1 Two Sum Array Hash Table
Easy 100
0.6% 2 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 98
0.4% 3 Minimum Operations to Make a Uni-Value Grid Array Math Sorting Matrix
Medium 94
0.7% 4 Valid Parentheses String Stack
Easy 86
0.4% 5 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 83
0.4% 6 Longest Common Prefix Array String Trie
Easy 83
0.5% 7 Move Zeroes Array Two Pointers
Easy 83
0.6% 8 Merge Sorted Array Array Two Pointers Sorting
Easy 80
0.6% 9 Valid Anagram Hash Table String Sorting
Easy 80
0.7% 10 Group Anagrams Array Hash Table String Sorting
Medium 75
0.7% 11 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 75
0.6% 12 Rotate Array Array Math Two Pointers
Medium 75
0.5% 13 3Sum Array Two Pointers Sorting
Medium 63
0.4% 14 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 63
0.7% 15 House Robber Array Dynamic Programming
Medium 63
0.5% 16 Partition Equal Subset Sum Array Dynamic Programming
Medium 63
0.5% 17 Longest Consecutive Sequence Array Hash Table Union-Find
Medium 63
0.5% 18 String Compression Two Pointers String
Medium 63
0.6% 19 Reverse String Two Pointers String
Easy 63
0.8% 20 First Unique Character in a String Hash Table String Queue Counting
Easy 63
0.7% 21 Merge Intervals Array Sorting
Medium 63
0.5% 22 Generate Parentheses String Dynamic Programming Backtracking
Medium 63
0.8% 23 Reverse Vowels of a String Two Pointers String
Easy 63
0.6% 24 Add Two Numbers Linked List Math Recursion
Medium 53
0.5% 25 Palindrome Number Math
Easy 53
0.6% 26 Maximum Difference Between Node and Ancestor Tree Depth-First Search Binary Tree
Medium 53
0.8% 27 Reverse Integer Math
Medium 53
0.3% 28 Two Sum II - Input Array Is Sorted Array Two Pointers Binary Search
Medium 53
0.7% 29 Pow(x, n) Math Recursion
Medium 53
0.4% 30 Duplicate Emails Database
Easy 53
0.7% 31 Count Salary Categories Database
Medium 53
0.6% 32 Multiply Strings Math String Simulation
Medium 53
0.4% 33 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 53
0.5% 34 Reverse Words in a String Two Pointers String
Medium 53
0.6% 35 Unique Paths Math Dynamic Programming Combinatorics
Medium 53
0.7% 36 Edit Distance String Dynamic Programming
Medium 53
0.6% 37 Roman to Integer Hash Table Math String
Easy 53
0.7% 38 Counter Easy 53
0.8% 39 Reverse Linked List Linked List Recursion
Easy 53
0.8% 40 Sort Characters By Frequency Hash Table String Sorting Heap (Priority Queue) Bucket Sort Counting
Medium 53
0.8% 41 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 53
0.7% 42 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 53
0.7% 43 First Missing Positive Array Hash Table
Hard 53
0.4% 44 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 53
0.5% 45 Merge Two Sorted Lists Linked List Recursion
Easy 53
0.7% 46 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 53
0.5%