TikTok LeetCode Questions
351 questions all-time · 34 easy · 245 medium · 72 hard
| # | Problem | Difficulty | Frequency | Acceptance |
|---|---|---|---|---|
| 1 | LRU Cache Hash Table, Linked List, Design, Doubly-Linked List | Medium | 100 | 0.5% |
| 2 | Number of Islands Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Medium | 99 | 0.6% |
| 3 | Longest Increasing Subsequence Array, Binary Search, Dynamic Programming | Medium | 90 | 0.6% |
| 4 | Longest Substring Without Repeating Characters Hash Table, String, Sliding Window | Medium | 88 | 0.4% |
| 5 | Number of Distinct Islands Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Sorting, Matrix, Hash Function | Medium | 87 | 0.6% |
| 6 | Course Schedule II Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Medium | 87 | 0.6% |
| 7 | Meeting Rooms II Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum | Medium | 87 | 0.5% |
| 8 | Merge Intervals Array, Sorting | Medium | 84 | 0.5% |
| 9 | Trapping Rain Water Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack | Hard | 84 | 0.7% |
| 10 | Course Schedule Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Medium | 84 | 0.5% |
| 11 | Subarray With Elements Greater Than Varying Threshold Array, Stack, Union-Find, Monotonic Stack | Hard | 84 | 0.5% |
| 12 | Text Justification Array, String, Simulation | Hard | 80 | 0.5% |
| 13 | Decode String String, Stack, Recursion | Medium | 78 | 0.6% |
| 14 | Word Search Array, String, Backtracking, Depth-First Search, Matrix | Medium | 77 | 0.5% |
| 15 | Longest Palindromic Substring Two Pointers, String, Dynamic Programming | Medium | 75 | 0.4% |
| 16 | N-Queens Array, Backtracking | Hard | 75 | 0.8% |
| 17 | Minimum Window Substring Hash Table, String, Sliding Window | Hard | 75 | 0.5% |
| 18 | Search in Rotated Sorted Array Array, Binary Search | Medium | 74 | 0.5% |
| 19 | 3Sum Array, Two Pointers, Sorting | Medium | 72 | 0.4% |
| 20 | Top K Frequent Elements Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect | Medium | 72 | 0.7% |
| 21 | Subarray Sum Equals K Array, Hash Table, Prefix Sum | Medium | 72 | 0.5% |
| 22 | Sqrt(x) Math, Binary Search | Easy | 71 | 0.4% |
| 23 | Coin Change Array, Dynamic Programming, Breadth-First Search | Medium | 71 | 0.5% |
| 24 | Minimum Swaps to Group All 1's Together Array, Sliding Window | Medium | 71 | 0.6% |
| 25 | Spiral Matrix Array, Matrix, Simulation | Medium | 70 | 0.6% |
| 26 | Merge k Sorted Lists Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort | Hard | 68 | 0.6% |
| 27 | Best Time to Buy and Sell Stock Array, Dynamic Programming | Easy | 68 | 0.6% |
| 28 | Longest Consecutive Sequence Array, Hash Table, Union-Find | Medium | 68 | 0.5% |
| 29 | Making A Large Island Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Hard | 68 | 0.6% |
| 30 | Maximum Value at a Given Index in a Bounded Array Math, Binary Search, Greedy | Medium | 68 | 0.4% |
| 31 | Valid Parentheses String, Stack | Easy | 67 | 0.4% |
| 32 | House Robber Array, Dynamic Programming | Medium | 67 | 0.5% |
| 33 | Kth Largest Element in an Array Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect | Medium | 67 | 0.7% |
| 34 | Basic Calculator II Math, String, Stack | Medium | 67 | 0.5% |
| 35 | Maximum Swap Math, Greedy | Medium | 67 | 0.5% |
| 36 | Basic Calculator III Math, String, Stack, Recursion | Hard | 67 | 0.5% |
| 37 | Longest Happy String String, Greedy, Heap (Priority Queue) | Medium | 67 | 0.7% |
| 38 | Snapshot Array Array, Hash Table, Binary Search, Design | Medium | 67 | 0.4% |
| 39 | Two Sum Array, Hash Table | Easy | 65 | 0.6% |
| 40 | Word Ladder Hash Table, String, Breadth-First Search | Hard | 65 | 0.5% |
| 41 | Generate Parentheses String, Dynamic Programming, Backtracking | Medium | 63 | 0.8% |
| 42 | Sort Colors Array, Two Pointers, Sorting | Medium | 63 | 0.7% |
| 43 | Count the Hidden Sequences Array, Prefix Sum | Medium | 63 | 0.6% |
| 44 | Longest Increasing Path in a Matrix Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort, Memoization, Matrix | Hard | 63 | 0.6% |
| 45 | Insert Delete GetRandom O(1) Array, Hash Table, Math, Design, Randomized | Medium | 63 | 0.6% |
| 46 | Valid Parenthesis String String, Dynamic Programming, Stack, Greedy | Medium | 63 | 0.4% |
