, Dynamic Programming
Hard
18
0.6%
601Meeting Rooms
Array, Sorting
Easy
18
0.6%
602Trapping Rain Water II
Array, Breadth-First Search, Heap (Priority Queue), Matrix
Hard
18
0.6%
603Minimum Bit Flips to Convert Number
Bit Manipulation
Easy
18
0.9%
604Find the Longest Substring Containing Vowels in Even Counts
Hash Table, String, Bit Manipulation, Prefix Sum
Medium
18
0.8%
605Search Suggestions System
Array, String, Binary Search, Trie, Sorting, Heap (Priority Queue)
Medium
18
0.7%
606Count Servers that Communicate
Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix, Counting
Medium
18
0.7%
607Number of Ways to Arrive at Destination
Dynamic Programming, Graph Theory, Topological Sort, Shortest Path
Medium
18
0.4%
608Design a Todo List
Array, Hash Table, String, Design, Sorting
Medium
18
0.6%
609Create Maximum Number
Array, Two Pointers, Stack, Greedy, Monotonic Stack
Hard
18
0.4%
610Minimum Total Distance Traveled
Array, Dynamic Programming, Sorting
Hard
18
0.6%
611Combination Sum III
Array, Backtracking
Medium
18
0.7%
612Add Strings
Math, String, Simulation
Easy
18
0.5%
613Open the Lock
Array, Hash Table, String, Breadth-First Search
Medium
18
0.6%
614Excel Sheet Column Number
Math, String
Easy
18
0.7%
615Continuous Subarrays
Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Medium
18
0.6%
616Game of Life
Array, Matrix, Simulation
Medium
18
0.7%
617Max Chunks To Make Sorted
Array, Stack, Greedy, Sorting, Monotonic Stack
Medium
18
0.6%
618Product Sales Analysis I
Database
Easy
18
0.9%
619Maximum Sum of 3 Non-Overlapping Subarrays
Array, Dynamic Programming, Sliding Window, Prefix Sum
Hard
18
0.6%
620Random Pick with Weight
Array, Math, Binary Search, Prefix Sum, Randomized
Medium
18
0.5%
621String Matching in an Array
Array, String, String Matching
Easy
18
0.7%
622Swap Sex of Employees
Database
Easy
18
0.8%
623Maximum Score Words Formed by Letters
Array, Hash Table, String, Dynamic Programming, Backtracking, Bit Manipulation, Counting, Bitmask
Hard
18
0.8%
624Restore IP Addresses
String, Backtracking
Medium
18
0.6%
625Shortest Distance from All Buildings
Array, Breadth-First Search, Matrix
Hard
18
0.4%
626Remove Zero Sum Consecutive Nodes from Linked List
Hash Table, Linked List
Medium
18
0.5%
627Find the Number of Distinct Colors Among the Balls
Array, Hash Table, Simulation
Medium
18
0.5%
628Count Salary Categories
Database
Medium
18
0.6%
629Distribute Candies
Array, Hash Table
Easy
18
0.7%
630Check if Number is a Sum of Powers of Three
Math
Medium
18
0.8%
631Maximum Number of Vowels in a Substring of Given Length
String, Sliding Window
Medium
18
0.6%
632Zero Array Transformation II
Array, Two Pointers, Binary Search, Prefix Sum
Medium
18
0.4%
633Divide Array Into Equal Pairs
Array, Hash Table, Bit Manipulation, Counting
Easy
18
0.8%
634Maximum Population Year
Array, Counting, Prefix Sum
Easy
18
0.6%
635Check if Grid can be Cut into Sections
Array, Sorting
Medium
18
0.7%
636Maximum Value of an Ordered Triplet II
Array
Medium
18
0.6%
637Minimum Number of Operations to Make Elements in Array Distinct
Array, Hash Table
Easy
18
0.7%
638Count Subarrays Where Max Element Appears at Least K Times
Array, Sliding Window
Medium
18
0.6%
639Zero Array Transformation III
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
18
0.5%
640Count the Number of Consistent Strings
Array, Hash Table, String, Bit Manipulation, Counting
Easy
18
0.9%
641Biggest Single Number
Database
Easy
18
0.7%
642Make The String Great
String, Stack
Easy
18
0.7%
643Apply Operations to an Array
Array, Two Pointers, Simulation
Easy
18
0.7%
644Row With Maximum Ones
Array, Matrix
Easy
18
0.7%
645Path With Minimum Effort
Array, Binary Search, Depth-First Search, Breadth-First Search, Union-Find, Heap (Priority Queue), Matrix
Medium
18
0.6%
646Maximum Manhattan Distance After K Changes
Hash Table, Math, String, Counting
Medium
18
0.5%
647Taking Maximum Energy From the Mystic Dungeon
Array, Dynamic Programming, Prefix Sum
Medium
18
0.6%
648Investments in 2016
Database
Medium
18
0.5%
649Maximum Number of Events That Can Be Attended II
Array, Binary Search, Dynamic Programming, Sorting
Hard
18
0.6%
650Binary Tree Cameras
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Hard
18
0.5%
651Find the Maximum Length of Valid Subsequence II
Array, Dynamic Programming
Medium
18
0.6%
652Successful Pairs of Spells and Potions
Array, Two Pointers, Binary Search, Sorting
Medium
18
0.5%
653Count Hills and Valleys in an Array
Array
Easy
18
0.7%
654Maximum XOR of Two Numbers in an Array
Array, Hash Table, Bit Manipulation, Trie
Medium
18
0.5%
655Smallest Subarrays With Maximum Bitwise OR
Array, Binary Search, Bit Manipulation, Sliding Window
Medium
18
0.6%
656Largest 3-Same-Digit Number in String
String
Easy
18
0.7%
657Power of Four
Math, Bit Manipulation, Recursion
Easy
18
0.5%
658New 21 Game
Math, Dynamic Programming, Sliding Window, Probability and Statistics
Medium
18
0.5%
659Sum of Mutated Array Closest to Target
Array, Binary Search, Sorting
Medium
18
0.5%
660Minimum Operations to Make the Integer Zero
Bit Manipulation, Brainteaser, Enumeration
Medium
18
0.6%
661Number of People Aware of a Secret
Dynamic Programming, Queue, Simulation
Medium
18
0.6%
662Vowel Spellchecker
Array, Hash Table, String
Medium
18
0.6%
663Design Task Manager
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
18
0.5%
664Count Elements With Maximum Frequency
Array, Hash Table, Counting
Easy
18
0.8%
665Contains Duplicate III
Array, Sliding Window, Sorting, Bucket Sort, Ordered Set
Hard
18
0.2%
666Binary Watch
Backtracking, Bit Manipulation
Easy
18
0.7%
667Find the Minimum Amount of Time to Brew Potions
Array, Simulation, Prefix Sum
Medium
18
0.6%
668Rank Teams by Votes
Array, Hash Table, String, Sorting, Counting
Medium
18
0.6%
669Last Stone Weight
Array, Heap (Priority Queue)
Easy
18
0.7%
670Minimum Operations to Convert All Elements to Zero
Array, Hash Table, Stack, Greedy, Monotonic Stack
Medium
18
0.5%
671Ones and Zeroes
Array, String, Dynamic Programming
Medium
18
0.5%
672Count Special Triplets
Array, Hash Table, Counting
Medium
18
0.5%
673Magic Squares In Grid
