| 1 |
Easy |
Two Sum |
Java, Python, Ruby |
| 2 |
Medium |
Add Two Numbers |
C |
| 3 |
Medium |
Longest Substring Without Repeating Characters |
Python |
| 4 |
Hard |
Median of Two Sorted Arrays |
Python |
| 5 |
Medium |
Longest Palindromic Substring |
Python |
| 6 |
Medium |
Zig Zag Conversion |
Java |
| 7 |
Easy |
Reverse Integer |
Python |
| 8 |
Medium |
String to Integer |
Ruby |
| 9 |
Easy |
Palindrome Number |
C, Java, Python, Swift |
| 10 |
Hard |
Regular Expression Matching |
Python |
| 11 |
Medium |
Container With Most Water |
Python |
| 12 |
Medium |
Integer to Roman |
Python |
| 13 |
Easy |
Roman to Integer |
C, Python |
| 14 |
Easy |
Longest Common Prefix |
Python |
| 15 |
Medium |
3Sum |
Python |
| 16 |
Medium |
3Sum Closest |
Python |
| 17 |
Medium |
Letter Combinations of a Phone Number |
Python |
| 18 |
Medium |
4Sum |
Python |
| 19 |
Medium |
Remove Nth Node From End of List |
Python |
| 20 |
Easy |
Valid Parentheses |
Java, Python |
| 21 |
Easy |
Merge Two Sorted Lists |
Java, Python |
| 22 |
Medium |
Generate Parentheses |
Python |
| 23 |
Hard |
Merge k Sorted Lists |
Python |
| 24 |
Medium |
Swap Node in Pairs |
Python |
| 25 |
Hard |
Reverse Nodes in k-Group |
Python |
| 26 |
Easy |
Remove Duplicates from Sorted Array |
C, Python |
| 27 |
Easy |
Remove Element |
Python |
| 28 |
Easy |
Implement strStr() |
C, Python |
| 29 |
Medium |
Divide Two Integers |
Python |
| 31 |
Medium |
Next Permutation |
Python |
| 33 |
Medium |
Search in Rotated Sorted Array |
Python |
| 34 |
Medium |
Find First and Last Position of Element in Sorted Array |
Python |
| 35 |
Easy |
Search Insert Position |
Go, Java, JavaScript, Scala |
| 36 |
Medium |
Valid Sudoku |
Python |
| 38 |
Easy |
Count and Say |
Python |
| 39 |
Medium |
Combination Sum |
Python |
| 40 |
Medium |
Combination Sum II |
Python |
| 42 |
Hard |
Trapping Rain Water |
Python |
| 43 |
Medium |
Multiply Strings |
Python |
| 44 |
Hard |
Wildcard Matching |
Python |
| 46 |
Medium |
Permutations |
Python |
| 47 |
Medium |
Permutations II |
Python |
| 48 |
Medium |
Rotate Image |
Python |
| 49 |
Medium |
Group Anagrams |
Python |
| 50 |
Medium |
Pow(x, n) |
Python |
| 53 |
Easy |
Maximum Subarray |
Java |
| 54 |
Medium |
Spiral Matrix |
Python |
| 55 |
Medium |
Jump Game |
Python |
| 56 |
Medium |
Merge Intervals |
Python |
| 58 |
Easy |
Length of Last Word |
Python |
| 62 |
Medium |
Unique Paths |
Python |
| 63 |
Medium |
Unique Paths II |
Python |
| 64 |
Medium |
Minimum Path Sum |
Python |
| 66 |
Easy |
Plus One |
Python |
| 67 |
Easy |
Add Binary |
Python |
| 69 |
Easy |
Sqrt() |
Python |
| 70 |
Easy |
Climbing Stairs |
C |
| 76 |
Hard |
Minimum Window Substring |
Python |
| 78 |
Medium |
Subsets |
Python |
| 79 |
Medium |
Word Search |
Python |
| 83 |
Easy |
Remove Duplicates from Sorted List |
Python |
| 84 |
Hard |
Largest Rectangle in Histogram |
Python |
| 85 |
Hard |
Maximal Rectangle |
Python |
| 88 |
Easy |
Merge Sorted Array |
Python |
| 100 |
Easy |
Same Tree |
Python |
| 101 |
Easy |
Symmetric Tree |
Python |
| 102 |
Medium |
Binary Tree Level Order Traversal |
Python |
| 104 |
Easy |
Maximum Depth of Binary Tree |
Python |
| 105 |
Medium |