| 47 | Max Area of Island Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Medium | 63 | 0.7% |
| 48 | Design HashMap Array, Hash Table, Linked List, Design, Hash Function | Easy | 63 | 0.7% |
| 49 | Construct Binary Tree from Preorder and Inorder Traversal Array, Hash Table, Divide and Conquer, Tree, Binary Tree | Medium | 61 | 0.7% |
| 50 | Add Strings Math, String, Simulation | Easy | 61 | 0.5% |
| 51 | Meeting Rooms III Array, Hash Table, Sorting, Heap (Priority Queue), Simulation | Hard | 61 | 0.5% |
| 52 | Closest Prime Numbers in Range Math, Number Theory | Medium | 61 | 0.5% |
| 53 | Daily Temperatures Array, Stack, Monotonic Stack | Medium | 61 | 0.7% |
| 54 | Word Search II Array, String, Backtracking, Trie, Matrix | Hard | 61 | 0.4% |
| 55 | Edit Distance String, Dynamic Programming | Medium | 59 | 0.6% |
| 56 | Binary Tree Maximum Path Sum Dynamic Programming, Tree, Depth-First Search, Binary Tree | Hard | 59 | 0.4% |
| 57 | Word Break II Array, Hash Table, String, Dynamic Programming, Backtracking, Trie, Memoization | Hard | 59 | 0.6% |
| 58 | Reorder List Linked List, Two Pointers, Stack, Recursion | Medium | 59 | 0.7% |
| 59 | Serialize and Deserialize Binary Tree String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree | Hard | 59 | 0.6% |
| 60 | Length of the Longest Alphabetical Continuous Substring String | Medium | 59 | 0.6% |
| 61 | Most Popular Video Creator Array, Hash Table, String, Sorting, Heap (Priority Queue) | Medium | 59 | 0.5% |
| 62 | Find the Score of All Prefixes of an Array Array, Prefix Sum | Medium | 59 | 0.7% |
| 63 | Count Complete Subarrays in an Array Array, Hash Table, Sliding Window | Medium | 59 | 0.8% |
| 64 | Minimum Moves to Pick K Ones Array, Greedy, Sliding Window, Prefix Sum | Hard | 59 | 0.2% |
| 65 | Incremental Memory Leak Math, Simulation | Medium | 59 | 0.7% |
| 66 | Minimum Operations to Make Character Frequencies Equal Hash Table, String, Dynamic Programming, Counting, Enumeration | Hard | 59 | 0.3% |
| 67 | Minimum Cost Good Caption String, Dynamic Programming | Hard | 59 | 0.2% |
| 68 | Lexicographically Smallest Generated String String, Greedy, String Matching | Hard | 59 | 0.5% |
| 69 | Combination Sum Array, Backtracking | Medium | 57 | 0.8% |
| 70 | Climbing Stairs Math, Dynamic Programming, Memoization | Easy | 57 | 0.5% |
| 71 | Simplify Path String, Stack | Medium | 57 | 0.5% |
| 72 | Binary Tree Right Side View Tree, Depth-First Search, Breadth-First Search, Binary Tree | Medium | 57 | 0.7% |
| 73 | Reverse Linked List Linked List, Recursion | Easy | 57 | 0.8% |
| 74 | Basic Calculator Math, String, Stack, Recursion | Hard | 57 | 0.5% |
| 75 | Find Median from Data Stream Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream | Hard | 57 | 0.5% |
| 76 | Bus Routes Array, Hash Table, Breadth-First Search | Hard | 57 | 0.5% |
| 77 | Shortest Path in a Grid with Obstacles Elimination Array, Breadth-First Search, Matrix | Hard | 57 | 0.5% |
| 78 | Container With Most Water Array, Two Pointers, Greedy | Medium | 54 | 0.6% |
| 79 | Find First and Last Position of Element in Sorted Array Array, Binary Search | Medium | 54 | 0.5% |
| 80 | Group Anagrams Array, Hash Table, String, Sorting | Medium | 54 | 0.7% |
| 81 | Jump Game Array, Dynamic Programming, Greedy | Medium | 54 | 0.4% |
| 82 | Subsets Array, Backtracking, Bit Manipulation | Medium | 54 | 0.8% |
| 83 | Word Break Array, Hash Table, String, Dynamic Programming, Trie, Memoization | Medium | 54 | 0.5% |
| 84 | Find Peak Element Array, Binary Search | Medium | 54 | 0.5% |
| 85 | Lowest Common Ancestor of a Binary Tree Tree, Depth-First Search, Binary Tree | Medium | 54 | 0.7% |
| 86 | Sliding Window Maximum Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue | Hard | 54 | 0.5% |
| 87 | Longest Substring with At Least K Repeating Characters Hash Table, String, Divide and Conquer, Sliding Window | Medium | 54 | 0.5% |
| 88 | Pacific Atlantic Water Flow Array, Depth-First Search, Breadth-First Search, Matrix | Medium | 54 | 0.6% |
| 89 | Asteroid Collision Array, Stack, Simulation | Medium | 54 | 0.5% |
| 90 | Koko Eating Bananas Array, Binary Search | Medium | 54 | 0.5% |