Array, Hash Table, Math, Matrix
Medium
18
0.6%
674Number of Ways to Paint N × 3 Grid
Dynamic Programming
Hard
18
0.8%
675Four Divisors
Array, Math
Medium
18
0.6%
676Maximum Product of Splitted Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
18
0.6%
677Find the Length of the Longest Common Prefix
Array, Hash Table, String, Trie
Medium
18
0.6%
678Design Linked List
Linked List, Design
Medium
18
0.3%
679Minimum Pair Removal to Sort Array I
Array, Hash Table, Linked List, Heap (Priority Queue), Simulation, Doubly-Linked List, Ordered Set
Easy
18
0.7%
680K-diff Pairs in an Array
Array, Hash Table, Two Pointers, Binary Search, Sorting
Medium
18
0.5%
681Number of Longest Increasing Subsequence
Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
Medium
18
0.5%
682Minimum Swaps to Arrange a Binary Grid
Array, Greedy, Matrix
Medium
18
0.7%
683Rotate Function
Array, Math, Dynamic Programming
Medium
18
0.5%
684Jump Game VII
String, Dynamic Programming, Sliding Window, Prefix Sum
Medium
18
0.4%
685Total Waviness of Numbers in Range II
Math, Dynamic Programming
Hard
18
0.6%
686Create Binary Tree From Descriptions
Array, Hash Table, Tree, Binary Tree
Medium
18
0.8%
687Maximum Building Height
Array, Math, Sorting
Hard
18
0.7%
688Spiral Matrix II
Array, Matrix, Simulation
Medium
14
0.8%
689Gray Code
Math, Backtracking, Bit Manipulation
Medium
14
0.7%
690Unique Binary Search Trees II
Dynamic Programming, Backtracking, Tree, Binary Search Tree, Binary Tree
Medium
14
0.6%
691Construct Binary Tree from Inorder and Postorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
14
0.7%
692Convert Sorted List to Binary Search Tree
Linked List, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
Medium
14
0.7%
693Word Search II
Array, String, Backtracking, Trie, Matrix
Hard
14
0.4%
694Binary Tree Paths
String, Backtracking, Tree, Depth-First Search, Binary Tree
Easy
14
0.7%
695Range Sum Query - Mutable
Array, Divide and Conquer, Design, Binary Indexed Tree, Segment Tree
Medium
14
0.4%
696Design Twitter
Hash Table, Linked List, Design, Heap (Priority Queue)
Medium
14
0.4%
697Sum of Left Leaves
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
14
0.6%
698Path Sum III
Tree, Depth-First Search, Binary Tree
Medium
14
0.5%
699LFU Cache
Hash Table, Linked List, Design, Doubly-Linked List
Hard
14
0.5%
700Predict the Winner
Array, Math, Dynamic Programming, Recursion, Game Theory
Medium
14
0.6%
701Brick Wall
Array, Hash Table
Medium
14
0.6%
7022 Keys Keyboard
Math, Dynamic Programming
Medium
14
0.6%
703Find Duplicate Subtrees
Hash Table, Tree, Depth-First Search, Binary Tree
Medium
14
0.6%
704Search in a Binary Search Tree
Tree, Binary Search Tree, Binary Tree
Easy
14
0.8%
705Kth Largest Element in a Stream
Tree, Design, Binary Search Tree, Heap (Priority Queue), Binary Tree, Data Stream
Easy
14
0.6%
706K-th Symbol in Grammar
Math, Bit Manipulation, Recursion
Medium
14
0.5%
707Custom Sort String
Hash Table, String, Sorting
Medium
14
0.7%
708Design HashSet
Array, Hash Table, Linked List, Design, Hash Function
Easy
14
0.7%
709Fair Candy Swap
Array, Hash Table, Binary Search, Sorting
Easy
14
0.7%
710Minimum Falling Path Sum
Array, Dynamic Programming, Matrix
Medium
14
0.6%
711Knight Dialer
Dynamic Programming
Medium
14
0.6%
712Reveal Cards In Increasing Order
Array, Queue, Sorting, Simulation
Medium
14
0.8%
713Unique Paths III
Array, Backtracking, Bit Manipulation, Matrix
Hard
14
0.8%
714Interval List Intersections
Array, Two Pointers, Sweep Line
Medium
14
0.7%
715Duplicate Zeros
Array, Two Pointers
Easy
14
0.5%
716Game Play Analysis I
Database
Easy
14
0.8%
717Relative Sort Array
Array, Hash Table, Sorting, Counting Sort
Easy
14
0.8%
718Minimum Cost Tree From Leaf Values
Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
Medium
14
0.7%
719Three Consecutive Odds
Array
Easy
14
0.7%
720Percentage of Users Attended a Contest
Database
Easy
14
0.6%
721Maximum Score From Removing Substrings
String, Stack, Greedy
Medium
14
0.7%
722Amount of Time for Binary Tree to Be Infected
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
14
0.7%
723Kth Largest Sum in a Binary Tree
Tree, Breadth-First Search, Sorting, Binary Tree
Medium
14
0.6%
724Divisor Game
Math, Dynamic Programming, Brainteaser, Game Theory
Easy
14
0.7%
725Fix Names in a Table
Database
Easy
14
0.6%
726Create Target Array in the Given Order
Array, Simulation
Easy
14
0.9%
727Maximum Total Damage With Spell Casting
Array, Hash Table, Two Pointers, Binary Search, Dynamic Programming, Sorting, Counting
Medium
14
0.5%
728Repeated String Match
String, String Matching
Medium
14
0.4%
729Monotonic Array
Array
Easy
14
0.6%
730Minimum Number of Days to Disconnect Island
Array, Depth-First Search, Breadth-First Search, Matrix, Strongly Connected Component
Hard
14
0.6%
731N-ary Tree Postorder Traversal
Stack, Tree, Depth-First Search
Easy
14
0.8%
732Find the Power of K-Size Subarrays I
Array, Sliding Window
Medium
14
0.6%
733Longest Subarray With Maximum Bitwise AND
Array, Bit Manipulation, Brainteaser
Medium
14
0.7%
734My Calendar I
Array, Binary Search, Design, Segment Tree, Ordered Set
Medium
14
0.6%
735Minimum Number of Swaps to Make the String Balanced
Two Pointers, String, Stack, Greedy
Medium
14
0.8%
736The Number of the Smallest Unoccupied Chair
Array, Hash Table, Heap (Priority Queue)
Medium
14
0.6%
737Sort ByEasy
14
0.8%
738Find K Pairs with Smallest Sums
Array, Heap (Priority Queue)
Medium
14
0.4%
739Longest Happy String
String, Greedy, Heap (Priority Queue)
Medium
14
0.7%
740Find Kth Bit in Nth Binary String
String, Recursion, Simulation
Medium
14
0.7%
741Parsing A Boolean Expression
String, Stack, Recursion
Hard
14
0.7%
742Moving Average from Data Stream
Array, Design, Queue, Data Stream
Easy
14
0.8%
743Final Prices With a Special Discount in a Shop
Array, Stack, Monotonic Stack
Easy
14
0.8%
744Minimum Number of Removals to Make Mountain Array
Array, Binary Search, Dynamic Programming, Greedy
Hard
14
0.5%
745Minimum Index Sum of Two Lists
Array, Hash Table, String
Easy
14
0.6%
746DI String Match
Array, Two Pointers, String, Greedy
Easy
14
0.8%
