1 Two Sum Array Hash Table
Easy 100
0.6% 2 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 92
0.4% 3 Group Anagrams Array Hash Table String Sorting
Medium 92
0.7% 4 Majority Element Array Hash Table Divide and Conquer Sorting Counting
Easy 92
0.7% 5 Special Binary String String Divide and Conquer Sorting
Hard 92
0.8% 6 Add Two Numbers Linked List Math Recursion
Medium 91
0.5% 7 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 91
0.5% 8 3Sum Array Two Pointers Sorting
Medium 87
0.4% 9 Climbing Stairs Math Dynamic Programming Memoization
Easy 87
0.5% 10 Reverse Linked List Linked List Recursion
Easy 87
0.8% 11 Smallest Range II Array Math Greedy Sorting
Medium 87
0.4% 12 Merge Intervals Array Sorting
Medium 84
0.5% 13 Nim Game Math Brainteaser Game Theory
Easy 84
0.6% 14 Number of Increasing Paths in a Grid Array Dynamic Programming Depth-First Search Breadth-First Search Graph Theory Topological Sort Memoization Matrix
Hard 84
0.6% 15 Divide Intervals Into Minimum Number of Groups Array Two Pointers Greedy Sorting Heap (Priority Queue) Prefix Sum
Medium 84
0.6% 16 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 82
0.5% 17 Tenth Line Shell
Easy 82
0.4% 18 Delete Node in a Linked List Linked List
Medium 82
0.8% 19 Add Digits Math Simulation Number Theory
Easy 82
0.7% 20 Kth Largest Element in a Stream Tree Design Binary Search Tree Heap (Priority Queue) Binary Tree Data Stream
Easy 82
0.6% 21 Preimage Size of Factorial Zeroes Function Math Binary Search
Hard 82
0.5% 22 Number of Subarrays with Bounded Maximum Array Two Pointers
Medium 82
0.6% 23 Smallest Range I Array Math
Easy 82
0.7% 24 Reverse Substrings Between Each Pair of Parentheses String Stack
Medium 82
0.7% 25 Count Ways to Build Rooms in an Ant Colony Array Math Dynamic Programming Tree Depth-First Search Graph Theory Topological Sort Combinatorics
Hard 82
0.5% 26 Plates Between Candles Array String Binary Search Prefix Sum
Medium 82
0.5% 27 Choose Numbers From Two Arrays in Range Array Dynamic Programming
Hard 82
0.5% 28 Minimize XOR Greedy Bit Manipulation
Medium 82
0.6% 29 Merge Operations to Turn Array Into a Palindrome Array Two Pointers Greedy
Medium 82
0.7% 30 Minimizing Array After Replacing Pairs With Their Product Array Dynamic Programming Greedy
Medium 82
0.4% 31 Count Subarrays Where Max Element Appears at Least K Times Array Sliding Window
Medium 82
0.6% 32 Bitwise OR of Adjacent Elements Array Bit Manipulation
Easy 82
0.9% 33 Number of Islands Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 79
0.6% 34 Minimum Window Substring Hash Table String Sliding Window
Hard 76
0.5% 35 Threshold Majority Queries Array Hash Table Binary Search Divide and Conquer Counting Prefix Sum
Hard 76
0.2% 36 Minimum Moves to Equal Array Elements III Array Math
Easy 76
0.8% 37 Integer to Roman Hash Table Math String
Medium 72
0.7% 38 Next Permutation Array Two Pointers
Medium 72
0.5% 39 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 72
0.7% 40 Jump Game Array Dynamic Programming Greedy
Medium 72
0.4% 41 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 72
0.6% 42 Validate IP Address String
Medium 72
0.3% 43 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 68
0.4% 44 Longest Common Prefix Array String Trie
Easy 68
0.5% 45 Valid Parentheses String Stack
Easy 68
0.4% 46 Maximum Product Subarray Array Dynamic Programming
Medium 68
0.4% 47 Sort Array by Increasing Frequency Array Hash Table Sorting
Easy 68
0.8% 48 Spiral Matrix Array Matrix Simulation
Medium 64
0.6% 49 Restore IP Addresses String Backtracking
Medium 64
0.6% 50 Gas Station Array Greedy
Medium 64
0.5% 51 Largest Number Array String Greedy Sorting
Medium 64
0.4% 52 Lowest Common Ancestor of a Binary Tree Tree Depth-First Search Binary Tree
