1 Max Stack Linked List Stack Design Doubly-Linked List Ordered Set
Hard 100
45.5% 2 Nested List Weight Sum II Stack Depth-First Search Breadth-First Search
Medium 95
65.6% 3 All O`one Data Structure Hash Table Linked List Design Doubly-Linked List
Hard 94
44.1% 4 Word Ladder Hash Table String Breadth-First Search
Hard 79
42.8% 5 Find the Celebrity Two Pointers Graph Interactive
Medium 79
48.4% 6 Nested List Weight Sum Depth-First Search Breadth-First Search
Medium 78
85.5% 7 Shortest Word Distance II Array Hash Table Two Pointers String Design
Medium 77
62.1% 8 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 77
52.1% 9 Find Leaves of Binary Tree Tree Depth-First Search Binary Tree
Medium 77
81.1% 10 Valid Parentheses String Stack
Easy 77
42.3% 11 Number of Islands Array Depth-First Search Breadth-First Search Union Find Matrix
Medium 76
62.3% 12 Maximum Product Subarray Array Dynamic Programming
Medium 73
34.9% 13 Can Place Flowers Array Greedy
Easy 72
28.9% 14 Search in Rotated Sorted Array Array Binary Search
Medium 71
42.8% 15 Pow(x, n) Math Recursion
Medium 71
37.0% 16 Binary Tree Upside Down Tree Depth-First Search Binary Tree
Medium 69
64.5% 17 Insert Delete GetRandom O(1) Array Hash Table Math Design Randomized
Medium 69
55.0% 18 Partition to K Equal Sum Subsets Array Dynamic Programming Backtracking Bit Manipulation Memoization Bitmask
Medium 69
38.1% 19 Find First and Last Position of Element in Sorted Array Array Binary Search
Medium 68
46.8% 20 Paint House Array Dynamic Programming
Medium 68
63.7% 21 Serialize and Deserialize Binary Tree String Tree Depth-First Search Breadth-First Search Design Binary Tree
Hard 66
59.0% 22 Minimum Window Substring Hash Table String Sliding Window
Hard 65
45.4% 23 Maximum Depth of Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 64
77.1% 24 Factor Combinations Backtracking
Medium 64
50.2% 25 Shortest Word Distance Array String
Easy 64
65.9% 26 Exclusive Time of Functions Array Stack
Medium 64
64.8% 27 Lowest Common Ancestor of a Binary Tree Tree Depth-First Search Binary Tree
Medium 63
66.8% 28 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 63
68.0% 29 Letter Combinations of a Phone Number Hash Table String Backtracking
Medium 63
63.9% 30 Lowest Common Ancestor of a Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 62
68.3% 31 Isomorphic Strings Hash Table String
Easy 62
46.9% 32 Symmetric Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 61
59.3% 33 Sort Transformed Array Array Math Two Pointers Sorting
Medium 61
57.1% 34 Merge Intervals Array Sorting
Medium 61
49.4% 35 Count Integers in Intervals Design Segment Tree Ordered Set
Hard 60
34.2% 36 Valid Perfect Square Math Binary Search
Easy 60
44.2% 37 Valid Number String
Hard 60
21.6% 38 Kth Smallest Product of Two Sorted Arrays Array Binary Search
Hard 60
30.9% 39 Max Points on a Line Array Hash Table Math Geometry
Hard 59
29.0% 40 Second Minimum Node In a Binary Tree Tree Depth-First Search Binary Tree
Easy 59
45.3% 41 Closest Binary Search Tree Value II Two Pointers Stack Tree Depth-First Search Binary Search Tree Heap (Priority Queue) Binary Tree
Hard 59
60.3% 42 House Robber Array Dynamic Programming
Medium 58
52.3% 43 Evaluate Reverse Polish Notation Array Math Stack
Medium 58
55.0% 44 Repeated DNA Sequences Hash Table String Bit Manipulation Sliding Window Rolling Hash Hash Function
Medium 58
51.3% 45 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 56
45.2% 46 Binary Tree Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 56
70.6% 47 Can I Win Math Dynamic Programming Bit Manipulation Memoization Game Theory Bitmask
Medium 56
30.4% 48 Longest Palindromic Subsequence String Dynamic Programming
Medium 56
64.1% 49 Permutations II Array Backtracking Sorting
Medium 55
61.6% 50 Merge Two Sorted Lists Linked List Recursion
Easy 55