747Minimum Number of Changes to Make Binary String Beautiful
String
Medium
14
0.8%
748Count Good Triplets
Array, Enumeration
Easy
14
0.9%
749Minimum Array End
Bit Manipulation
Medium
14
0.6%
750Delete Characters to Make Fancy String
String
Easy
14
0.7%
751Smallest Even Multiple
Math, Number Theory
Easy
14
0.9%
752Count Vowel Substrings of a String
Hash Table, String
Easy
14
0.7%
753Find Score of an Array After Marking All Elements
Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
Medium
14
0.6%
754Maximum Average Pass Ratio
Array, Greedy, Heap (Priority Queue)
Medium
14
0.7%
755Make Array Elements Equal to Zero
Array, Simulation, Prefix Sum
Easy
14
0.7%
756Count Beautiful Splits in an Array
Array, Dynamic Programming
Medium
14
0.2%
757Find Center of Star Graph
Graph Theory
Easy
14
0.9%
758Number of Ways to Split Array
Array, Prefix Sum
Medium
14
0.6%
759Count Prefix and Suffix Pairs I
Array, String, Trie, Rolling Hash, String Matching, Hash Function
Easy
14
0.8%
760Counting Words With a Given Prefix
Array, String, String Matching
Easy
14
0.8%
761Construct K Palindrome Strings
Hash Table, String, Greedy, Counting
Medium
14
0.7%
762Maximum Distance in Arrays
Array, Greedy
Medium
14
0.5%
763Check if a Parentheses String Can Be Valid
String, Stack, Greedy
Medium
14
0.5%
764Minimum Length of String After Operations
Hash Table, String, Counting
Medium
14
0.8%
765Merge Two Binary Trees
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Easy
14
0.8%
766Shortest Path in a Grid with Obstacles Elimination
Array, Breadth-First Search, Matrix
Hard
14
0.5%
767Find the Difference of Two Arrays
Array, Hash Table
Easy
14
0.8%
768Shortest Unsorted Continuous Subarray
Array, Two Pointers, Stack, Greedy, Sorting, Monotonic Stack
Medium
14
0.4%
769Sort the People
Array, Hash Table, String, Sorting
Easy
14
0.8%
770Longest Nice Substring
Hash Table, String, Divide and Conquer, Bit Manipulation, Sliding Window
Easy
14
0.6%
771Product of the Last K Numbers
Array, Math, Design, Data Stream, Prefix Sum
Medium
14
0.6%
772Minimum Height Trees
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Medium
14
0.4%
773Recover a Tree From Preorder Traversal
String, Tree, Depth-First Search, Binary Tree
Hard
14
0.8%
774Construct Binary Tree from Preorder and Postorder Traversal
Array, Hash Table, Divide and Conquer, Tree, Binary Tree
Medium
14
0.8%
775Length of Longest Fibonacci Subsequence
Array, Hash Table, Dynamic Programming
Medium
14
0.6%
776Maximum Absolute Sum of Any Subarray
Array, Dynamic Programming
Medium
14
0.7%
777Closest Prime Numbers in Range
Math, Number Theory
Medium
14
0.5%
778Alternating Groups II
Array, Sliding Window
Medium
14
0.6%
779Count of Substrings Containing Every Vowel and K Consonants II
Hash Table, String, Sliding Window
Medium
14
0.4%
780Pacific Atlantic Water Flow
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
14
0.6%
781Minimum Operations to Make Binary Array Elements Equal to One I
Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum
Medium
14
0.8%
782Separate Squares I
Array, Binary Search
Medium
14
0.6%
783Sales Analysis III
Database
Easy
14
0.5%
784Lowest Common Ancestor of Deepest Leaves
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
14
0.8%
785Minimum Operations to Make Array Values Equal to K
Array, Hash Table
Easy
14
0.7%
786Maximum Sum Circular Subarray
Array, Divide and Conquer, Dynamic Programming, Queue, Monotonic Queue
Medium
14
0.5%
787Count Largest Group
Hash Table, Math, Counting
Easy
14
0.7%
788Flipping an Image
Array, Two Pointers, Bit Manipulation, Matrix, Simulation
Easy
14
0.8%
789Most Frequent Even Element
Array, Hash Table, Counting
Easy
14
0.5%
790Remove Digit From Number to Maximize Result
String, Greedy, Enumeration
Easy
14
0.5%
791Domino and Tromino Tiling
Dynamic Programming
Medium
14
0.5%
792Find Minimum Time to Reach Last Room I
Array, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
14
0.6%
793Dungeon Game
Array, Dynamic Programming, Matrix
Hard
14
0.4%
794Painting a Grid With Three Different Colors
Dynamic Programming
Hard
14
0.8%
795Find Greatest Common Divisor of Array
Array, Math, Number Theory
Easy
14
0.8%
796Divisible and Non-divisible Sums Difference
Math
Easy
14
0.9%
797Longest Palindrome by Concatenating Two Letter Words
Array, Hash Table, String, Greedy, Counting
Medium
14
0.5%
798Insert into a Binary Search Tree
Tree, Binary Search Tree, Binary Tree
Medium
14
0.7%
799Shortest Subarray with Sum at Least K
Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue
Hard
14
0.3%
800Reverse Prefix of Word
Two Pointers, String, Stack
Easy
14
0.9%
801Maximum Difference Between Increasing Elements
Array
Easy
14
0.7%
802Max Difference You Can Get From Changing an Integer
Math, Greedy
Medium
14
0.5%
803Divide Array Into Arrays With Max Difference
Array, Greedy, Sorting
Medium
14
0.8%
804Divide a String Into Groups of Size k
String, Simulation
Easy
14
0.8%
805Minimum Deletions to Make String K-Special
Hash Table, String, Greedy, Sorting, Counting
Medium
14
0.7%
806Nearest Exit from Entrance in Maze
Array, Breadth-First Search, Matrix
Medium
14
0.5%
807Find the Original Typed String I
String
Easy
14
0.7%
808Height Checker
Array, Sorting, Counting Sort
Easy
14
0.8%
809Find the Middle Index in Array
Array, Prefix Sum
Easy
14
0.7%
810Find the K-th Character in String Game II
Math, Bit Manipulation, Recursion
Hard
14
0.5%
811Find Followers Count
Database
Easy
14
0.7%
812Special Array I
Array
Easy
14
0.8%
813Find Lucky Integer in an Array
Array, Hash Table, Counting
Easy
14
0.8%
814Finding Pairs With a Certain Sum
Array, Hash Table, Design
Medium
14
0.6%
815Reschedule Meetings for Maximum Free Time II
Array, Greedy, Enumeration
Medium
14
0.6%
816Longest Continuous Increasing Subsequence
Array
Easy
14
0.5%
817Calculate Amount Paid in Taxes
Array, Simulation
Easy
14
0.7%
818Maximum Erasure Value
Array, Hash Table, Sliding Window
Medium
14
0.6%
819Minimum Penalty for a Shop
String, Prefix Sum
Medium
14
0.7%
820Maximum Unique Subarray Sum After Deletion
Array, Hash Table, Greedy
Easy
14
0.4%
821Market Analysis I
Database
Medium
14
0.6%
822Verifying an Alien Dictionary