| 91 | Possible Bipartition Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Medium | 54 | 0.5% |
| 92 | Rotting Oranges Array, Breadth-First Search, Matrix | Medium | 54 | 0.6% |
| 93 | Shortest Bridge Array, Depth-First Search, Breadth-First Search, Matrix | Medium | 54 | 0.6% |
| 94 | Design Add and Search Words Data Structure String, Depth-First Search, Design, Trie | Medium | 54 | 0.5% |
| 95 | Regular Expression Matching String, Dynamic Programming, Recursion | Hard | 51 | 0.3% |
| 96 | Longest Common Prefix Array, String, Trie | Easy | 51 | 0.5% |
| 97 | Reverse Nodes in k-Group Linked List, Recursion | Hard | 51 | 0.7% |
| 98 | Jump Game II Array, Dynamic Programming, Greedy | Medium | 51 | 0.4% |
| 99 | Permutations Array, Backtracking | Medium | 51 | 0.8% |
| 100 | Maximum Subarray Array, Divide and Conquer, Dynamic Programming | Medium | 51 | 0.5% |
| 101 | Restore IP Addresses String, Backtracking | Medium | 51 | 0.6% |
| 102 | Minimum Size Subarray Sum Array, Binary Search, Sliding Window, Prefix Sum | Medium | 51 | 0.5% |
| 103 | Meeting Rooms Array, Sorting | Easy | 51 | 0.6% |
| 104 | Alien Dictionary Array, String, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Hard | 51 | 0.4% |
| 105 | Remove Duplicate Letters String, Stack, Greedy, Monotonic Stack | Medium | 51 | 0.5% |
| 106 | Evaluate Division Array, String, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory, Shortest Path | Medium | 51 | 0.6% |
| 107 | Random Pick with Weight Array, Math, Binary Search, Prefix Sum, Randomized | Medium | 51 | 0.5% |
| 108 | Subarray Sums Divisible by K Array, Hash Table, Prefix Sum | Medium | 51 | 0.6% |
| 109 | Capacity To Ship Packages Within D Days Array, Binary Search | Medium | 51 | 0.7% |
| 110 | Minimum Remove to Make Valid Parentheses String, Stack | Medium | 51 | 0.7% |
| 111 | Gas Station Array, Greedy | Medium | 51 | 0.5% |
| 112 | Greatest Common Divisor of Strings Math, String | Easy | 51 | 0.5% |
| 113 | Longest Valid Parentheses String, Dynamic Programming, Stack | Hard | 48 | 0.4% |
| 114 | Multiply Strings Math, String, Simulation | Medium | 48 | 0.4% |
| 115 | Permutations II Array, Backtracking, Sorting | Medium | 48 | 0.6% |
| 116 | Best Time to Buy and Sell Stock II Array, Dynamic Programming, Greedy | Medium | 48 | 0.7% |
| 117 | Find Minimum in Rotated Sorted Array Array, Binary Search | Medium | 48 | 0.5% |
| 118 | Compare Version Numbers Two Pointers, String | Medium | 48 | 0.5% |
| 119 | Rotate Array Array, Math, Two Pointers | Medium | 48 | 0.5% |
| 120 | Move Zeroes Array, Two Pointers | Easy | 48 | 0.6% |
| 121 | Partition Equal Subset Sum Array, Dynamic Programming | Medium | 48 | 0.5% |
| 122 | Design In-Memory File System Hash Table, String, Design, Trie, Sorting | Hard | 48 | 0.5% |
| 123 | Kth Missing Positive Number Array, Binary Search | Easy | 48 | 0.6% |
| 124 | Find the Length of the Longest Common Prefix Array, Hash Table, String, Trie | Medium | 48 | 0.6% |
| 125 | Matchsticks to Square Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask | Medium | 48 | 0.4% |
| 126 | Water and Jug Problem Math, Depth-First Search, Breadth-First Search | Medium | 48 | 0.5% |
| 127 | Brightest Position on Street Array, Sorting, Prefix Sum, Ordered Set | Medium | 48 | 0.6% |
| 128 | Super Egg Drop Math, Binary Search, Dynamic Programming | Hard | 48 | 0.3% |
| 129 | Longest Mountain in Array Array, Two Pointers, Dynamic Programming, Enumeration | Medium | 48 | 0.4% |
| 130 | Next Permutation Array, Two Pointers | Medium | 44 | 0.5% |
| 131 | Minimum Path Sum Array, Dynamic Programming, Matrix | Medium | 44 | 0.7% |
| 132 | Binary Tree Zigzag Level Order Traversal Tree, Breadth-First Search, Binary Tree | Medium | 44 | 0.6% |
| 133 | Intersection of Two Linked Lists Hash Table, Linked List, Two Pointers | Easy | 44 | 0.6% |
| 134 | House Robber II Array, Dynamic Programming | Medium | 44 | 0.5% |
| 135 | Walls and Gates Array, Breadth-First Search, Matrix | Medium | 44 | 0.6% |
| 136 | Remove Invalid Parentheses String, Backtracking, Breadth-First Search | Hard | 44 | 0.5% |
| 137 | Kth Smallest Element in a Sorted Matrix Array, Binary Search, Sorting, Heap (Priority Queue), Matrix | Medium | 44 | 0.6% |
| 138 | Frog Jump Array, Dynamic Programming | Hard | 44 | 0.5% |