66.8% 51 Flatten Nested List Iterator Stack Tree Depth-First Search Design Queue Iterator
Medium 55
65.2% 52 Shortest Word Distance III Array String
Medium 55
59.1% 53 Permutations Array Backtracking
Medium 55
80.7% 54 Palindromic Substrings Two Pointers String Dynamic Programming
Medium 53
71.7% 55 Sparse Matrix Multiplication Array Hash Table Matrix
Medium 53
68.9% 56 Find K Pairs with Smallest Sums Array Heap (Priority Queue)
Medium 53
40.7% 57 Two Sum Array Hash Table
Easy 53
55.8% 58 Binary Tree Zigzag Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 53
61.7% 59 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 53
56.8% 60 Product of Array Except Self Array Prefix Sum
Medium 52
67.8% 61 Text Justification Array String Simulation
Hard 52
48.1% 62 Find K Closest Elements Array Two Pointers Binary Search Sliding Window Sorting Heap (Priority Queue)
Medium 50
48.7% 63 Sum of Square Numbers Math Two Pointers Binary Search
Medium 50
36.5% 64 Time to Cross a Bridge Array Heap (Priority Queue) Simulation
Hard 50
43.5% 65 Maximize Total Tastiness of Purchased Fruits Array Dynamic Programming
Medium 50
64.5% 66 Find Largest Value in Each Tree Row Tree Depth-First Search Breadth-First Search Binary Tree
Medium 50
66.3% 67 Maximum Number of Non-overlapping Palindrome Substrings Two Pointers String Dynamic Programming Greedy
Hard 50
41.6% 68 Insert Interval Array
Medium 50
43.5% 69 Minimum Deletions to Make Array Divisible Array Math Sorting Heap (Priority Queue) Number Theory
Hard 50
57.7% 70 Insert Delete GetRandom O(1) - Duplicates allowed Array Hash Table Math Design Randomized
Hard 50
35.8% 71 Two Sum III - Data structure design Array Hash Table Two Pointers Design Data Stream
Easy 50
38.7% 72 Create Binary Tree From Descriptions Array Hash Table Tree Binary Tree
Medium 50
81.6% 73 Binary Search Tree Iterator Stack Tree Design Binary Search Tree Binary Tree Iterator
Medium 50
74.9% 74 Max Area of Island Array Depth-First Search Breadth-First Search Union Find Matrix
Medium 48
73.2% 75 Edit Distance String Dynamic Programming
Medium 46
58.8% 76 Rotate List Linked List Two Pointers
Medium 46
39.9% 77 Graph Valid Tree Depth-First Search Breadth-First Search Union Find Graph
Medium 46
49.3% 78 Valid Triangle Number Array Two Pointers Binary Search Greedy Sorting
Medium 46
52.3% 79 Number of Connected Components in an Undirected Graph Depth-First Search Breadth-First Search Union Find Graph
Medium 43
64.2% 80 Min Stack Stack Design
Medium 43
56.4% 81 Shuffle an Array Array Math Design Randomized
Medium 41
59.0% 82 Word Ladder II Hash Table String Backtracking Breadth-First Search
Hard 41
27.2% 83 Combination Sum Array Backtracking
Medium 37
74.7% 84 Merge Sorted Array Array Two Pointers Sorting
Easy 37
52.9% 85 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 37
35.8% 86 Integer to Roman Hash Table Math String
Medium 33
68.6% 87 Intersection of Two Arrays Array Hash Table Two Pointers Binary Search Sorting
Easy 33
76.5% 88 Fizz Buzz Math String Simulation
Easy 33
74.4% 89 Diameter of Binary Tree Tree Depth-First Search Binary Tree
Easy 28
63.6% 90 Same Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 28
65.1% 91 House Robber IV Array Binary Search Dynamic Programming Greedy
Medium 28
65.2% 92 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 28
36.9% 93 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 28
43.8% 94 House Robber II Array Dynamic Programming
Medium 28
43.6% 95 Next Permutation Array Two Pointers
Medium 21
43.1% 96 Reorder List Linked List Two Pointers Stack Recursion
Medium 21
62.5% 97 Minimum Time to Type Word Using Special Typewriter String Greedy
Easy 21
77.7% 98 Design Add and Search Words Data Structure String Depth-First Search Design Trie
Medium 21
47.1% 99 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 21
55.3% 100 Validate Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 21
34.4%