1 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 100
0.5% 2 Remove One Element to Make the Array Strictly Increasing Array
Easy 100
0.3% 3 Alternating Digit Sum Math
Easy 96
0.7% 4 Partition Equal Subset Sum Array Dynamic Programming
Medium 93
0.5% 5 Subtree of Another Tree Tree Depth-First Search String Matching Binary Tree Hash Function
Easy 93
0.5% 6 Minimum Window Subsequence String Dynamic Programming Sliding Window
Hard 93
0.4% 7 Binary Gap Bit Manipulation
Easy 93
0.7% 8 Design Skiplist Linked List Design
Hard 93
0.6% 9 Minimize Maximum Pair Sum in Array Array Two Pointers Greedy Sorting
Medium 93
0.8% 10 Two Sum Array Hash Table
Easy 87
0.6% 11 Spiral Matrix Array Matrix Simulation
Medium 87
0.6% 12 Number of Islands Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 80
0.6% 13 Open the Lock Array Hash Table String Breadth-First Search
Medium 80
0.6% 14 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 80
0.7% 15 Word Ladder Hash Table String Breadth-First Search
Hard 75
0.5% 16 Binary Tree Cameras Dynamic Programming Tree Depth-First Search Binary Tree
Hard 75
0.5% 17 Pow(x, n) Math Recursion
Medium 75
0.4% 18 Set Matrix Zeroes Array Hash Table Matrix
Medium 75
0.6% 19 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 69
0.4% 20 Valid Parentheses String Stack
Easy 69
0.4% 21 Group Anagrams Array Hash Table String Sorting
Medium 69
0.7% 22 Valid Palindrome II Two Pointers String Greedy
Easy 69
0.4% 23 Course Schedule Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 69
0.5% 24 Matchsticks to Square Array Dynamic Programming Backtracking Bit Manipulation Bitmask
Medium 69
0.4% 25 Time Based Key-Value Store Hash Table String Binary Search Design
Medium 69
0.5% 26 Sort Array By Parity Array Two Pointers Sorting
Easy 69
0.8% 27 Merge Intervals Array Sorting
Medium 69
0.5% 28 Reverse Pairs Array Binary Search Divide and Conquer Binary Indexed Tree Segment Tree Merge Sort Ordered Set
Hard 69
0.3% 29 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 62
0.7% 30 Reconstruct Itinerary Array String Depth-First Search Graph Theory Sorting Heap (Priority Queue) Eulerian Circuit
Hard 62
0.4% 31 Rotting Oranges Array Breadth-First Search Matrix
Medium 62
0.6% 32 Sort Colors Array Two Pointers Sorting
Medium 62
0.7% 33 Shortest Unsorted Continuous Subarray Array Two Pointers Stack Greedy Sorting Monotonic Stack
Medium 62
0.4% 34 Interleaving String String Dynamic Programming
Medium 62
0.4% 35 Maximal Square Array Dynamic Programming Matrix
Medium 62
0.5% 36 Jump Game II Array Dynamic Programming Greedy
Medium 62
0.4% 37 Restore the Array From Adjacent Pairs Array Hash Table Depth-First Search
Medium 62
0.8% 38 Word Search Array String Backtracking Depth-First Search Matrix
Medium 62
0.5% 39 3Sum Array Two Pointers Sorting
Medium 62
0.4% 40 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 52
0.4% 41 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 52
0.6% 42 Best Time to Buy and Sell Stock II Array Dynamic Programming Greedy
Medium 52
0.7% 43 Reorganize String Hash Table String Greedy Sorting Heap (Priority Queue) Counting
Medium 52
0.6% 44 Design a Stack With Increment Operation Array Stack Design
Medium 52
0.8% 45 Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit Array Queue Sliding Window Heap (Priority Queue) Ordered Set Monotonic Queue
Medium 52
0.6% 46 Concatenated Words Array String Dynamic Programming Depth-First Search Trie Sorting
Hard 52
0.5% 47 Generate Parentheses String Dynamic Programming Backtracking
Medium 52
0.8% 48 Nearest Exit from Entrance in Maze Array Breadth-First Search Matrix
Medium 52
0.5% 49 Find Peak Element Array Binary Search
Medium 52
0.5% 50 Repeated Substring Pattern String String Matching
Easy 52
0.5% 51 Walls and Gates Array Breadth-First Search Matrix
Medium 52
0.6% 52 Top K Frequent Words Array Hash Table String Trie Sorting Heap (Priority Queue) Bucket Sort Counting
Medium 52
0.6% 53 Palindrome Linked List Linked List Two Pointers Stack Recursion
Easy 52
0.6% 54 Clone Graph Hash Table Depth-First Search Breadth-First Search Graph Theory
Medium 52
0.7% 55 Sudoku Solver Array Hash Table Backtracking Matrix
Hard 52
0.7% 56 Product of Array Except Self Array Prefix Sum
Medium 52
0.7% 57 Decode String String Stack Recursion
Medium 52
0.6% 58 Find Median from Data Stream Two Pointers Design Sorting Heap (Priority Queue) Data Stream
Hard 52
0.5% 59 Block Placement Queries Array Binary Search Binary Indexed Tree Segment Tree Ordered Set
Hard 52
0.4% 60 Alternating Groups II Array Sliding Window
Medium 52
0.6% 61 Alien Dictionary Array String Depth-First Search Breadth-First Search Graph Theory Topological Sort
Hard 52
0.4% 62 Substring with Concatenation of All Words Hash Table String Sliding Window
Hard 52
0.3%