| 139 | Split Message Based on Limit String, Enumeration | Hard | 44 | 0.4% |
| 140 | Open the Lock Array, Hash Table, String, Breadth-First Search | Medium | 44 | 0.6% |
| 141 | Convert Binary Search Tree to Sorted Doubly Linked List Linked List, Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree, Doubly-Linked List | Medium | 44 | 0.7% |
| 142 | Reorganize String Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting | Medium | 44 | 0.6% |
| 143 | Score of Parentheses String, Stack | Medium | 44 | 0.6% |
| 144 | Minimize Malware Spread Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Hard | 44 | 0.4% |
| 145 | Remove All Adjacent Duplicates in String II String, Stack | Medium | 44 | 0.6% |
| 146 | Number of Good Leaf Nodes Pairs Tree, Depth-First Search, Binary Tree | Medium | 44 | 0.7% |
| 147 | Minimum Moves to Spread Stones Over Grid Array, Dynamic Programming, Backtracking, Bit Manipulation, Matrix, Bitmask | Medium | 44 | 0.5% |
| 148 | Combinations Backtracking | Medium | 44 | 0.7% |
| 149 | Find All Duplicates in an Array Array, Hash Table, Sorting | Medium | 44 | 0.8% |
| 150 | Min Cost to Connect All Points Array, Union-Find, Graph Theory, Minimum Spanning Tree | Medium | 44 | 0.7% |
| 151 | Reorder Routes to Make All Paths Lead to the City Zero Depth-First Search, Breadth-First Search, Graph Theory | Medium | 44 | 0.7% |
| 152 | Numbers At Most N Given Digit Set Array, Math, String, Binary Search, Dynamic Programming | Hard | 44 | 0.5% |
| 153 | Binary Tree Longest Consecutive Sequence Tree, Depth-First Search, Binary Tree | Medium | 44 | 0.5% |
| 154 | Largest Rectangle in Histogram Array, Stack, Monotonic Stack | Hard | 44 | 0.5% |
| 155 | Shortest Unsorted Continuous Subarray Array, Two Pointers, Stack, Greedy, Sorting, Monotonic Stack | Medium | 44 | 0.4% |
| 156 | Minimum Operations to Write the Letter Y on a Grid Array, Hash Table, Matrix, Counting | Medium | 44 | 0.6% |
| 157 | Course Schedule IV Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Medium | 44 | 0.6% |
| 158 | Integer to Roman Hash Table, Math, String | Medium | 39 | 0.7% |
| 159 | Swap Nodes in Pairs Linked List, Recursion | Medium | 39 | 0.7% |
| 160 | Combination Sum II Array, Backtracking | Medium | 39 | 0.6% |
| 161 | Best Time to Buy and Sell Stock III Array, Dynamic Programming | Hard | 39 | 0.5% |
| 162 | Find All Possible Recipes from Given Supplies Array, Hash Table, String, Graph Theory, Topological Sort | Medium | 39 | 0.6% |
| 163 | Best Time to Buy and Sell Stock IV Array, Dynamic Programming | Hard | 39 | 0.5% |
| 164 | Maximal Square Array, Dynamic Programming, Matrix | Medium | 39 | 0.5% |
| 165 | Longest Substring with At Most K Distinct Characters Hash Table, String, Sliding Window | Medium | 39 | 0.5% |
| 166 | Design Tic-Tac-Toe Array, Hash Table, Design, Matrix, Simulation | Medium | 39 | 0.6% |
| 167 | Search a 2D Matrix Array, Binary Search, Matrix | Medium | 39 | 0.5% |
| 168 | Insert Delete GetRandom O(1) - Duplicates allowed Array, Hash Table, Math, Design, Randomized | Hard | 39 | 0.4% |
| 169 | Remove K Digits String, Stack, Greedy, Monotonic Stack | Medium | 39 | 0.4% |
| 170 | Heaters Array, Two Pointers, Binary Search, Sorting | Medium | 39 | 0.4% |
| 171 | Merge Operations to Turn Array Into a Palindrome Array, Two Pointers, Greedy | Medium | 39 | 0.7% |
| 172 | Design Search Autocomplete System String, Depth-First Search, Design, Trie, Sorting, Heap (Priority Queue), Data Stream | Hard | 39 | 0.5% |
| 173 | Stickers to Spell Word Array, Hash Table, String, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask | Hard | 39 | 0.5% |
| 174 | Best Time to Buy and Sell Stock with Transaction Fee Array, Dynamic Programming, Greedy | Medium | 39 | 0.7% |
| 175 | Max Consecutive Ones III Array, Binary Search, Sliding Window, Prefix Sum | Medium | 39 | 0.7% |
| 176 | Shortest Path in Binary Matrix Array, Breadth-First Search, Matrix | Medium | 39 | 0.5% |
| 177 | Longest Common Subsequence String, Dynamic Programming | Medium | 39 | 0.6% |
| 178 | Number of Visible People in a Queue Array, Stack, Monotonic Stack | Hard | 39 | 0.7% |
| 179 | Maximum Points You Can Obtain from Cards Array, Sliding Window, Prefix Sum | Medium | 39 | 0.6% |
