1 Merge Sorted Array Array Two Pointers Sorting
Easy 88
52.9% 2 Pow(x, n) Math Recursion
Medium 87
37.0% 3 Simplify Path String Stack
Medium 86
47.9% 4 Merge Intervals Array Sorting
Medium 85
49.4% 5 Two Sum Array Hash Table
Easy 84
55.8% 6 Next Permutation Array Two Pointers
Medium 78
43.1% 7 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 77
56.8% 8 3Sum Array Two Pointers Sorting
Medium 77
37.1% 9 Find First and Last Position of Element in Sorted Array Array Binary Search
Medium 72
46.8% 10 Valid Parentheses String Stack
Easy 71
42.3% 11 Valid Number String
Hard 70
21.6% 12 Minimum Window Substring Hash Table String Sliding Window
Hard 69
45.4% 13 Longest Common Prefix String Trie
Easy 67
45.5% 14 Add Two Numbers Linked List Math Recursion
Medium 65
46.2% 15 Letter Combinations of a Phone Number Hash Table String Backtracking
Medium 64
63.9% 16 Subsets Array Backtracking Bit Manipulation
Medium 64
80.9% 17 Remove Nth Node From End of List Linked List Two Pointers
Medium 64
49.0% 18 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 63
36.9% 19 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 61
65.1% 20 String to Integer (atoi) String
Medium 60
19.2% 21 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 59
35.8% 22 Remove Duplicates from Sorted Array Array Two Pointers
Easy 59
60.4% 23 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 58
43.8% 24 Palindrome Number Math
Easy 57
59.2% 25 Search in Rotated Sorted Array Array Binary Search
Medium 57
42.8% 26 Roman to Integer Hash Table Math String
Easy 56
64.9% 27 Merge Two Sorted Lists Linked List Recursion
Easy 54
66.8% 28 Group Anagrams Array Hash Table String Sorting
Medium 54
70.9% 29 Count and Say String
Medium 53
60.5% 30 Climbing Stairs Math Dynamic Programming Memoization
Easy 53
53.5% 31 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 52
52.1% 32 Container With Most Water Array Two Pointers Greedy
Medium 52
57.8% 33 Set Matrix Zeroes Array Hash Table Matrix
Medium 51
60.7% 34 Sort Colors Array Two Pointers Sorting
Medium 51
67.6% 35 Add Binary Math String Bit Manipulation Simulation
Easy 51
55.7% 36 Multiply Strings Math String Simulation
Medium 50
42.3% 37 Reverse Integer Math
Medium 49
30.3% 38 Word Search Array String Backtracking Depth-First Search Matrix
Medium 48
45.3% 39 Plus One Array Math
Easy 48
47.5% 40 Generate Parentheses String Dynamic Programming Backtracking
Medium 48
77.1% 41 Rotate Image Array Math Matrix
Medium 47
77.9% 42 Spiral Matrix Array Matrix Simulation
Medium 47
53.9% 43 Regular Expression Matching String Dynamic Programming Recursion
Hard 46
29.3% 44 Insert Interval Array
Medium 45
43.5% 45 Find the Index of the First Occurrence in a String Two Pointers String String Matching
Easy 45
45.0% 46 Sqrt(x) Math Binary Search
Easy 44
40.4% 47 Search a 2D Matrix Array Binary Search Matrix
Medium 43
52.3% 48 Binary Tree Zigzag Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 43
61.7% 49 Divide Two Integers Math Bit Manipulation
Medium 43
18.4% 50 Largest Rectangle in Histogram Array Stack Monotonic Stack
Hard 43
47.4% 51 Binary Tree Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 43
70.6% 52 Remove Duplicates from Sorted Array II Array Two Pointers
Medium 42
62.9% 53 Unique Paths Math Dynamic Programming Combinatorics
Medium 42
65.8% 54 Remove Element Array Two Pointers
Easy 42
60.0% 55 Jump Game Array Dynamic Programming Greedy
Medium 42
39.5% 56 Text Justification Array String Simulation
Hard 41
48.1% 57 Validate Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 41
34.4% 58 3Sum Closest Array Two Pointers Sorting
Medium 40
46.9% 59 Decode Ways String Dynamic Programming
Medium 40
36.5% 60 Combination Sum Array Backtracking
Medium 40
74.7% 61 Subsets II Array Backtracking Bit Manipulation
Medium 37
59.5% 62 4Sum Array Two Pointers Sorting
Medium 37
38.2% 63 Maximal Rectangle Array Dynamic Programming Stack Matrix Monotonic Stack
Hard 37
53.7% 64 Valid Sudoku Array Hash Table Matrix
Medium 37
62.3% 65 Permutations Array Backtracking
Medium 36
80.7% 66 Reverse Nodes in k-Group Linked List Recursion
Hard 36
63.0% 67 Zigzag Conversion String
Medium 36
51.6% 68 First Missing Positive Array Hash Table
Hard 35
41.1% 69 Wildcard Matching String Dynamic Programming Greedy Recursion
Hard 35
29.9% 70 Binary Tree Inorder Traversal Stack Tree Depth-First Search Binary Tree
Easy 35
78.6% 71 Minimum Depth of Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 35
50.7% 72 Combination Sum II Array Backtracking
Medium 35
57.7% 73 Unique Paths II Array Dynamic Programming Matrix
Medium 35
43.2% 74 N-Queens Array Backtracking
Hard 34
72.8% 75 Construct Binary Tree from Preorder and Inorder Traversal Array Hash Table Divide and Conquer Tree Binary Tree
Medium 34
66.8% 76 Search Insert Position Array Binary Search
Easy 34
49.0% 77 Jump Game II Array Dynamic Programming Greedy
Medium 34
41.5% 78 Rotate List Linked List Two Pointers
Medium 33
39.9% 79 Search in Rotated Sorted Array II Array Binary Search
Medium 33
38.9% 80 Maximum Depth of Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 32
77.1% 81 Reverse Linked List II Linked List
Medium 32
49.6% 82 Edit Distance String Dynamic Programming
Medium 32
58.8% 83 Length of Last Word String
Easy 32
56.3% 84 Sudoku Solver Array Hash Table Backtracking Matrix
Hard 31
63.9% 85 Symmetric Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 31
59.3% 86 Convert Sorted List to Binary Search Tree Linked List Divide and Conquer Tree Binary Search Tree Binary Tree
Medium 27
64.5% 87 Restore IP Addresses String Backtracking
Medium 27
53.2% 88 Longest Valid Parentheses String Dynamic Programming Stack
Hard 27
36.3% 89 Same Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 26
65.1% 90 Integer to Roman Hash Table Math String
Medium 26
68.6% 91 Swap Nodes in Pairs Linked List Recursion
Medium 26
67.2% 92 Combinations Backtracking
Medium 24
72.9% 93 Convert Sorted Array to Binary Search Tree Array Divide and Conquer Tree Binary Search Tree Binary Tree
Easy 22
74.1% 94 Minimum Path Sum Array Dynamic Programming Matrix
Medium 22
66.5% 95 Balanced Binary Tree Tree Depth-First Search Binary Tree
Easy 22
55.3% 96 Permutations II Array Backtracking Sorting
Medium 18
61.6% 97 Unique Binary Search Trees II Dynamic Programming Backtracking Tree Binary Search Tree Binary Tree
Medium 16
60.4% 98 Substring with Concatenation of All Words Hash Table String Sliding Window
Hard 16
33.0% 99 Spiral Matrix II Array Matrix Simulation
Medium 14
73.4% 100 Binary Tree Level Order Traversal II Tree Breadth-First Search Binary Tree
Medium 8
66.0%