Medium 64
0.7% 53 Coin Change Array Dynamic Programming Breadth-First Search
Medium 64
0.5% 54 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 64
0.7% 55 Koko Eating Bananas Array Binary Search
Medium 64
0.5% 56 Fruit Into Baskets Array Hash Table Sliding Window
Medium 64
0.5% 57 Minimum Processing Time Array Greedy Sorting
Medium 64
0.7% 58 Top K Frequent Words Array Hash Table String Trie Sorting Heap (Priority Queue) Bucket Sort Counting
Medium 64
0.6% 59 String to Integer (atoi) String
Medium 58
0.2% 60 Roman to Integer Hash Table Math String
Easy 58
0.7% 61 Search in Rotated Sorted Array Array Binary Search
Medium 58
0.5% 62 Search a 2D Matrix Array Binary Search Matrix
Medium 58
0.5% 63 Binary Tree Zigzag Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 58
0.6% 64 Remove K Digits String Stack Greedy Monotonic Stack
Medium 58
0.4% 65 Rotting Oranges Array Breadth-First Search Matrix
Medium 58
0.6% 66 Count Pairs Of Similar Strings Array Hash Table String Bit Manipulation Counting
Easy 58
0.7% 67 Shortest Path in a Grid with Obstacles Elimination Array Breadth-First Search Matrix
Hard 58
0.5% 68 Binary Tree Maximum Path Sum Dynamic Programming Tree Depth-First Search Binary Tree
Hard 58
0.4% 69 Reverse Integer Math
Medium 50
0.3% 70 Generate Parentheses String Dynamic Programming Backtracking
Medium 50
0.8% 71 Remove Element Array Two Pointers
Easy 50
0.6% 72 Jump Game II Array Dynamic Programming Greedy
Medium 50
0.4% 73 Rotate Image Array Math Matrix
Medium 50
0.8% 74 N-Queens Array Backtracking
Hard 50
0.8% 75 Binary Tree Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 50
0.7% 76 Construct Binary Tree from Preorder and Inorder Traversal Array Hash Table Divide and Conquer Tree Binary Tree
Medium 50
0.7% 77 Longest Consecutive Sequence Array Hash Table Union-Find
Medium 50
0.5% 78 Single Number Array Bit Manipulation
Easy 50
0.8% 79 House Robber Array Dynamic Programming
Medium 50
0.5% 80 Basic Calculator II Math String Stack
Medium 50
0.5% 81 Product of Array Except Self Array Prefix Sum
Medium 50
0.7% 82 Sliding Window Maximum Array Queue Sliding Window Heap (Priority Queue) Monotonic Queue
Hard 50
0.5% 83 Meeting Rooms II Array Two Pointers Greedy Sorting Heap (Priority Queue) Prefix Sum
Medium 50
0.5% 84 Number of Provinces Depth-First Search Breadth-First Search Union-Find Graph Theory
Medium 50
0.7% 85 Sum of All Subset XOR Totals Array Math Backtracking Bit Manipulation Combinatorics Enumeration
Easy 50
0.9% 86 Amount of Time for Binary Tree to Be Infected Hash Table Tree Depth-First Search Breadth-First Search Binary Tree
Medium 50
0.7% 87 Shopping Offers Array Dynamic Programming Backtracking Bit Manipulation Memoization Bitmask
Medium 50
0.5% 88 Longest Increasing Path in a Matrix Array Dynamic Programming Depth-First Search Breadth-First Search Graph Theory Topological Sort Memoization Matrix
Hard 50
0.6% 89 Unit Conversion I Depth-First Search Breadth-First Search Graph Theory
Medium 50
0.5% 90 Nested List Weight Sum Depth-First Search Breadth-First Search
Medium 50
0.9% 91 Contains Duplicate II Array Hash Table Sliding Window
Easy 50
0.5% 92 Is Subsequence Two Pointers String Dynamic Programming
Easy 50
0.5% 93 Heaters Array Two Pointers Binary Search Sorting
Medium 50
0.4% 94 Minimum Cost For Tickets Array Dynamic Programming
Medium 50
0.7% 95 Game of Life Array Matrix Simulation
Medium 50
0.7% 96 Flatten Nested List Iterator Stack Tree Depth-First Search Design Queue Iterator
Medium 50
0.7% 97 Container With Most Water Array Two Pointers Greedy
Medium 40
0.6% 98 Reverse Nodes in k-Group Linked List Recursion
Hard 40
0.7% 99 Combination Sum II Array Backtracking
Medium 40
0.6% 100 Pow(x, n) Math Recursion
Medium 40
0.4% 101 Largest Rectangle in Histogram Array Stack Monotonic Stack