| 180 | Tree Diameter Tree, Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort | Medium | 39 | 0.6% |
| 181 | Maximum Product of Three Numbers Array, Math, Sorting | Easy | 39 | 0.5% |
| 182 | Snakes and Ladders Array, Breadth-First Search, Matrix | Medium | 39 | 0.5% |
| 183 | 2 Keys Keyboard Math, Dynamic Programming | Medium | 39 | 0.6% |
| 184 | Sentence Similarity III Array, Two Pointers, String | Medium | 39 | 0.5% |
| 185 | Unique Paths II Array, Dynamic Programming, Matrix | Medium | 39 | 0.4% |
| 186 | Make Costs of Paths Equal in a Binary Tree Array, Dynamic Programming, Greedy, Tree, Binary Tree | Medium | 39 | 0.6% |
| 187 | Minimum Cost For Tickets Array, Dynamic Programming | Medium | 39 | 0.7% |
| 188 | Regions Cut By Slashes Array, Hash Table, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Medium | 39 | 0.8% |
| 189 | Design Memory Allocator Array, Hash Table, Design, Simulation | Medium | 39 | 0.5% |
| 190 | Robot Room Cleaner Backtracking, Interactive | Hard | 39 | 0.8% |
| 191 | Cheapest Flights Within K Stops Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path | Medium | 39 | 0.4% |
| 192 | Path Sum III Tree, Depth-First Search, Binary Tree | Medium | 39 | 0.5% |
| 193 | Merge Two Sorted Lists Linked List, Recursion | Easy | 33 | 0.7% |
| 194 | Insert Interval Array | Medium | 33 | 0.5% |
| 195 | Remove Duplicates from Sorted Array II Array, Two Pointers | Medium | 33 | 0.6% |
| 196 | Reverse Linked List II Linked List | Medium | 33 | 0.5% |
| 197 | Path Sum II Backtracking, Tree, Depth-First Search, Binary Tree | Medium | 33 | 0.6% |
| 198 | Valid Palindrome Two Pointers, String | Easy | 33 | 0.5% |
| 199 | Sort List Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort | Medium | 33 | 0.6% |
| 200 | Reverse Words in a String Two Pointers, String | Medium | 33 | 0.6% |
| 201 | Maximum Product Subarray Array, Dynamic Programming | Medium | 33 | 0.4% |
| 202 | Longest Substring with At Most Two Distinct Characters Hash Table, String, Sliding Window | Medium | 33 | 0.6% |
| 203 | Step-By-Step Directions From a Binary Tree Node to Another String, Tree, Depth-First Search, Binary Tree | Medium | 33 | 0.6% |
| 204 | Largest Number Array, String, Greedy, Sorting | Medium | 33 | 0.4% |
| 205 | Number of Islands II Array, Hash Table, Union-Find | Hard | 33 | 0.4% |
| 206 | Shortest Distance from All Buildings Array, Breadth-First Search, Matrix | Hard | 33 | 0.4% |
| 207 | Non-overlapping Intervals Array, Dynamic Programming, Greedy, Sorting | Medium | 33 | 0.6% |
| 208 | String Compression Two Pointers, String | Medium | 33 | 0.6% |
| 209 | LFU Cache Hash Table, Linked List, Design, Doubly-Linked List | Hard | 33 | 0.5% |
| 210 | Coin Change II Array, Dynamic Programming | Medium | 33 | 0.6% |
| 211 | Contiguous Array Array, Hash Table, Prefix Sum | Medium | 33 | 0.5% |
| 212 | Count Pairs Of Similar Strings Array, Hash Table, String, Bit Manipulation, Counting | Easy | 33 | 0.7% |
| 213 | Task Scheduler Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting | Medium | 33 | 0.6% |
| 214 | Find K Closest Elements Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue) | Medium | 33 | 0.5% |
| 215 | Maximum Width of Binary Tree Tree, Depth-First Search, Breadth-First Search, Binary Tree | Medium | 33 | 0.5% |
| 216 | Valid Palindrome II Two Pointers, String, Greedy | Easy | 33 | 0.4% |
| 217 | Number of Atoms Hash Table, String, Stack, Sorting | Hard | 33 | 0.7% |
| 218 | Is Graph Bipartite? Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Medium | 33 | 0.6% |
| 219 | Champagne Tower Dynamic Programming | Medium | 33 | 0.6% |
| 220 | Sum of Subarray Minimums Array, Dynamic Programming, Stack, Monotonic Stack | Medium | 33 | 0.4% |
| 221 | Minimum Increment to Make Array Unique Array, Greedy, Sorting, Counting | Medium | 33 | 0.6% |
| 222 | Pairs of Songs With Total Durations Divisible by 60 Array, Hash Table, Counting | Medium | 33 | 0.5% |
| 223 | Search Suggestions System Array, String, Binary Search, Trie, Sorting, Heap (Priority Queue) | Medium | 33 | 0.7% |
| 224 | Minimum Difficulty of a Job Schedule Array, Dynamic Programming | Hard | 33 | 0.6% |
