1 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 100
0.5% 2 Remove Duplicate Letters String Stack Greedy Monotonic Stack
Medium 87
0.5% 3 Smallest Subsequence of Distinct Characters String Stack Greedy Monotonic Stack
Medium 87
0.6% 4 First Day Where You Have Been in All the Rooms Array Dynamic Programming
Medium 85
0.4% 5 Combination Sum Array Backtracking
Medium 77
0.8% 6 Number of Islands Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 77
0.6% 7 Course Schedule Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 77
0.5% 8 Merge Intervals Array Sorting
Medium 69
0.5% 9 House Robber Array Dynamic Programming
Medium 69
0.5% 10 Basic Calculator II Math String Stack
Medium 69
0.5% 11 Maximal Square Array Dynamic Programming Matrix
Medium 69
0.5% 12 Shortest Bridge Array Depth-First Search Breadth-First Search Matrix
Medium 69
0.6% 13 Two Sum Array Hash Table
Easy 64
0.6% 14 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 64
0.7% 15 Regular Expression Matching String Dynamic Programming Recursion
Hard 64
0.3% 16 Design Memory Allocator Array Hash Table Design Simulation
Medium 64
0.5% 17 Word Ladder Hash Table String Breadth-First Search
Hard 64
0.5% 18 Search in Rotated Sorted Array Array Binary Search
Medium 57
0.5% 19 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 57
0.7% 20 Decode String String Stack Recursion
Medium 57
0.6% 21 Combination Sum II Array Backtracking
Medium 57
0.6% 22 Rotting Oranges Array Breadth-First Search Matrix
Medium 57
0.6% 23 Longest Common Subsequence String Dynamic Programming
Medium 57
0.6% 24 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 57
0.6% 25 Add Two Numbers Linked List Math Recursion
Medium 57
0.5% 26 Basic Calculator Math String Stack Recursion
Hard 57
0.5% 27 Maximum Width of Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Medium 57
0.5% 28 Multiply Strings Math String Simulation
Medium 57
0.4% 29 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 57
0.5% 30 Accounts Merge Array Hash Table String Depth-First Search Breadth-First Search Union-Find Sorting
Medium 57
0.6% 31 Restore IP Addresses String Backtracking
Medium 57
0.6% 32 Longest Increasing Subsequence Array Binary Search Dynamic Programming
Medium 57
0.6% 33 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 48
0.4% 34 Sort List Linked List Two Pointers Divide and Conquer Sorting Merge Sort
Medium 48
0.6% 35 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 48
0.7% 36 Shortest Distance from All Buildings Array Breadth-First Search Matrix
Hard 48
0.4% 37 Number of Good Leaf Nodes Pairs Tree Depth-First Search Binary Tree
Medium 48
0.7% 38 Climbing Stairs Math Dynamic Programming Memoization
Easy 48
0.5% 39 Insert Delete GetRandom O(1) Array Hash Table Math Design Randomized
Medium 48
0.6% 40 Minimum Area Rectangle Array Hash Table Math Geometry Sorting
Medium 48
0.6% 41 Trapping Rain Water II Array Breadth-First Search Heap (Priority Queue) Matrix
Hard 48
0.6% 42 Subarray Sum Equals K Array Hash Table Prefix Sum
Medium 48
0.5% 43 Subsets Array Backtracking Bit Manipulation
Medium 48
0.8% 44 Longest Repeating Character Replacement Hash Table String Sliding Window
Medium 48
0.6% 45 Remove Zero Sum Consecutive Nodes from Linked List Hash Table Linked List
Medium 48
0.5% 46 Remove K Digits String Stack Greedy Monotonic Stack
Medium 48
0.4% 47 Clone Graph Hash Table Depth-First Search Breadth-First Search Graph Theory
Medium 48
0.7% 48 Reverse Linked List II Linked List
Medium 48
0.5% 49 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 48
0.4% 50 Minimum Swaps to Group All 1's Together II Array Sliding Window
Medium 48
0.7% 51 Find Peak Element Array Binary Search
Medium 48
0.5% 52 Valid Parentheses String Stack
Easy 48
0.4% 53 Find the Length of the Longest Common Prefix Array Hash Table String Trie
Medium 48
0.6% 54 Product of the Last K Numbers Array Math Design Data Stream Prefix Sum
Medium 48
0.6% 55 Jump Game Array Dynamic Programming Greedy
Medium 48
0.4% 56 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 48
0.6% 57 Text Justification Array String Simulation
Hard 48
0.5% 58 Delete Node in a BST Tree Binary Search Tree Binary Tree
Medium 48
0.5% 59 Binary Tree Zigzag Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 48
0.6% 60 Single Element in a Sorted Array Array Binary Search
Medium 48
0.6% 61 3Sum Closest Array Two Pointers Sorting
Medium 48
0.5% 62 Linked List Cycle II Hash Table Linked List Two Pointers
Medium 48
0.6% 63 Sliding Window Maximum Array Queue Sliding Window Heap (Priority Queue) Monotonic Queue
Hard 48
0.5% 64 Unique Paths Math Dynamic Programming Combinatorics
Medium 48
0.7%