Array, Hash Table, String
Easy
14
0.6%
823Fruits Into Baskets III
Array, Binary Search, Segment Tree, Ordered Set
Medium
14
0.4%
824Find the Maximum Number of Fruits Collected
Array, Dynamic Programming, Matrix
Hard
14
0.6%
825Shortest Distance to a Character
Array, Two Pointers, String
Easy
14
0.7%
826Max Sum of Rectangle No Larger Than K
Array, Binary Search, Matrix, Prefix Sum, Ordered Set
Hard
14
0.5%
827Maximum 69 Number
Math, Greedy
Easy
14
0.8%
82824 Game
Array, Math, Backtracking
Hard
14
0.6%
829Longest Subarray of 1's After Deleting One Element
Array, Dynamic Programming, Sliding Window
Medium
14
0.7%
830Number of Operations to Make Network Connected
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
14
0.7%
831Number of Steps to Reduce a Number to Zero
Math, Bit Manipulation
Easy
14
0.9%
832Hamming Distance
Bit Manipulation
Easy
14
0.8%
833Minimum Operations to Make Array Elements Zero
Array, Math, Bit Manipulation
Hard
14
0.6%
834Maximum Repeating Substring
String, Dynamic Programming, String Matching
Easy
14
0.4%
835Largest Perimeter Triangle
Array, Math, Greedy, Sorting
Easy
14
0.6%
836Super Egg Drop
Math, Binary Search, Dynamic Programming
Hard
14
0.3%
837Maximum Tastiness of Candy Basket
Array, Binary Search, Greedy, Sorting
Medium
14
0.7%
838Avoid Flood in The City
Array, Hash Table, Binary Search, Greedy, Heap (Priority Queue)
Medium
14
0.4%
839Remove K-Balanced Substrings
String, Stack, Simulation
Medium
14
0.3%
840Find the Distance Value Between Two Arrays
Array, Two Pointers, Binary Search, Sorting
Easy
14
0.7%
841Longest Balanced Substring I
Hash Table, String, Counting, Enumeration
Medium
14
0.7%
842Simple Bank System
Array, Hash Table, Design, Simulation
Medium
14
0.7%
843Range Sum of BST
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
14
0.9%
844Maximum Frequency Stack
Hash Table, Stack, Design, Ordered Set
Hard
14
0.7%
845Find X-Sum of All K-Long Subarrays I
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Easy
14
0.8%
846Longest Substring with At Least K Repeating Characters
Hash Table, String, Divide and Conquer, Sliding Window
Medium
14
0.5%
847Determine if Two Strings Are Close
Hash Table, String, Sorting, Counting
Medium
14
0.5%
848Number of Distinct Islands
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Sorting, Matrix, Hash Function
Medium
14
0.6%
849Minimum Score of a Path Between Two Cities
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
14
0.6%
850Reshape Data: MeltEasy
14
0.9%
851Map of Highest Peak
Array, Breadth-First Search, Matrix
Medium
14
0.8%
852Combination Sum IV
Array, Dynamic Programming
Medium
14
0.6%
853Maximum Matrix Sum
Array, Greedy, Matrix
Medium
14
0.7%
854Online Election
Array, Hash Table, Binary Search, Design
Medium
14
0.5%
855Wiggle Sort II
Array, Divide and Conquer, Greedy, Sorting, Quickselect
Medium
14
0.4%
856Smallest Subtree with all the Deepest Nodes
Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
14
0.8%
857Maximum Square Area by Removing Fences From a Field
Array, Hash Table, Enumeration
Medium
14
0.5%
858Find the Largest Area of Square Inside Two Rectangles
Array, Math, Geometry
Medium
14
0.7%
859N-Repeated Element in Size 2N Array
Array, Hash Table
Easy
14
0.8%
860Take K of Each Character From Left and Right
Hash Table, String, Sliding Window
Medium
14
0.5%
861Exclusive Time of Functions
Array, Stack
Medium
14
0.7%
862Subtract the Product and Sum of Digits of an Integer
Math
Easy
14
0.9%
863House Robber III
Dynamic Programming, Tree, Depth-First Search, Binary Tree
Medium
14
0.6%
864Longest Balanced Substring II
Hash Table, String, Prefix Sum
Medium
14
0.4%
865Champagne Tower
Dynamic Programming
Medium
14
0.6%
866Special Binary String
String, Divide and Conquer, Sorting
Hard
14
0.8%
867Concatenation of Consecutive Binary Numbers
Math, Bit Manipulation, Simulation
Medium
14
0.7%
868Largest Submatrix With Rearrangements
Array, Greedy, Sorting, Matrix
Medium
14
0.8%
869Maximum Amount of Money Robot Can Earn
Array, Dynamic Programming, Matrix
Medium
14
0.5%
870Closest Equal Element Queries
Array, Hash Table, Binary Search
Medium
14
0.5%
871Mirror Distance of an Integer
Math
Easy
14
0.9%
872Two Furthest Houses With Different Colors
Array, Greedy
Easy
14
0.7%
873Longest Increasing Path in a Matrix
Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Memoization, Matrix
Hard
14
0.6%
874Words Within Two Edits of Dictionary
Array, String, Trie
Medium
14
0.7%
875Guess Number Higher or Lower II
Math, Dynamic Programming, Game Theory
Medium
14
0.5%
876Valid Mountain Array
Array
Easy
14
0.4%
877Total Cost to Hire K Workers
Array, Two Pointers, Heap (Priority Queue), Simulation
Medium
14
0.4%
878Flatten Nested List Iterator
Stack, Tree, Depth-First Search, Design, Queue, Iterator
Medium
14
0.7%
879Nth Digit
Math, Binary Search
Medium
14
0.4%
880Minimum Cost of Buying Candies With Discount
Array, Greedy, Sorting
Easy
14
0.7%
881Bulls and Cows
Hash Table, String, Counting
Medium
14
0.5%
882Earliest Finish Time for Land and Water Rides I
Array, Two Pointers, Binary Search, Greedy, Sorting
Easy
14
0.7%
883Number of Ways to Assign Edge Weights II
Array, Math, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search
Hard
14
0.7%
884Process String with Special Operations I
String, Simulation
Medium
14
0.7%
885Number of ZigZag Arrays II
Math, Dynamic Programming
Hard
14
0.7%
886Unique Binary Search Trees
Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree
Medium
8
0.6%
887Palindrome Partitioning II
String, Dynamic Programming
Hard
8
0.4%
888Maximum Gap
Array, Sorting, Bucket Sort, Radix Sort
Medium
8
0.5%
889Bulb Switcher
Math, Brainteaser
Medium
8
0.6%
890Russian Doll Envelopes
Array, Binary Search, Dynamic Programming, Sorting
Hard
8
0.4%
891Kth Smallest Element in a Sorted Matrix
Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
Medium
8
0.6%
892Find Right Interval
Array, Binary Search, Sorting
Medium
8
0.6%
893Find Mode in Binary Search Tree
Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
8
0.6%
894Out of Boundary Paths
Dynamic Programming
Medium
8
0.5%
895Is Graph Bipartite?
