| 1 |
Two Sum |
Easy |
|
| 2 |
Add Two Numbers |
Medium |
|
| 3 |
Longest Substring Without Repeating Characters |
Medium |
|
| 4 |
Median of Two Sorted Arrays |
Hard |
|
| 5 |
Longest Palindromic Substring |
Medium |
|
| 7 |
Reverse Integer |
Easy |
|
| 8 |
String to Integer (atoi) |
Medium |
|
| 10 |
Regular Expression Matching |
Hard |
|
| 11 |
Container With Most Water |
Medium |
|
| 13 |
Roman to Integer |
Easy |
|
| 14 |
Longest Common Prefix |
Easy |
|
| 15 |
3Sum |
Medium |
|
| 17 |
Letter Combinations of a Phone Number |
Medium |
|
| 19 |
Remove Nth Node From End of List |
Medium |
|
| 20 |
Valid Parentheses |
Easy |
|
| 21 |
Merge Two Sorted Lists |
Easy |
|
| 22 |
Generate Parentheses |
Medium |
|
| 23 |
Merge k Sorted Lists |
Hard |
|
| 26 |
Remove Duplicates from Sorted Array |
Easy |
|
| 28 |
Implement strStr() |
Easy |
|
| 29 |
Divide Two Integers |
Medium |
|
| 33 |
Search in Rotated Sorted Array |
Medium |
|
| 34 |
Find First and Last Position of Element in Sorted Array |
Medium |
|
| 36 |
Valid Sudoku |
Medium |
|
| 38 |
Count and Say |
Medium |
|
| 41 |
First Missing Positive |
Hard |
|
| 42 |
Trapping Rain Water |
Hard |
|
| 44 |
Wildcard Matching |
Hard |
|
| 46 |
Permutations |
Medium |
|
| 48 |
Rotate Image |
Medium |
|
| 49 |
Group Anagrams |
Medium |
|
| 50 |
Pow(x, n) |
Medium |
|
| 53 |
Maximum Subarray |
Easy |
|
| 54 |
Spiral Matrix |
Medium |
|
| 55 |
Jump Game |
Medium |
|
| 56 |
Merge Intervals |
Medium |
|
| 62 |
Unique Paths |
Medium |
|
| 66 |
Plus One |
Easy |
|
| 69 |
Sqrt(x) |
Easy |
|
| 70 |
Climbing Stairs |
Easy |
|
| 73 |
Set Matrix Zeroes |
Medium |
|
| 75 |
Sort Colors |
Medium |
|
| 76 |
Minimum Window Substring |
Hard |
|
| 78 |
Subsets |
Medium |
|
| 79 |
Word Search |
Medium |
|
| 84 |
Largest Rectangle in Histogram |
Hard |
|
| 88 |
Merge Sorted Array |
Easy |
|
| 91 |
Decode Ways |
Medium |
|
| 94 |
Binary Tree Inorder Traversal |
Medium |
|
| 98 |
Validate Binary Search Tree |
Medium |
|
| 101 |
Symmetric Tree |
Easy |
|
| 102 |
Binary Tree Level Order Traversal |
Medium |
|
| 103 |
Binary Tree Zigzag Level Order Traversal |
Medium |
|
| 104 |
Maximum Depth of Binary Tree |
Easy |
|
| 105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Medium |
|
| 108 |
Convert Sorted Array to Binary Search Tree |
Easy |
|
| 116 |
Populating Next Right Pointers in Each Node |
Medium |
|
| 118 |
Pascal’s Triangle |
Easy |
|
| 121 |
Best Time to Buy and Sell Stock |
Easy |
|
| 122 |
Best Time to Buy and Sell Stock II |
Easy |
|
| 124 |
Binary Tree Maximum Path Sum |
Hard |
|
| 125 |
Valid Palindrome |
Easy |
|
| 127 |
Word Ladder |
Hard |
|
| 128 |
Longest Consecutive Sequence |
Hard |
|
| 130 |
Surrounded Regions |
Medium |
|
| 131 |
Palindrome Partitioning |
Medium |
|
| 134 |
Gas Station |
Medium |
|
| 136 |
Single Number |
Easy |
|
| 138 |
Copy List with Random Pointer |
Medium |
|
| 139 |
Word Break |
Medium |
|
| 140 |
Word Break II |
Hard |
|
| 141 |
Linked List Cycle |
Easy |
|
| 146 |
LRU Cache |
Medium |
|
| 148 |
Sort List |
Medium |
|
| 149 |
