| 1 |
Two Sum |
Python C++ |
Easy |
| 2 |
Add Two Numbers |
Python |
Medium |
| 3 |
Longest Substring Without Repeating Characters |
Python |
Medium |
| 4 |
Median of Two Sorted Arrays |
Python |
Hard |
| 9 |
Palindrome Number |
Python C++ |
Easy |
| 13 |
Roman to Integer |
Python |
Easy |
| 14 |
Longest Common Prefix |
Python |
Easy |
| 19 |
Remove Nth Node From End of List |
Python |
Medium |
| 20 |
Valid Parentheses |
Python |
Easy |
| 21 |
Merge Two Sorted Lists |
Python |
Easy |
| 22 |
Generate Parentheses |
Python |
Medium |
| 24 |
Swap Nodes in Pairs |
Python |
Medium |
| 26 |
Remove Duplicates from Sorted Array |
Python |
Easy |
| 27 |
Remove Element |
Python |
Easy |
| 28 |
Find the Index of the First Occurrence in a String |
Python |
Easy |
| 33 |
Search in Rotated Sorted Array |
Python |
Medium |
| 34 |
Find First and Last Position of Element in Sorted Array |
Python |
Medium |
| 35 |
Search Insert Position |
Python |
Easy |
| 36 |
Valid Sudoku |
Python |
Medium |
| 46 |
Permutations |
Python |
Medium |
| 49 |
Group Anagrams |
Python |
Medium |
| 50 |
Pow(x, n) |
Python |
Medium |
| 52 |
N-Queens II |
Python |
Hard |
| 53 |
Maximum Subarray |
Python |
Medium |
| 54 |
Spiral Matrix |
Python |
Medium |
| 58 |
Length of Last Word |
Python |
Easy |
| 61 |
Rotate List |
Python |
Medium |
| 64 |
Minimum Path Sum |
Python |
Medium |
| 66 |
Plus One |
Python |
Easy |
| 67 |
Add Binary |
Python |
Easy |
| 69 |
Sqrt(x) |
Python |
Easy |
| 70 |
Climbing Stairs |
Python |
Easy |
| 74 |
Search 2D Matrix |
Python |
Easy |
| 77 |
Combinations |
Python |
Medium |
| 83 |
Remove Duplicates from Sorted List |
Python |
Easy |
| 84 |
Largest Rectangle in Histogram |
Python |
Hard |
| 87 |
Scramble String |
Python |
Hard |
| 88 |
Merge Sorted Array |
Python |
Easy |
| 94 |
Binary Tree Inorder Traversal |
Python |
Easy |
| 95 |
Unique Binary Search Trees II |
Python |
Medium |
| 98 |
Validate Binary Search Tree |
Python1 Python2 |
Medium |
| 100 |
Same Tree |
Python |
Easy |
| 101 |
Symmetric Tree |
Python |
Easy |
| 102 |
Binary Tree Level Order Traversal |
Python |
Medium |
| 104 |
Maximum Depth of Binary Tree |
Python |
Easy |
| 105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Python |
Medium |
| 106 |
Construct Binary Tree from Inorder and Postorder Traversal |
Python |
Medium |
| 108 |
Convert Sorted Array to Binary Search Tree |
Python |
Easy |
| 110 |
Balanced Binary Tree |
Python |
Easy |
| 111 |
Minimum Depth of Binary Tree |
Python |
Easy |
| 112 |
Path Sum |
Python |
Easy |
| 116 |
Populating Next Right Pointers in Each Node |
Python |
Medium |
| 117 |
Populating Next Right Pointers in Each Node II |
Python |
Medium |
| 118 |
Pascal's Triangle |
Python |
Easy |
| 119 |
Pascal's Triangle II |
Python |
Easy |
| 120 |
Triangle |
Python |
Medium |
| 121 |
Best Time to Buy and Sell Stock |
Python |
Easy |
| 125 |
Valid Palindrome |
Python |
Easy |
| 133 |
Clone Graph |
Python |
Medium |
| 136 |
Single Number |
Python |
Easy |
| 138 |
Copy List with Random Pointer |
Python |
Medium |
| 141 |
Linked List Cycle |
Python |
Easy |
| 142 |
Linked List Cycle II |
Python |
Medium |
| 144 |
Binary Tree Preorder Traversal |
Python |
Easy |
| 145 |
Binary Tree Postorder Traversal |
Python |
Easy |