Depth-First Search, Breadth-First Search, Union-Find, Graph Theory
Medium
8
0.6%
896Design Circular Queue
Array, Linked List, Design, Queue
Medium
8
0.5%
897Score of Parentheses
String, Stack
Medium
8
0.6%
898Stone Game
Array, Math, Dynamic Programming, Game Theory
Medium
8
0.7%
899Distribute Coins in Binary Tree
Tree, Depth-First Search, Binary Tree
Medium
8
0.8%
900Longest Arithmetic Subsequence
Array, Hash Table, Binary Search, Dynamic Programming
Medium
8
0.5%
901Flower Planting With No Adjacent
Depth-First Search, Breadth-First Search, Graph Theory
Medium
8
0.5%
902Longest Duplicate Substring
String, Binary Search, Sliding Window, Rolling Hash, Suffix Array, Hash Function
Hard
8
0.3%
903Minimum Falling Path Sum II
Array, Dynamic Programming, Matrix
Hard
8
0.6%
904Stone Game II
Array, Math, Dynamic Programming, Prefix Sum, Game Theory
Medium
8
0.7%
905Find Resultant Array After Removing Anagrams
Array, Hash Table, String, Sorting
Easy
8
0.7%
906Group the People Given the Group Size They Belong To
Array, Hash Table, Greedy
Medium
8
0.9%
907Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
Medium
8
0.6%
908Average Salary Excluding the Minimum and Maximum Salary
Array, Sorting
Easy
8
0.6%
909The kth Factor of n
Math, Number Theory
Medium
8
0.7%
910Water Bottles
Math, Simulation
Easy
8
0.7%
911Patients With a Condition
Database
Easy
8
0.4%
912Minimum Time to Make Rope Colorful
Array, String, Dynamic Programming, Greedy
Medium
8
0.7%
913Sum of All Subset XOR Totals
Array, Math, Backtracking, Bit Manipulation, Combinatorics, Enumeration
Easy
8
0.9%
914Maximum Alternating Subsequence Sum
Array, Dynamic Programming
Medium
8
0.6%
915Minimum Number of Operations to Make Array Continuous
Array, Hash Table, Binary Search, Sliding Window
Hard
8
0.5%
916Time Needed to Buy Tickets
Array, Queue, Simulation
Easy
8
0.7%
917Count Numbers with Unique Digits
Math, Dynamic Programming, Backtracking
Medium
8
0.6%
918Most Frequent Subtree Sum
Hash Table, Tree, Depth-First Search, Binary Tree
Medium
8
0.7%
919Filling Bookcase Shelves
Array, Dynamic Programming
Medium
8
0.7%
920Minimum Swaps to Group All 1's Together II
Array, Sliding Window
Medium
8
0.7%
921Split Linked List in Parts
Linked List
Medium
8
0.7%
922Regions Cut By Slashes
Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Matrix
Medium
8
0.8%
923Minimized Maximum of Products Distributed to Any Store
Array, Binary Search, Greedy
Medium
8
0.6%
924Maximum Number of Points with Cost
Array, Dynamic Programming, Matrix
Medium
8
0.4%
925Maximal Square
Array, Dynamic Programming, Matrix
Medium
8
0.5%
926Final Array State After K Multiplication Operations I
Array, Math, Heap (Priority Queue), Simulation
Easy
8
0.9%
927Sum of Digits of String After Convert
String, Simulation
Easy
8
0.7%
928Find Missing Observations
Array, Math, Simulation
Medium
8
0.6%
929Linked List in Binary Tree
Linked List, Tree, Depth-First Search, Binary Tree
Medium
8
0.5%
930Sum of Prefix Scores of Strings
Array, String, Trie, Counting
Hard
8
0.6%
931Make Sum Divisible by P
Array, Hash Table, Prefix Sum
Medium
8
0.4%
932Sentence Similarity III
Array, Two Pointers, String
Medium
8
0.5%
933Divide Players Into Teams of Equal Skill
Array, Hash Table, Two Pointers, Sorting
Medium
8
0.7%
934Divide Intervals Into Minimum Number of Groups
Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
Medium
8
0.6%
935Maximum Product of Two Elements in an Array
Array, Sorting, Heap (Priority Queue)
Easy
8
0.8%
936Split a String Into the Max Number of Unique Substrings
Hash Table, String, Backtracking
Medium
8
0.7%
937Find Minimum Operations to Make All Elements Divisible by Three
Array, Math
Easy
8
0.9%
938Circular Sentence
String
Easy
8
0.7%
939Maximum XOR for Each Query
Array, Bit Manipulation, Prefix Sum
Medium
8
0.8%
940Find a Safe Walk Through a Grid
Array, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path
Medium
8
0.3%
941Degree of an Array
Array, Hash Table
Easy
8
0.6%
942Maximum Sum BST in Binary Tree
Dynamic Programming, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Hard
8
0.5%
943Flip Columns For Maximum Number of Equal Rows
Array, Hash Table, Matrix
Medium
8
0.8%
944Nim Game
Math, Brainteaser, Game Theory
Easy
8
0.6%
945Special Array II
Array, Binary Search, Prefix Sum
Medium
8
0.5%
946Number of Visible People in a Queue
Array, Stack, Monotonic Stack
Hard
8
0.7%
947Check if Array is Good
Array, Hash Table, Sorting
Easy
8
0.6%
948Sliding Window Median
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
8
0.4%
949Count Univalue Subtrees
Tree, Depth-First Search, Binary Tree
Medium
8
0.6%
950Count Special Subsequences
Array, Hash Table, Math, Enumeration
Medium
8
0.3%
951Word Subsets
Array, Hash Table, String
Medium
8
0.6%
952Minimize XOR
Greedy, Bit Manipulation
Medium
8
0.6%
953First Completely Painted Row or Column
Array, Hash Table, Matrix
Medium
8
0.6%
954Maximum and Minimum Sums of at Most Size K Subsequences
Array, Math, Dynamic Programming, Sorting, Combinatorics
Medium
8
0.2%
955Grid Game
Array, Matrix, Prefix Sum
Medium
8
0.6%
956Paint House IV
Array, Dynamic Programming
Medium
8
0.5%
957Largest Local Values in a Matrix
Array, Matrix
Easy
8
0.9%
958Convert Binary Number in a Linked List to Integer
Linked List, Math
Easy
8
0.8%
959Find Original Array From Doubled Array
Array, Hash Table, Greedy, Sorting
Medium
8
0.4%
960Shortest Path in a Hidden Grid
Array, Depth-First Search, Breadth-First Search, Matrix, Interactive
Medium
8
0.4%
961Construct Quad Tree
Array, Divide and Conquer, Tree, Matrix
Medium
8
0.8%
962Count Pairs Whose Sum is Less than Target
Array, Two Pointers, Binary Search, Sorting
Easy
8
0.9%
963Find Unique Binary String
Array, Hash Table, String, Backtracking
Medium
8
0.8%
964Reach a Number
Math, Binary Search
Medium
8
0.5%
965Decrypt String from Alphabet to Integer Mapping
String
Easy
8
0.8%
966Count Vowel Strings in Ranges
Array, String, Prefix Sum
Medium
8
0.7%
967Count Total Number of Colored Cells
Math
Medium
8
0.7%
968Maximum Subsequence Score
Array, Greedy, Sorting, Heap (Priority Queue)
Medium
8
0.5%
969Walls and Gates
Array, Breadth-First Search, Matrix
Medium
8
0.6%
970Beautiful Arrangement II
Array, Math
Medium
8
0.6%
971Last Stone Weight II
Array, Dynamic Programming
