1 Two Sum Array Hash Table
Easy 100
55.8% 2 Merge Sorted Array Array Two Pointers Sorting
Easy 84
52.9% 3 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 79
36.9% 4 Add Two Numbers Linked List Math Recursion
Medium 78
46.2% 5 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 76
35.8% 6 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 76
65.1% 7 Merge Intervals Array Sorting
Medium 74
49.4% 8 Valid Parentheses String Stack
Easy 73
42.3% 9 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 73
43.8% 10 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 73
52.1% 11 3Sum Array Two Pointers Sorting
Medium 73
37.1% 12 Group Anagrams Array Hash Table String Sorting
Medium 70
70.9% 13 Search in Rotated Sorted Array Array Binary Search
Medium 69
42.8% 14 Reverse Nodes in k-Group Linked List Recursion
Hard 69
63.0% 15 Merge Two Sorted Lists Linked List Recursion
Easy 69
66.8% 16 Spiral Matrix Array Matrix Simulation
Medium 68
53.9% 17 Roman to Integer Hash Table Math String
Easy 68
64.9% 18 Climbing Stairs Math Dynamic Programming Memoization
Easy 68
53.5% 19 Rotate Image Array Math Matrix
Medium 68
77.9% 20 Container With Most Water Array Two Pointers Greedy
Medium 68
57.8% 21 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 68
56.8% 22 Palindrome Number Math
Easy 68
59.2% 23 Sort Colors Array Two Pointers Sorting
Medium 66
67.6% 24 Longest Common Prefix String Trie
Easy 66
45.5% 25 Remove Duplicates from Sorted Array Array Two Pointers
Easy 65
60.4% 26 Set Matrix Zeroes Array Hash Table Matrix
Medium 63
60.7% 27 Letter Combinations of a Phone Number Hash Table String Backtracking
Medium 63
63.9% 28 Reverse Integer Math
Medium 63
30.3% 29 Word Search Array String Backtracking Depth-First Search Matrix
Medium 61
45.3% 30 Generate Parentheses String Dynamic Programming Backtracking
Medium 60
77.1% 31 Jump Game Array Dynamic Programming Greedy
Medium 59
39.5% 32 Next Permutation Array Two Pointers
Medium 59
43.1% 33 Remove Element Array Two Pointers
Easy 58
60.0% 34 Minimum Path Sum Array Dynamic Programming Matrix
Medium 58
66.5% 35 Binary Tree Zigzag Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 58
61.7% 36 String to Integer (atoi) String
Medium 56
19.2% 37 Validate Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 56
34.4% 38 First Missing Positive Array Hash Table
Hard 55
41.1% 39 Find the Index of the First Occurrence in a String Two Pointers String String Matching
Easy 55
45.0% 40 Combination Sum Array Backtracking
Medium 55
74.7% 41 Find First and Last Position of Element in Sorted Array Array Binary Search
Medium 55
46.8% 42 Largest Rectangle in Histogram Array Stack Monotonic Stack
Hard 55
47.4% 43 Jump Game II Array Dynamic Programming Greedy
Medium 54
41.5% 44 Permutations Array Backtracking
Medium 54
80.7% 45 Unique Paths Math Dynamic Programming Combinatorics
Medium 53
65.8% 46 Swap Nodes in Pairs Linked List Recursion
Medium 53
67.2% 47 4Sum Array Two Pointers Sorting
Medium 52
38.2% 48 Search Insert Position Array Binary Search
Easy 52
49.0% 49 Pow(x, n) Math Recursion
Medium 52
37.0% 50 Integer to Roman Hash Table Math String
Medium 52
68.6% 51 Subsets Array Backtracking Bit Manipulation
Medium 52
80.9% 52 Regular Expression Matching String Dynamic Programming Recursion
Hard 52
29.3% 53 Search a 2D Matrix Array Binary Search Matrix
Medium 51
52.3% 54 Binary Tree Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 51
70.6% 55 N-Queens Array Backtracking
Hard 51
72.8% 56 Valid Sudoku Array Hash Table Matrix
Medium 50
62.3% 57 Binary Tree Inorder Traversal Stack Tree Depth-First Search Binary Tree
Easy 50
78.6% 58 Divide Two Integers Math Bit Manipulation
Medium 50
18.4% 59 Remove Nth Node From End of List Linked List Two Pointers
Medium 50
49.0% 60 Edit Distance String Dynamic Programming
Medium 50
58.8% 61 Simplify Path String Stack
Medium 50
47.9% 62 Restore IP Addresses String Backtracking
Medium 49
53.2% 63 Sudoku Solver Array Hash Table Backtracking Matrix
Hard 49
63.9% 64 Longest Valid Parentheses String Dynamic Programming Stack
Hard 47
36.3% 65 Decode Ways String Dynamic Programming
Medium 46
36.5% 66 Maximal Rectangle Array Dynamic Programming Stack Matrix Monotonic Stack
Hard 45
53.7% 67 Sqrt(x) Math Binary Search
Easy 45
40.4% 68 Reverse Linked List II Linked List
Medium 44
49.6% 69 Permutations II Array Backtracking Sorting
Medium 44
61.6% 70 Zigzag Conversion String
Medium 44
51.6% 71 Plus One Array Math
Easy 43
47.5% 72 Symmetric Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 43
59.3% 73 Add Binary Math String Bit Manipulation Simulation
Easy 41
55.7% 74 Minimum Window Substring Hash Table String Sliding Window
Hard 41
45.4% 75 Search in Rotated Sorted Array II Array Binary Search
Medium 39
38.9% 76 Wildcard Matching String Dynamic Programming Greedy Recursion
Hard 39
29.9% 77 Remove Duplicates from Sorted List Linked List
Easy 39
54.9% 78 Remove Duplicates from Sorted Array II Array Two Pointers
Medium 38
62.9% 79 Insert Interval Array
Medium 38
43.5% 80 Combination Sum II Array Backtracking
Medium 38
57.7% 81 Multiply Strings Math String Simulation
Medium 38
42.3% 82 Text Justification Array String Simulation
Hard 38
48.1% 83 Spiral Matrix II Array Matrix Simulation
Medium 38
73.4% 84 Length of Last Word String
Easy 38
56.3% 85 Recover Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 36
56.3% 86 Interleaving String String Dynamic Programming
Medium 36
42.2% 87 Same Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 36
65.1% 88 Maximum Depth of Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 36
77.1% 89 Subsets II Array Backtracking Bit Manipulation
Medium 36
59.5% 90 Rotate List Linked List Two Pointers
Medium 36
39.9% 91 Remove Duplicates from Sorted List II Linked List Two Pointers
Medium 35
49.9% 92 Combinations Backtracking
Medium 31
72.9% 93 Count and Say String
Medium 31
60.5% 94 3Sum Closest Array Two Pointers Sorting
Medium 31
46.9% 95 Substring with Concatenation of All Words Hash Table String Sliding Window
Hard 27
33.0% 96 Partition List Linked List Two Pointers
Medium 24
59.0% 97 Unique Paths II Array Dynamic Programming Matrix
Medium 24
43.2% 98 Unique Binary Search Trees Math Dynamic Programming Tree Binary Search Tree Binary Tree
Medium 21
62.4% 99 N-Queens II Backtracking
Hard 21
76.7% 100 Unique Binary Search Trees II Dynamic Programming Backtracking Tree Binary Search Tree Binary Tree
Medium 13
60.4%