Max Points on a Line |
Hard |
|
| 150 |
Evaluate Reverse Polish Notation |
Medium |
|
| 152 |
Maximum Product Subarray |
Medium |
|
| 155 |
Min Stack |
Easy |
|
| 160 |
Intersection of Two Linked Lists |
Easy |
|
| 162 |
Find Peak Element |
Medium |
|
| 163 |
Missing Ranges |
Easy |
|
| 166 |
Fraction to Recurring Decimal |
Medium |
|
| 169 |
Majority Element |
Easy |
|
| 171 |
Excel Sheet Column Number |
Easy |
|
| 172 |
Factorial Trailing Zeroes |
Easy |
|
| 179 |
Largest Number |
Medium |
|
| 189 |
Rotate Array |
Medium |
|
| 190 |
Reverse Bits |
Easy |
|
| 191 |
Number of 1 Bits |
Easy |
|
| 198 |
House Robber |
Medium |
|
| 200 |
Number of Islands |
Medium |
|
| 202 |
Happy Number |
Easy |
|
| 204 |
Count Primes |
Easy |
|
| 206 |
Reverse Linked List |
Easy |
|
| 207 |
Course Schedule |
Medium |
|
| 208 |
Implement Trie (Prefix Tree) |
Medium |
|
| 210 |
Course Schedule II |
Medium |
|
| 212 |
Word Search II |
Hard |
|
| 215 |
Kth Largest Element in an Array |
Medium |
|
| 217 |
Contains Duplicate |
Easy |
|
| 218 |
The Skyline Problem |
Hard |
|
| 227 |
Basic Calculator II |
Medium |
|
| 230 |
Kth Smallest Element in a BST |
Medium |
|
| 234 |
Palindrome Linked List |
Easy |
|
| 236 |
Lowest Common Ancestor of a Binary Tree |
Medium |
|
| 237 |
Delete Node in a Linked List |
Easy |
|
| 238 |
Product of Array Except Self |
Medium |
|
| 239 |
Sliding Window Maximum |
Hard |
|
| 240 |
Search a 2D Matrix II |
Medium |
|
| 242 |
Valid Anagram |
Easy |
|
| 251 |
Flatten 2D Vector |
Medium |
|
| 253 |
Meeting Rooms II |
Medium |
|
| 268 |
Missing Number |
Easy |
|
| 269 |
Alien Dictionary |
Hard |
|
| 277 |
Find the Celebrity |
Medium |
|
| 279 |
Perfect Squares |
Medium |
|
| 283 |
Move Zeroes |
Easy |
|
| 285 |
Inorder Successor in BST |
Medium |
|
| 287 |
Find the Duplicate Number |
Medium |
|
| 289 |
Game of Life |
Medium |
|
| 295 |
Find Median from Data Stream |
Hard |
|
| 297 |
Serialize and Deserialize Binary Tree |
Hard |
|
| 300 |
Longest Increasing Subsequence |
Medium |
|
| 308 |
Range Sum Query 2D - Mutable |
Hard |
|
| 315 |
Count of Smaller Numbers After Self |
Hard |
|
| 322 |
Coin Change |
Medium |
|
| 324 |
Wiggle Sort II |
Medium |
|
| 326 |
Power of Three |
Easy |
|
| 328 |
Odd Even Linked List |
Medium |
|
| 329 |
Longest Increasing Path in a Matrix |
Hard |
|
| 334 |
Increasing Triplet Subsequence |
Medium |
|
| 340 |
Longest Substring with At Most K Distinct Characters |
Medium |
|
| 341 |
Flatten Nested List Iterator |
Medium |
|
| 344 |
Reverse String |
Easy |
|
| 347 |
Top K Frequent Elements |
Medium |
|
| 348 |
Design Tic-Tac-Toe |
Medium |
|
| 350 |
Intersection of Two Arrays II |
Easy |
|
| 371 |
Sum of Two Integers |
Medium |
|
| 378 |
Kth Smallest Element in a Sorted Matrix |
Medium |
|
| 380 |
Insert Delete GetRandom O(1) |
Medium |
|
| 384 |
Shuffle an Array |
Medium |
|
| 387 |
First Unique Character in a String |
Easy |
|
| 395 |
Longest Substring with At Least K Repeating Characters |
Medium |
|
| 412 |
Fizz Buzz |
Easy |
|
| 454 |
4Sum II |
Medium |
|