Medium
8
0.6%
972Find the Minimum and Maximum Number of Nodes Between Critical Points
Linked List
Medium
8
0.7%
973Find All Possible Recipes from Given Supplies
Array, Hash Table, String, Graph Theory, Topological Sort
Medium
8
0.6%
974Maximum Units on a Truck
Array, Greedy, Sorting
Easy
8
0.7%
975Shifting Letters
Array, String, Prefix Sum
Medium
8
0.5%
976Grumpy Bookstore Owner
Array, Sliding Window
Medium
8
0.6%
977Largest Number At Least Twice of Others
Array, Sorting
Easy
8
0.5%
978Solving Questions With Brainpower
Array, Dynamic Programming
Medium
8
0.6%
979Longest Univalue Path
Tree, Depth-First Search, Binary Tree
Medium
8
0.4%
980Count Good Triplets in an Array
Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
Hard
8
0.7%
981Count Equal and Divisible Pairs in an Array
Array
Easy
8
0.8%
982Adding Spaces to a String
Array, Two Pointers, String, Simulation
Medium
8
0.7%
983Equal Row and Column Pairs
Array, Hash Table, Matrix, Simulation
Medium
8
0.7%
984Shortest String That Contains Three Strings
String, Greedy, Enumeration
Medium
8
0.3%
985Count of Interesting Subarrays
Array, Hash Table, Prefix Sum
Medium
8
0.6%
986Minimum Number Game
Array, Sorting, Heap (Priority Queue), Simulation
Easy
8
0.9%
987Remove Methods From Project
Depth-First Search, Breadth-First Search, Graph Theory
Medium
8
0.5%
988Merge Two 2D Arrays by Summing Values
Array, Hash Table, Two Pointers
Easy
8
0.8%
989Move Pieces to Obtain a String
Two Pointers, String
Medium
8
0.6%
990Number of Equivalent Domino Pairs
Array, Hash Table, Counting
Easy
8
0.6%
991Maximum Number of Tasks You Can Assign
Array, Two Pointers, Binary Search, Greedy, Queue, Sorting, Monotonic Queue
Hard
8
0.5%
992Furthest Building You Can Reach
Array, Greedy, Heap (Priority Queue)
Medium
8
0.5%
993Find Maximum Number of Non Intersecting Substrings
Hash Table, String, Dynamic Programming, Greedy
Medium
8
0.3%
994Maximum Sum of Edge Values in a Graph
Math, Greedy, Graph Theory
Hard
8
0.4%
995Minimum Moves to Clean the Classroom
Array, Hash Table, Bit Manipulation, Breadth-First Search, Matrix
Medium
8
0.3%
996Clumsy Factorial
Math, Stack, Simulation
Medium
8
0.6%
997Maximum Candies You Can Get from Boxes
Array, Breadth-First Search, Graph Theory
Hard
8
0.7%
998Find the Lexicographically Largest String From the Box I
Two Pointers, String, Enumeration
Medium
8
0.4%
999Number of Sub-arrays With Odd Sum
Array, Math, Dynamic Programming, Prefix Sum
Medium
8
0.6%
1000Minimum Operations to Make the Array Alternating
Array, Hash Table, Greedy, Counting
Medium
8
0.4%
1001Lexicographically Minimum String After Removing Stars
Hash Table, String, Stack, Greedy, Heap (Priority Queue)
Medium
8
0.5%
1002Maximum Difference Between Even and Odd Frequency II
String, Sliding Window, Enumeration, Prefix Sum
Hard
8
0.5%
1003Maximum Difference Between Adjacent Elements in a Circular Array
Array
Easy
8
0.8%
1004Find Closest Node to Given Two Nodes
Depth-First Search, Graph Theory
Medium
8
0.5%
1005Generate Tag for Video Caption
String, Simulation
Easy
8
0.3%
1006Longest Happy Prefix
String, Rolling Hash, String Matching, Hash Function
Hard
8
0.5%
1007Sum of k-Mirror Numbers
Math, Enumeration
Hard
8
0.6%
1008Insert Greatest Common Divisors in Linked List
Linked List, Math, Number Theory
Medium
8
0.9%
1009Scramble String
String, Dynamic Programming
Hard
8
0.4%
1010Largest Number After Digit Swaps by Parity
Sorting, Heap (Priority Queue)
Easy
8
0.7%
1011Sort the Jumbled Numbers
Array, Sorting
Medium
8
0.6%
1012Find the Original Typed String II
String, Dynamic Programming, Prefix Sum
Hard
8
0.5%
1013Student Attendance Record I
String
Easy
8
0.5%
1014Reschedule Meetings for Maximum Free Time I
Array, Greedy, Sliding Window
Medium
8
0.5%
1015Partition Array Into Three Parts With Equal Sum
Array, Greedy
Easy
8
0.4%
1016Calculator with Method ChainingEasy
8
0.8%
1017The Earliest and Latest Rounds Where Players Compete
Dynamic Programming, Memoization
Hard
8
0.7%
1018Orderly Queue
Math, String, Sorting
Hard
8
0.7%
1019Minimum Difference in Sums After Removal of Elements
Array, Dynamic Programming, Heap (Priority Queue)
Hard
8
0.7%
1020MemoizeMedium
8
0.7%
1021Check if Two Chessboard Squares Have the Same Color
Math, String
Easy
8
0.7%
1022Add Two PromisesEasy
8
0.9%
1023Maximize Subarrays After Removing One Conflicting Pair
Array, Segment Tree, Enumeration, Prefix Sum
Hard
8
0.6%
1024Count Number of Maximum Bitwise-OR Subsets
Array, Backtracking, Bit Manipulation, Enumeration
Medium
8
0.9%
1025Minimum Cuts to Divide a Circle
Math, Geometry
Easy
8
0.6%
1026Sum of Unique Elements
Array, Hash Table, Counting
Easy
8
0.8%
1027Smallest String With Swaps
Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting
Medium
8
0.6%
1028Rearranging Fruits
Array, Hash Table, Greedy, Sort
Hard
8
0.6%
1029Broken Calculator
Math, Greedy
Medium
8
0.6%
1030The Number of Beautiful Subsets
Array, Hash Table, Math, Dynamic Programming, Backtracking, Sorting, Combinatorics
Medium
8
0.5%
1031Difference Between Element Sum and Digit Sum of an Array
Array, Math
Easy
8
0.9%
1032The Maze
Array, Depth-First Search, Breadth-First Search, Matrix
Medium
8
0.6%
1033Range Product Queries of Powers
Array, Bit Manipulation, Prefix Sum
Medium
8
0.6%
1034Number of Distinct Substrings in a String
String, Trie, Rolling Hash, Suffix Array, Hash Function
Medium
8
0.6%
1035Construct Binary Tree from String
String, Stack, Tree, Depth-First Search, Binary Tree
Medium
8
0.6%
1036Pass the Pillow
Math, Simulation
Easy
8
0.6%
1037Minimum Interval to Include Each Query
Array, Binary Search, Sweep Line, Sorting, Heap (Priority Queue)
Hard
8
0.5%
1038Bitwise AND of Numbers Range
Bit Manipulation
Medium
8
0.5%
1039Sort Items by Groups Respecting Dependencies
Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
8
0.7%
1040Letter Case Permutation
String, Backtracking, Bit Manipulation
Medium
8
0.8%
1041Alice and Bob Playing Flower Game
Math
Medium
8
0.6%
1042Find Words Containing Character
Array, String
Easy
8
0.9%
1043Generate Binary Strings Without Adjacent Zeros
String, Backtracking, Bit Manipulation
Medium
8
0.9%
1044Find Closest Person
Math
Easy
8
0.9%
1045Choose K Elements With Maximum Sum
Array, Sorting, Heap (Priority Queue)
Medium
8