| 225 | Furthest Building You Can Reach Array, Greedy, Heap (Priority Queue) | Medium | 33 | 0.5% |
| 226 | Remove Nth Node From End of List Linked List, Two Pointers | Medium | 33 | 0.5% |
| 227 | Concatenated Words Array, String, Dynamic Programming, Depth-First Search, Trie, Sorting | Hard | 33 | 0.5% |
| 228 | My Calendar I Array, Binary Search, Design, Segment Tree, Ordered Set | Medium | 33 | 0.6% |
| 229 | Number of Connected Components in an Undirected Graph Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Medium | 33 | 0.7% |
| 230 | Permutation in String Hash Table, Two Pointers, String, Sliding Window | Medium | 33 | 0.5% |
| 231 | Replace Words Array, Hash Table, String, Trie | Medium | 33 | 0.7% |
| 232 | Candy Array, Greedy | Hard | 33 | 0.5% |
| 233 | Delete and Earn Array, Hash Table, Dynamic Programming | Medium | 33 | 0.6% |
| 234 | Max Stack Linked List, Stack, Design, Doubly-Linked List, Ordered Set | Hard | 33 | 0.5% |
| 235 | House Robber III Dynamic Programming, Tree, Depth-First Search, Binary Tree | Medium | 33 | 0.6% |
| 236 | Time Based Key-Value Store Hash Table, String, Binary Search, Design | Medium | 33 | 0.5% |
| 237 | Diameter of Binary Tree Tree, Depth-First Search, Binary Tree | Easy | 33 | 0.7% |
| 238 | Maximum Width Ramp Array, Two Pointers, Stack, Monotonic Stack | Medium | 33 | 0.6% |
| 239 | Find the Duplicate Number Array, Two Pointers, Binary Search, Bit Manipulation | Medium | 33 | 0.6% |
| 240 | All Nodes Distance K in Binary Tree Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree | Medium | 33 | 0.7% |
| 241 | Best Time to Buy and Sell Stock with Cooldown Array, Dynamic Programming | Medium | 33 | 0.6% |
| 242 | Letter Case Permutation String, Backtracking, Bit Manipulation | Medium | 33 | 0.8% |
| 243 | Minimum Number of Arrows to Burst Balloons Array, Greedy, Sorting | Medium | 33 | 0.6% |
| 244 | Add Bold Tag in String Array, Hash Table, String, Trie, String Matching | Medium | 33 | 0.5% |
| 245 | Longest Duplicate Substring String, Binary Search, Sliding Window, Rolling Hash, Suffix Array, Hash Function | Hard | 33 | 0.3% |
| 246 | Roman to Integer Hash Table, Math, String | Easy | 33 | 0.7% |
| 247 | Deepest Leaves Sum Tree, Depth-First Search, Breadth-First Search, Binary Tree | Medium | 33 | 0.9% |
| 248 | Count Number of Nice Subarrays Array, Hash Table, Math, Sliding Window, Prefix Sum | Medium | 33 | 0.8% |
| 249 | Flatten Deeply Nested Array | Medium | 33 | 0.7% |
| 250 | Merge In Between Linked Lists Linked List | Medium | 33 | 0.8% |
| 251 | Accounts Merge Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union-Find, Sorting | Medium | 33 | 0.6% |
| 252 | Find All Anagrams in a String Hash Table, String, Sliding Window | Medium | 33 | 0.5% |
| 253 | Product of the Last K Numbers Array, Math, Design, Data Stream, Prefix Sum | Medium | 33 | 0.6% |
| 254 | Fruit Into Baskets Array, Hash Table, Sliding Window | Medium | 33 | 0.5% |
| 255 | Rotate Image Array, Math, Matrix | Medium | 33 | 0.8% |
| 256 | Serialize and Deserialize N-ary Tree String, Tree, Depth-First Search, Breadth-First Search | Hard | 33 | 0.7% |
| 257 | Add Two Numbers Linked List, Math, Recursion | Medium | 24 | 0.5% |
| 258 | Median of Two Sorted Arrays Array, Binary Search, Divide and Conquer | Hard | 24 | 0.5% |
| 259 | Valid Sudoku Array, Hash Table, Matrix | Medium | 24 | 0.6% |
| 260 | Pow(x, n) Math, Recursion | Medium | 24 | 0.4% |
| 261 | Spiral Matrix II Array, Matrix, Simulation | Medium | 24 | 0.8% |
| 262 | Unique Paths Math, Dynamic Programming, Combinatorics | Medium | 24 | 0.7% |
| 263 | Plus One Array, Math | Easy | 24 | 0.5% |
| 264 | Decode Ways String, Dynamic Programming | Medium | 24 | 0.4% |
| 265 | Unique Binary Search Trees Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree | Medium | 24 | 0.6% |
| 266 | Path Sum Tree, Depth-First Search, Breadth-First Search, Binary Tree | Easy | 24 | 0.6% |
| 267 | Parallel Courses III Array, Dynamic Programming, Graph Theory, Topological Sort | Hard | 24 | 0.7% |
| 268 | Happy Number Hash Table, Math, Two Pointers | Easy | 24 | 0.6% |
| 269 | Implement Trie (Prefix Tree) Hash Table, String, Design, Trie | Medium | 24 | 0.7% |
| 270 | Search a 2D Matrix II Array, Binary Search, Divide and Conquer, Matrix | Medium | 24 | 0.6% |
