1 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 100
0.5% 2 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 95
0.4% 3 Lexicographically Smallest String After Operations With Constraint String Greedy
Medium 95
0.6% 4 Number of Distinct Roll Sequences Dynamic Programming Memoization
Hard 95
0.6% 5 Find Minimum Diameter After Merging Two Trees Tree Depth-First Search Breadth-First Search Graph Theory
Hard 95
0.6% 6 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 89
0.7% 7 Maximum Score with Co-Prime Element Array Hash Table Math Combinatorics Enumeration Number Theory
Hard 89
0.3% 8 Number of Islands Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 86
0.6% 9 Generate Parentheses String Dynamic Programming Backtracking
Medium 82
0.8% 10 String Compression Two Pointers String
Medium 82
0.6% 11 Valid Parentheses String Stack
Easy 77
0.4% 12 Longest Repeating Character Replacement Hash Table String Sliding Window
Medium 77
0.6% 13 Container With Most Water Array Two Pointers Greedy
Medium 71
0.6% 14 First Missing Positive Array Hash Table
Hard 71
0.4% 15 Asteroid Collision Array Stack Simulation
Medium 71
0.5% 16 Sliding Window Maximum Array Queue Sliding Window Heap (Priority Queue) Monotonic Queue
Hard 71
0.5% 17 Pacific Atlantic Water Flow Array Depth-First Search Breadth-First Search Matrix
Medium 71
0.6% 18 Best Time to Buy and Sell Stock II Array Dynamic Programming Greedy
Medium 71
0.7% 19 Two Sum Array Hash Table
Easy 63
0.6% 20 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 63
0.4% 21 Group Anagrams Array Hash Table String Sorting
Medium 63
0.7% 22 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 63
0.5% 23 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 63
0.6% 24 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 63
0.7% 25 Move Zeroes Array Two Pointers
Easy 63
0.6% 26 Number of Visible People in a Queue Array Stack Monotonic Stack
Hard 63
0.7% 27 Coin Change Array Dynamic Programming Breadth-First Search
Medium 63
0.5% 28 Rotting Oranges Array Breadth-First Search Matrix
Medium 63
0.6% 29 Reverse Words in a String II Two Pointers String
Medium 63
0.6% 30 LFU Cache Hash Table Linked List Design Doubly-Linked List
Hard 63
0.5% 31 Set Matrix Zeroes Array Hash Table Matrix
Medium 63
0.6% 32 Check if a Parentheses String Can Be Valid String Stack Greedy
Medium 63
0.5% 33 Minimum Number of Swaps to Make the String Balanced Two Pointers String Stack Greedy
Medium 63
0.8% 34 Jump Game II Array Dynamic Programming Greedy
Medium 63
0.4% 35 Merge Two Sorted Lists Linked List Recursion
Easy 63
0.7% 36 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 53
0.5% 37 Zigzag Conversion String
Medium 53
0.5% 38 Merge Intervals Array Sorting
Medium 53
0.5% 39 Vowels of All Substrings Math String Dynamic Programming Combinatorics
Medium 53
0.6% 40 Maximum Product Subarray Array Dynamic Programming
Medium 53
0.4% 41 Largest Number Array String Greedy Sorting
Medium 53
0.4% 42 Reverse Linked List Linked List Recursion
Easy 53
0.8% 43 Daily Temperatures Array Stack Monotonic Stack
Medium 53
0.7% 44 Minimum One Bit Operations to Make Integers Zero Math Dynamic Programming Bit Manipulation Recursion Memoization
Hard 53
0.8% 45 Pow(x, n) Math Recursion
Medium 53
0.4% 46 Amount of Time for Binary Tree to Be Infected Hash Table Tree Depth-First Search Breadth-First Search Binary Tree
Medium 53
0.7% 47 Time Needed to Rearrange a Binary String String Dynamic Programming Simulation
Medium 53
0.5% 48 Binary Tree Right Side View Tree Depth-First Search Breadth-First Search Binary Tree
Medium 53
0.7% 49 Letter Combinations of a Phone Number Hash Table String Backtracking
Medium 53
0.7% 50 Palindrome Linked List Linked List Two Pointers Stack Recursion
Easy 53
0.6% 51 4Sum Array Two Pointers Sorting
Medium 53
0.4% 52 Number of Distinct Islands Array Hash Table Depth-First Search Breadth-First Search Union-Find Sorting Matrix Hash Function
Medium 53
0.6% 53 Next Permutation Array Two Pointers
Medium 53
0.5% 54 Gas Station Array Greedy
Medium 53
0.5% 55 Find Peak Element Array Binary Search
Medium 53
0.5% 56 Target Sum Array Dynamic Programming Backtracking
Medium 53
0.5% 57 Single Element in a Sorted Array Array Binary Search
Medium 53
0.6% 58 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 53
0.7% 59 Subarrays with K Different Integers Array Hash Table Sliding Window Counting
Hard 53
0.7% 60 House Robber II Array Dynamic Programming
Medium 53
0.5% 61 Maximum Profit From Trading Stocks Array Dynamic Programming
Medium 53
0.5% 62 Subarray Sum Equals K Array Hash Table Prefix Sum
Medium 53
0.5% 63 Next Greater Element II Array Stack Monotonic Stack
Medium 53
0.7% 64 Word Ladder Hash Table String Breadth-First Search
Hard 53
0.5% 65 Simplify Path String Stack
Medium 53
0.5% 66 Fruit Into Baskets Array Hash Table Sliding Window
Medium 53
0.5% 67 Longest Common Subsequence String Dynamic Programming
Medium 53
0.6% 68 Combination Sum Array Backtracking
Medium 53
0.8% 69 Critical Connections in a Network Depth-First Search Graph Theory Biconnected Component
Hard 53
0.6% 70 Reverse Words in a String Two Pointers String
Medium 53
0.6% 71 Sort Colors Array Two Pointers Sorting
Medium 53
0.7%