0.3%
1046A Number After a Double Reversal
Math
Easy
8
0.8%
1047Minimum Number of People to Teach
Array, Hash Table, Greedy
Medium
8
0.7%
1048Beautiful Arrangement
Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
Medium
8
0.6%
1049Maximum Number of Points From Grid Queries
Array, Two Pointers, Breadth-First Search, Union-Find, Sorting, Heap (Priority Queue), Matrix
Hard
8
0.6%
1050Reverse Nodes in Even Length Groups
Linked List
Medium
8
0.6%
1051Find the Winning Player in Coin Game
Math, Simulation, Game Theory
Easy
8
0.5%
1052Lexicographically Smallest Equivalent String
String, Union-Find
Medium
8
0.8%
1053Find Subarrays With Equal Sum
Array, Hash Table
Easy
8
0.7%
1054Fraction to Recurring Decimal
Hash Table, Math, String
Medium
8
0.3%
1055Minimum Common Value
Array, Hash Table, Two Pointers, Binary Search
Easy
8
0.6%
1056Maximum Palindromes After Operations
Array, Hash Table, String, Greedy, Sorting, Counting
Medium
8
0.5%
1057Make Two Arrays Equal by Reversing Subarrays
Array, Hash Table, Sorting
Easy
8
0.8%
1058Count Number of Bad Pairs
Array, Hash Table, Math, Counting
Medium
8
0.5%
1059Dota2 Senate
String, Greedy, Queue
Medium
8
0.5%
1060Adjacent Increasing Subarrays Detection I
Array
Easy
8
0.5%
1061Maximum Number of Distinct Elements After Operations
Array, Greedy, Sorting
Medium
8
0.5%
1062K Radius Subarray Averages
Array, Sliding Window
Medium
8
0.5%
1063Robot Bounded In Circle
Math, String, Simulation
Medium
8
0.6%
1064Non-negative Integers without Consecutive Ones
Dynamic Programming
Hard
8
0.4%
1065Minimum Moves to Reach Target in Grid
Math
Hard
8
0.2%
1066Largest Positive Integer That Exists With Its Negative
Array, Hash Table, Two Pointers, Sorting
Easy
8
0.7%
1067Generate Fibonacci SequenceEasy
8
0.8%
1068Find X-Sum of All K-Long Subarrays II
Array, Hash Table, Sliding Window, Heap (Priority Queue)
Hard
8
0.4%
1069Number of Ways to Form a Target String Given a Dictionary
Array, String, Dynamic Programming
Hard
8
0.6%
1070Minimum One Bit Operations to Make Integers Zero
Math, Dynamic Programming, Bit Manipulation, Recursion, Memoization
Hard
8
0.8%
1071Tiling a Rectangle with the Fewest Squares
Backtracking
Hard
8
0.6%
1072Design Tic-Tac-Toe
Array, Hash Table, Design, Matrix, Simulation
Medium
8
0.6%
1073Maximum Number of Operations to Move Ones to the End
String, Greedy, Counting
Medium
8
0.7%
1074Delete Duplicate Folders in System
Array, Hash Table, String, Depth-First Search, Trie, Sorting, Hash Function
Hard
8
0.8%
1075Max Chunks To Make Sorted II
Array, Stack, Greedy, Sorting, Monotonic Stack
Hard
8
0.5%
1076Count the Number of Substrings With Dominant Ones
String, Enumeration
Medium
8
0.4%
1077Check If All 1's Are at Least Length K Places Away
Array
Easy
8
0.6%
10781-bit and 2-bit Characters
Array
Easy
8
0.5%
1079Add One Row to Tree
Tree, Depth-First Search, Breadth-First Search, Binary Tree
Medium
8
0.6%
1080Keep Multiplying Found Values by Two
Array, Hash Table, Sorting, Simulation
Easy
8
0.8%
1081Decoded String at Index
String, Stack
Medium
8
0.4%
1082Find Beautiful Indices in the Given Array I
Two Pointers, String, Binary Search, Rolling Hash, String Matching, Hash Function
Medium
8
0.4%
1083Smallest Integer Divisible by K
Hash Table, Math
Medium
8
0.5%
1084Maximum Running Time of N Computers
Array, Binary Search, Greedy, Sorting
Hard
8
0.6%
1085Employee Free Time
Array, Sweep Line, Sorting, Heap (Priority Queue)
Hard
8
0.7%
1086Count Partitions with Even Sum Difference
Array, Math, Prefix Sum
Easy
8
0.9%
1087Closest Binary Search Tree Value
Binary Search, Tree, Depth-First Search, Binary Search Tree, Binary Tree
Easy
8
0.5%
1088Tree Node
Database
Medium
8
0.8%
1089Student Attendance Record II
Dynamic Programming
Hard
8
0.6%
1090The Skyline Problem
Array, Divide and Conquer, Binary Indexed Tree, Segment Tree, Sweep Line, Sorting, Heap (Priority Queue), Ordered Set
Hard
8
0.5%
1091Cinema Seat Allocation
Array, Hash Table, Greedy, Bit Manipulation
Medium
8
0.4%
1092Put Marbles in Bags
Array, Greedy, Sorting, Heap (Priority Queue)
Hard
8
0.7%
1093Count Number of Trapezoids I
Array, Hash Table, Math, Geometry
Medium
8
0.5%
1094Count Mentions Per User
Array, Math, Sorting, Simulation
Medium
8
0.5%
1095Battleships in a Board
Array, Depth-First Search, Matrix
Medium
8
0.8%
1096Number of Ways to Divide a Long Corridor
Math, String, Dynamic Programming
Hard
8
0.5%
1097Design Spreadsheet
Array, Hash Table, String, Design, Matrix
Medium
8
0.7%
1098Maximum Frequency of an Element After Performing Operations II
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Hard
8
0.5%
1099Count Square Sum Triples
Math, Enumeration
Easy
8
0.8%
1100Minimum Moves to Balance Circular Array
Array, Greedy, Sorting
Medium
8
0.4%
1101Delete Columns to Make Sorted II
Array, String, Greedy
Medium
8
0.5%
1102Check if All A's Appears Before All B's
String
Easy
8
0.7%
1103Circular Array Loop
Array, Hash Table, Two Pointers
Medium
8
0.4%
1104Number of Good Paths
Array, Hash Table, Tree, Union-Find, Graph Theory, Sorting
Hard
8
0.6%
1105Apple Redistribution into Boxes
Array, Greedy, Sorting
Easy
8
0.8%
1106Analyze Subscription Conversion
Database
Medium
8
0.7%
1107Meeting Rooms III
Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
Hard
8
0.5%
1108Find Minimum Cost to Remove Array Elements
Array, Dynamic Programming
Medium
8
0.2%
1109Minimum Moves to Convert String
String, Greedy
Easy
8
0.6%
1110Mini Parser
String, Stack, Depth-First Search
Medium
8
0.4%
1111Soup Servings
Math, Dynamic Programming, Probability and Statistics
Medium
8
0.6%
1112Numbers With Same Consecutive Differences
Backtracking, Breadth-First Search
Medium
8
0.6%
1113Max Dot Product of Two Subsequences
Array, Dynamic Programming
Hard
8
0.7%
1114Long Pressed Name
Two Pointers, String
Easy
8
0.3%
1115Arithmetic Slices II - Subsequence
Array, Dynamic Programming
Hard
8
0.6%
1116Find Missing Elements
Array, Hash Table, Sorting
Easy
8
0.8%
1117Total Hamming Distance
Array, Math, Bit Manipulation
Medium
8
0.5%
1118Number of Perfect Pairs
Array, Math, Two Pointers, Sorting
Medium
8
0.3%
1119Construct the Minimum Bitwise Array I
Array, Bit Manipulation
Easy
8
0.9%
1120Root Equals Sum of Children
Tree, Binary Tree
Easy
8
0.9%
1121Minimum Cost Path with Edge Reversals