| 271 | 3Sum Smaller Array, Two Pointers, Binary Search, Sorting | Medium | 24 | 0.5% |
| 272 | Graph Valid Tree Depth-First Search, Breadth-First Search, Union-Find, Graph Theory | Medium | 24 | 0.5% |
| 273 | Expression Add Operators Math, String, Backtracking | Hard | 24 | 0.4% |
| 274 | Rearrange String k Distance Apart Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting | Hard | 24 | 0.4% |
| 275 | Add Two Numbers II Linked List, Math, Stack | Medium | 24 | 0.6% |
| 276 | 132 Pattern Array, Binary Search, Stack, Monotonic Stack, Ordered Set | Medium | 24 | 0.3% |
| 277 | Validate IP Address String | Medium | 24 | 0.3% |
| 278 | Diagonal Traverse Array, Matrix, Simulation | Medium | 24 | 0.7% |
| 279 | Number of Longest Increasing Subsequence Array, Dynamic Programming, Binary Indexed Tree, Segment Tree | Medium | 24 | 0.5% |
| 280 | Subarrays with K Different Integers Array, Hash Table, Sliding Window, Counting | Hard | 24 | 0.7% |
| 281 | Cousins in Binary Tree Tree, Depth-First Search, Breadth-First Search, Binary Tree | Easy | 24 | 0.6% |
| 282 | Dot Product of Two Sparse Vectors Array, Hash Table, Two Pointers, Design | Medium | 24 | 0.9% |
| 283 | Minimum Swaps to Group All 1's Together II Array, Sliding Window | Medium | 24 | 0.7% |
| 284 | Valid Word Abbreviation Two Pointers, String | Easy | 24 | 0.4% |
| 285 | Combination Sum IV Array, Dynamic Programming | Medium | 24 | 0.6% |
| 286 | Process Tasks Using Servers Array, Heap (Priority Queue) | Medium | 24 | 0.4% |
| 287 | Maximal Score After Applying K Operations Array, Greedy, Heap (Priority Queue) | Medium | 24 | 0.6% |
| 288 | Find the Celebrity Two Pointers, Graph Theory, Interactive | Medium | 24 | 0.5% |
| 289 | Insert into a Sorted Circular Linked List Linked List | Medium | 24 | 0.4% |
| 290 | Minimum Number of Operations to Move All Balls to Each Box Array, String, Prefix Sum | Medium | 24 | 0.9% |
| 291 | Copy List with Random Pointer Hash Table, Linked List | Medium | 24 | 0.6% |
| 292 | The Maze II Array, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Matrix, Shortest Path | Medium | 24 | 0.6% |
| 293 | Top K Frequent Words Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting | Medium | 24 | 0.6% |
| 294 | Valid Palindrome III String, Dynamic Programming | Hard | 24 | 0.5% |
| 295 | Arithmetic Slices Array, Dynamic Programming, Sliding Window | Medium | 24 | 0.6% |
| 296 | Find Positive Integer Solution for a Given Equation Math, Two Pointers, Binary Search, Interactive | Medium | 24 | 0.7% |
| 297 | Maximum Spending After Buying Items Array, Greedy, Sorting, Heap (Priority Queue), Matrix | Hard | 24 | 0.6% |
| 298 | K-th Smallest in Lexicographical Order Trie | Hard | 24 | 0.5% |
| 299 | Rearranging Fruits Array, Hash Table, Greedy, Sort | Hard | 24 | 0.6% |
| 300 | Parallel Courses Graph Theory, Topological Sort | Medium | 24 | 0.6% |
| 301 | Convert Sorted Array to Binary Search Tree Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree | Easy | 24 | 0.8% |
| 302 | Maximum Performance of a Team Array, Greedy, Sorting, Heap (Priority Queue) | Hard | 24 | 0.5% |
| 303 | Two Sum II - Input Array Is Sorted Array, Two Pointers, Binary Search | Medium | 24 | 0.7% |
| 304 | Maximum Profit in Job Scheduling Array, Binary Search, Dynamic Programming, Sorting | Hard | 24 | 0.5% |
| 305 | Kth Smallest Element in a BST Tree, Depth-First Search, Binary Search Tree, Binary Tree | Medium | 24 | 0.8% |
| 306 | Construct String from Binary Tree String, Tree, Depth-First Search, Binary Tree | Medium | 24 | 0.7% |
| 307 | Add Two Integers Math | Easy | 24 | 0.9% |
| 308 | Put Marbles in Bags Array, Greedy, Sorting, Heap (Priority Queue) | Hard | 24 | 0.7% |
| 309 | Remove Duplicates from Sorted List II Linked List, Two Pointers | Medium | 24 | 0.5% |
| 310 | Valid Mountain Array Array | Easy | 24 | 0.4% |
| 311 | Human Traffic of Stadium Database | Hard | 24 | 0.5% |
| 312 | Sparse Matrix Multiplication Array, Hash Table, Matrix | Medium | 24 | 0.7% |
| 313 | Event Emitter | Medium | 24 | 0.8% |
| 314 | Minesweeper Array, Depth-First Search, Breadth-First Search, Matrix | Medium | 24 | 0.7% |
| 315 | Valid Square Math, Geometry | Medium | 24 | 0.5% |