Construct Binary Tree from Preorder and Inorder Traversal |
Python |
| 106 |
Medium |
Construct Binary Tree from Inorder and Postorder Traversal |
Python |
| 107 |
Easy |
Binary Tree Level Order Traversal II |
Python |
| 108 |
Easy |
Convert Sorted Array to Binary Search Tree |
Python |
| 110 |
Easy |
Balanced Binary Tree |
Python |
| 111 |
Easy |
Minimum Depth of Binary Tree |
Python |
| 112 |
Easy |
Path Sum |
Python |
| 118 |
Easy |
Pascal's Triangle |
Python |
| 121 |
Easy |
Best Time to Buy and Sell Stock |
Python |
| 122 |
Easy |
Best Time to Buy and Sell Stock II |
Python |
| 123 |
Hard |
Best Time to Buy and Sell Stock III |
Python |
| 125 |
Easy |
Valid Palindrome |
Python |
| 127 |
Medium |
Word Ladder |
Python |
| 133 |
Medium |
Clone Graph |
Python |
| 136 |
Easy |
Single Number |
Python |
| 137 |
Medium |
Single Number II |
Python |
| 139 |
Medium |
Word Break |
Python |
| 141 |
Easy |
Linked List Cycle |
Python |
| 142 |
Medium |
Linked List Cycle II |
Python |
| 146 |
Hard |
LRU Cache |
Python |
| 148 |
Medium |
Sort List |
Python |
| 153 |
Medium |
Find Minimum in Rotated Sorted Array |
Python |
| 155 |
Easy |
Min Stack |
Python |
| 162 |
Medium |
Find Peak Element |
Python |
| 168 |
Easy |
Excel Sheet Column Title |
Python |
| 171 |
Easy |
Excel Sheet Column Number |
Python |
| 173 |
Medium |
Binary Search Tree Iterator |
Python |
| 188 |
Hard |
Best Time to Buy and Sell Stock IV |
Python |
| 191 |
Easy |
Number of 1 Bits |
Python |
| 196 |
Easy |
Delete Duplicate Emails |
SQL |
| 200 |
Medium |
Number of Islands |
Python |
| 204 |
Easy |
Count Primes |
Python |
| 206 |
Easy |
Reverse Linked List |
Python |
| 207 |
Medium |
Course Schedule |
Python |
| 208 |
Medium |
Implement Trie |
Java, Python |
| 215 |
Medium |
Kth Largest Element in an Array |
Python |
| 218 |
Hard |
The Skyline Problem |
Python |
| 226 |
Easy |
Invert Binary Tree |
Python |
| 231 |
Easy |
Power Of Two |
Python |
| 234 |
Easy |
Palindrome Linked List |
Python |
| 235 |
Easy |
Lowest Common Ancestor of a Binary Search Tree |
Python |
| 236 |
Medium |
Lowest Common Ancestor of a Binary Tree |
Python |
| 237 |
Easy |
Delete Node in a Linked List |
Python |
| 238 |
Medium |
Product of Array Except Self |
Python |
| 240 |
Medium |
Search a 2D Matrix II |
Python |
| 258 |
Easy |
Add Digits |
Python |
| 268 |
Easy |
Missing Number |
Python |
| 273 |
Hard |
Integer to English Words |
Python |
| 283 |
Easy |
Move Zeroes |
Python |
| 287 |
Medium |
Find the Duplicate Number |
Python |
| 295 |
Hard |
Find Median from Data Stream |
Python |
| 297 |
Hard |
Serialize and Deserialize Binary Tree |
Java |
| 301 |
Hard |
Remove Invalid Parentheses |
Python |
| 310 |
Medium |
Minimum Height Trees |
Python |
| 341 |
Medium |
Flatten Nested List Iterator |
Python |
| 344 |
Easy |
Reverse String |
Python |
| 388 |
Medium |
Longest Absolute File Path |
Python |
| 389 |
Easy |
Find the Difference |
Python |
| 461 |
Easy |
Hamming Distance |
Python |
| 495 |
Medium |
Teemo Attacking |
Python |
| 535 |
Medium |
Encode and Decode TinyURL |
Python |
| 733 |
Easy |
Flood Fill |
Python |
| 771 |
Easy |
Jewels and Stones |
Python |
| 1114 |
Easy |
Print in Order |
Python |