Graph Theory, Heap (Priority Queue), Shortest Path
Medium
8
0.6%
1122Minimize String Length
Hash Table, String
Easy
8
0.8%
1123Rectangle Area
Math, Geometry
Medium
8
0.5%
1124Maximum Difference Between Node and Ancestor
Tree, Depth-First Search, Binary Tree
Medium
8
0.8%
1125Find Words That Can Be Formed by Characters
Array, Hash Table, String, Counting
Easy
8
0.7%
1126Find And Replace in String
Array, Hash Table, String, Sorting
Medium
8
0.5%
1127Binary Gap
Bit Manipulation
Easy
8
0.7%
1128Trionic Array II
Array, Dynamic Programming
Hard
8
0.5%
1129Convert 1D Array Into 2D Array
Array, Matrix, Simulation
Easy
8
0.7%
1130GCD of Odd and Even Sums
Math, Number Theory
Easy
8
0.9%
1131Self Crossing
Array, Math, Geometry
Hard
8
0.4%
1132Replace Non-Coprime Numbers in Array
Array, Math, Stack, Number Theory
Hard
8
0.6%
1133Linked List Components
Array, Hash Table, Linked List
Medium
8
0.6%
1134The Dining Philosophers
Concurrency
Medium
8
0.5%
1135Sort Array By Parity II
Array, Two Pointers, Sorting
Easy
8
0.7%
1136Max Consecutive Ones II
Array, Dynamic Programming, Sliding Window
Medium
8
0.5%
1137Partition to K Equal Sum Subsets
Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
Medium
8
0.4%
1138Construct the Lexicographically Largest Valid Sequence
Array, Backtracking
Medium
8
0.7%
1139Minimum Knight Moves
Breadth-First Search
Medium
8
0.4%
1140Tenth Line
Shell
Easy
8
0.4%
1141Remove Invalid Parentheses
String, Backtracking, Breadth-First Search
Hard
8
0.5%
1142Select DataEasy
8
0.8%
1143Check Digitorial Permutation
Math, Counting
Medium
8
0.5%
1144Minimum Changes To Make Alternating Binary String
String
Easy
8
0.7%
1145Swap Adjacent in LR String
Two Pointers, String
Medium
8
0.4%
1146Find the Number of Ways to Place People I
Array, Math, Geometry, Sorting, Enumeration
Medium
8
0.6%
1147Binary Tree Level Order Traversal II
Tree, Breadth-First Search, Binary Tree
Medium
8
0.7%
1148The K Weakest Rows in a Matrix
Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
Easy
8
0.7%
1149Fancy Sequence
Math, Design, Segment Tree, Number Theory
Hard
8
0.4%
1150Maximum Frequency of an Element After Performing Operations I
Array, Binary Search, Sliding Window, Sorting, Prefix Sum
Medium
8
0.4%
1151Maximum Frequency After Subarray Operation
Array, Hash Table, Dynamic Programming, Greedy, Enumeration, Prefix Sum
Medium
8
0.3%
1152Daily Leads and Partners
Database
Easy
8
0.9%
1153Find the Closest Palindrome
Math, String
Hard
8
0.3%
1154Construct Product Matrix
Array, Matrix, Prefix Sum
Medium
8
0.5%
1155Equal Sum Grid Partition I
Array, Matrix, Enumeration, Prefix Sum
Medium
8
0.5%
1156Alien Dictionary
Array, String, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort
Hard
8
0.4%
1157Count Unguarded Cells in the Grid
Array, Matrix, Simulation
Medium
8
0.7%
1158Human Traffic of Stadium
Database
Hard
8
0.5%
1159Maximal Score After Applying K Operations
Array, Greedy, Heap (Priority Queue)
Medium
8
0.6%
1160Find the Largest Almost Missing Integer
Array, Hash Table
Easy
8
0.4%
1161Maximum Ascending Subarray Sum
Array
Easy
8
0.7%
1162Smallest Number in Infinite Set
Hash Table, Design, Heap (Priority Queue), Ordered Set
Medium
8
0.7%
1163Merge In Between Linked Lists
Linked List
Medium
8
0.8%
1164Shortest Common Supersequence
String, Dynamic Programming
Hard
8
0.6%
1165Minimum Distance to the Target Element
Array
Easy
8
0.6%
1166Classes With at Least 5 Students
Database
Easy
8
0.6%
1167Beautiful Array
Array, Math, Divide and Conquer
Medium
8
0.7%
1168Frog Jump
Array, Dynamic Programming
Hard
8
0.5%
1169Minimum Operations to Reduce an Integer to 0
Dynamic Programming, Greedy, Bit Manipulation
Medium
8
0.6%
1170Maximize the Distance Between Points on a Square
Array, Math, Binary Search, Geometry, Sorting
Hard
8
0.5%
1171Insertion Sort List
Linked List, Sorting
Medium
8
0.6%
1172Greatest Sum Divisible by Three
Array, Dynamic Programming, Greedy, Sorting
Medium
8
0.6%
1173Substrings of Size Three with Distinct Characters
Hash Table, String, Sliding Window, Counting
Easy
8
0.8%
1174Jump Game IX
Array, Dynamic Programming
Medium
8
0.5%
1175Minimize Hamming Distance After Swap Operations
Array, Depth-First Search, Union-Find
Medium
8
0.7%
1176Binary Number with Alternating Bits
Bit Manipulation
Easy
8
0.7%
1177Build an Array With Stack Operations
Array, Stack, Simulation
Medium
8
0.8%
1178Swapping Nodes in a Linked List
Linked List, Two Pointers
Medium
8
0.7%
1179Design Snake Game
Array, Hash Table, Design, Queue, Simulation
Medium
8
0.4%
1180Minimum Moves to Equal Array Elements
Array, Math
Medium
8
0.6%
1181Design Bounded Blocking Queue
Concurrency
Medium
8
0.7%
1182Three Divisors
Math, Enumeration, Number Theory
Easy
8
0.6%
1183Number of Boomerangs
Array, Hash Table, Math
Medium
8
0.6%
1184Check If Array Pairs Are Divisible by k
Array, Hash Table, Counting
Medium
8
0.5%
1185Number of Unique Subjects Taught by Each Teacher
Database
Easy
8
0.9%
1186Range Addition II
Array, Math
Easy
8
0.6%
1187Minimum Number of Coins to be Added
Array, Greedy, Sorting
Medium
8
0.6%
1188Get Equal Substrings Within Budget
String, Binary Search, Sliding Window, Prefix Sum
Medium
8
0.6%
1189Minimum Jumps to Reach Home
Array, Hash Table, Breadth-First Search
Medium
8
0.3%
1190Reverse Words in a String III
Two Pointers, String
Easy
8
0.8%
1191Weighted Word Mapping
Array, String, Simulation
Easy
8
0.9%
1192Stock Price Fluctuation
Hash Table, Design, Heap (Priority Queue), Data Stream, Ordered Set
Medium
8
0.5%
1193Maximum Ice Cream Bars
Array, Greedy, Sorting, Counting Sort
Medium
8
0.8%
1194Maximum Number of Balloons
Hash Table, String, Counting
Easy
8
0.6%
1195Minimum Swaps To Make Sequences Increasing
Array, Dynamic Programming
Hard
8
0.4%
1196Number of ZigZag Arrays I
Dynamic Programming, Prefix Sum
Hard
8
0.5%
1197Count the Number of Inversions
Array, Dynamic Programming
Hard
8
0.3%
1198Word Frequency
Shell
Medium
8
0.3%
1199Employee Importance
Array, Hash Table, Tree, Depth-First Search, Breadth-First Search
Medium
8
0.7%
1200Count Square Submatrices with All Ones
Array, Dynamic Programming, Matrix
Medium
8
0.8%

How to read this list

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

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