| 316 | Symmetric Tree Tree, Depth-First Search, Breadth-First Search, Binary Tree | Easy | 24 | 0.6% |
| 317 | Find Maximum Non-decreasing Array Length Array, Binary Search, Dynamic Programming, Stack, Queue, Monotonic Stack, Prefix Sum, Monotonic Queue | Hard | 24 | 0.2% |
| 318 | Range Frequency Queries Array, Hash Table, Binary Search, Design, Segment Tree | Medium | 24 | 0.4% |
| 319 | Candy Crush Array, Two Pointers, Matrix, Simulation | Medium | 24 | 0.8% |
| 320 | Shortest Subarray to be Removed to Make Array Sorted Array, Two Pointers, Binary Search, Stack, Monotonic Stack | Medium | 24 | 0.5% |
| 321 | Count the Number of Good Subarrays Array, Hash Table, Sliding Window | Medium | 24 | 0.7% |
| 322 | Consecutive Numbers Sum Math, Enumeration | Hard | 24 | 0.4% |
| 323 | Recover Binary Search Tree Tree, Depth-First Search, Binary Search Tree, Binary Tree | Medium | 24 | 0.6% |
| 324 | Wiggle Sort Array, Greedy, Sorting | Medium | 24 | 0.7% |
| 325 | Implement Queue using Stacks Stack, Design, Queue | Easy | 24 | 0.7% |
| 326 | Next Greater Element I Array, Hash Table, Stack, Monotonic Stack | Easy | 24 | 0.8% |
| 327 | Encode and Decode Strings Array, String, Design | Medium | 24 | 0.5% |
| 328 | Verify Preorder Sequence in Binary Search Tree Array, Stack, Tree, Binary Search Tree, Recursion, Monotonic Stack, Binary Tree | Medium | 24 | 0.5% |
| 329 | Number of Adjacent Elements With the Same Color Array | Medium | 24 | 0.6% |
| 330 | 24 Game Array, Math, Backtracking | Hard | 24 | 0.6% |
| 331 | Count Binary Substrings Two Pointers, String | Easy | 24 | 0.7% |
| 332 | Maximum Size Subarray Sum Equals k Array, Hash Table, Prefix Sum | Medium | 24 | 0.5% |
| 333 | Employee Free Time Array, Sweep Line, Sorting, Heap (Priority Queue) | Hard | 24 | 0.7% |
| 334 | Minimum Operations to Make the Array Increasing Array, Greedy | Easy | 24 | 0.8% |
| 335 | Nth Digit Math, Binary Search | Medium | 24 | 0.4% |
| 336 | Valid Tic-Tac-Toe State Array, Matrix | Medium | 24 | 0.3% |
| 337 | Robot Bounded In Circle Math, String, Simulation | Medium | 24 | 0.6% |
| 338 | Word Pattern II Hash Table, String, Backtracking | Medium | 24 | 0.5% |
| 339 | Partition to K Equal Sum Subsets Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask | Medium | 24 | 0.4% |
| 340 | Minimum Absolute Difference Between Elements With Constraint Array, Binary Search, Ordered Set | Medium | 24 | 0.4% |
| 341 | Department Top Three Salaries Database | Hard | 24 | 0.6% |
| 342 | Construct Binary Tree from Inorder and Postorder Traversal Array, Hash Table, Divide and Conquer, Tree, Binary Tree | Medium | 24 | 0.7% |
| 343 | Implement Rand10() Using Rand7() Math, Rejection Sampling, Randomized, Probability and Statistics | Medium | 24 | 0.5% |
| 344 | Flip Game II Math, Dynamic Programming, Backtracking, Memoization, Game Theory | Medium | 24 | 0.5% |
| 345 | Lowest Common Ancestor of a Binary Tree IV Hash Table, Tree, Depth-First Search, Binary Tree | Medium | 24 | 0.8% |
| 346 | Surrounded Regions Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix | Medium | 24 | 0.5% |
| 347 | Next Greater Element II Array, Stack, Monotonic Stack | Medium | 24 | 0.7% |
| 348 | All O`one Data Structure Hash Table, Linked List, Design, Doubly-Linked List | Hard | 24 | 0.4% |
| 349 | Unit Conversion II Array, Math, Depth-First Search, Breadth-First Search, Graph Theory | Medium | 24 | 0.7% |
| 350 | Maximum Number of Events That Can Be Attended Array, Greedy, Sorting, Heap (Priority Queue) | Medium | 24 | 0.4% |
| 351 | Maximum Sum Circular Subarray Array, Divide and Conquer, Dynamic Programming, Queue, Monotonic Queue | Medium | 24 | 0.5% |
How to read this list
The tabs at the top split the questions by how recently people said they were asked in interviews. "Last 30 Days" is the past month, "Last 3 Months" is the past quarter, and so on. "All Time" is every question on record for this company.
Frequency is a score from 0 to 100 for how often a question showed up in that time window. A higher number means it came up more often, so the list starts with the most common questions first. Acceptance is the share of submissions that pass on LeetCode. Click any question to open it on LeetCode.