Hard 40
0.5% 102 Decode Ways String Dynamic Programming
Medium 40
0.4% 103 Valid Palindrome Two Pointers String
Easy 40
0.5% 104 Word Ladder Hash Table String Breadth-First Search
Hard 40
0.5% 105 Surrounded Regions Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 40
0.5% 106 Min Stack Stack Design
Medium 40
0.6% 107 Two Sum II - Input Array Is Sorted Array Two Pointers Binary Search
Medium 40
0.7% 108 Binary Search Tree Iterator Stack Tree Design Binary Search Tree Binary Tree Iterator
Medium 40
0.8% 109 Course Schedule Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 40
0.5% 110 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 40
0.7% 111 Missing Number Array Hash Table Math Binary Search Bit Manipulation Sorting
Easy 40
0.7% 112 Move Zeroes Array Two Pointers
Easy 40
0.6% 113 Pacific Atlantic Water Flow Array Depth-First Search Breadth-First Search Matrix
Medium 40
0.6% 114 Longest Repeating Character Replacement Hash Table String Sliding Window
Medium 40
0.6% 115 Single Element in a Sorted Array Array Binary Search
Medium 40
0.6% 116 01 Matrix Array Dynamic Programming Breadth-First Search Matrix
Medium 40
0.5% 117 Next Greater Element III Math Two Pointers String
Medium 40
0.4% 118 Subarray Sum Equals K Array Hash Table Prefix Sum
Medium 40
0.5% 119 Permutation in String Hash Table Two Pointers String Sliding Window
Medium 40
0.5% 120 Shortest Path to Get All Keys Array Bit Manipulation Breadth-First Search Matrix
Hard 40
0.5% 121 Random Pick with Weight Array Math Binary Search Prefix Sum Randomized
Medium 40
0.5% 122 Squares of a Sorted Array Array Two Pointers Sorting
Easy 40
0.7% 123 Cousins in Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 40
0.6% 124 Search Suggestions System Array String Binary Search Trie Sorting Heap (Priority Queue)
Medium 40
0.7% 125 Customer Who Visited but Did Not Make Any Transactions Database
Easy 40
0.7% 126 To Be Or Not To Be Easy 40
0.6% 127 Minimum Swaps to Group All 1's Together II Array Sliding Window
Medium 40
0.7% 128 Basic Calculator Math String Stack Recursion
Hard 40
0.5% 129 Range Sum Query - Mutable Array Divide and Conquer Design Binary Indexed Tree Segment Tree
Medium 40
0.4% 130 Contiguous Array Array Hash Table Prefix Sum
Medium 40
0.5% 131 Split the Array Array Hash Table Counting
Easy 40
0.6% 132 Design Twitter Hash Table Linked List Design Heap (Priority Queue)
Medium 40
0.4% 133 Increment Submatrices by One Array Matrix Prefix Sum
Medium 40
0.7% 134 Max Consecutive Ones III Array Binary Search Sliding Window Prefix Sum
Medium 40
0.7% 135 Count Complete Tree Nodes Binary Search Bit Manipulation Tree Binary Tree
Easy 40
0.7% 136 Trim a Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 40
0.7% 137 Largest Combination With Bitwise AND Greater Than Zero Array Hash Table Bit Manipulation Counting
Medium 40
0.8% 138 Boundary of Binary Tree Tree Depth-First Search Binary Tree
Medium 40
0.5% 139 Reformat Date String
Easy 40
0.7% 140 Minimum Number of Swaps to Make the String Balanced Two Pointers String Stack Greedy
Medium 40
0.8% 141 Maximum Profit From Trading Stocks Array Dynamic Programming
Medium 40
0.5% 142 Reconstruct Itinerary Array String Depth-First Search Graph Theory Sorting Heap (Priority Queue) Eulerian Circuit
Hard 40
0.4% 143 Find the Difference of Two Arrays Array Hash Table
Easy 40
0.8% 144 Add Binary Math String Bit Manipulation Simulation
Easy 40
0.6% 145 Minimum Number of Days to Make m Bouquets Array Binary Search
Medium 40
0.6% 146 Spiral Matrix II Array Matrix Simulation
Medium 40
0.8% 147 Minimum Number of Taps to Open to Water a Garden Array Dynamic Programming Greedy
Hard 40
0.5% 148 Max Area of Island Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 40
0.7%