| 150 |
Evaluate Reverse Polish Notation |
Python |
Medium |
| 151 |
Reverse Words in a String |
Python |
Medium |
| 153 |
Find Minimum in Rotated Sorted Array |
Python |
Medium |
| 154 |
Find Minimum in Rotated Sorted Array II |
Python |
Hard |
| 155 |
Min Stack |
Python |
Medium |
| 160 |
Intersection of Two Linked Lists |
Python |
Easy |
| 162 |
Find Peak Element |
Python |
Easy |
| 167 |
Two Sum II - Input Array Is Sorted |
Python |
Medium |
| 168 |
Excel Sheet Column Title |
Python |
Easy |
| 169 |
Majority Element |
Python |
Easy |
| 171 |
Excel Sheet Column Number |
Python |
Easy |
| 189 |
Rotate Array |
Python |
Medium |
| 190 |
Reverse Bits |
Python |
Easy |
| 191 |
Number of 1 Bits |
Python |
Easy |
| 198 |
House Robber |
Python |
Medium |
| 200 |
Number of Islands |
Python |
Medium |
| 202 |
Happy Number |
Python |
Easy |
| 203 |
Remove Linked List Elements |
Python |
Easy |
| 205 |
Isomorphic Strings |
Python |
Easy |
| 206 |
Reverse Linked List |
Python |
Easy |
| 208 |
Implement Trie (Prefix Tree) |
Python |
Medium |
| 209 |
Minimum Size Subarray Sum |
Python |
Medium |
| 211 |
Design Add and Search Words Data Structure |
Python |
Medium |
| 212 |
Word Search II |
Python |
Hard |
| 217 |
Contains Duplicate |
Python |
Easy |
| 219 |
Contains Duplicate II |
Python |
Easy |
| 225 |
Implement Stack using Queues |
Python |
Easy |
| 226 |
Invert Binary Tree |
Python |
Easy |
| 228 |
Summary Ranges |
Python |
Easy |
| 231 |
Power of Two |
Python |
Easy |
| 232 |
Implement Queue using Stacks |
Python |
Easy |
| 234 |
Palindrome Linked List |
Python |
Easy |
| 235 |
Lowest Common Ancestor of a Binary Search Tree |
Python |
Medium |
| 236 |
Lowest Common Ancestor of a Binary Tree |
Python |
Medium |
| 242 |
Valid Anagram |
Python |
Easy |
| 249 |
Perfect Squares |
Python |
Medium |
| 257 |
Binary Tree Paths |
Python |
Easy |
| 258 |
Add Digits |
Python |
Easy |
| 263 |
Ugly Number |
Python |
Easy |
| 268 |
Missing Number |
Python |
Easy |
| 278 |
First Bad Version |
Python |
Easy |
| 283 |
Move Zeroes |
Python |
Easy |
| 287 |
Find the Duplicate Number |
Python |
Medium |
| 290 |
Word Pattern |
Python |
Easy |
| 292 |
Nim Game |
Python |
Easy |
| 297 |
Serialize and Deserialize Binary Tree |
Python |
Hard |
| 303 |
Range Sum Query |
Python |
Easy |
| 326 |
Power of Three |
Python |
Easy |
| 328 |
Odd Even Linked List |
Python |
Medium |
| 336 |
Palindrome Pairs |
Python |
Hard |
| 338 |
Counting Bits |
Python |
Easy |
| 342 |
Power of Four |
Python |
Easy |
| 344 |
Reverse String |
Python |
Easy |
| 345 |
Reverse Vowels of a String |
Python |
Easy |
| 347 |
Top K Frequent Elements |
Python |
Medium |
| 349 |
Intersection of Two Arrays |
Python |
Easy |
| 350 |
Intersection of Two Arrays II |
Python |
Easy |
| 367 |
Valid Perfect Square |
Python |
Easy |
| 374 |
Guess Number Higher or Lower |
Python |
Easy |
| 380 |
Insert Delete GetRandom O(1) |
Python |
Medium |
| 383 |
Ransom Note |
Python |
Easy |
| 387 |
First Unique Character in a String |
Python |
Easy |
| 389 |
Find the Difference |
Python |
Easy |
| 392 |
Is Subsequence |
Python |
Easy |
| 394 |
Decode String |
Python |
Medium |
| 409 |
Longest Palindrome |
Python |
Easy |
| 410 |
Split Array Largest Sum |
Python |
Hard |
| 412 |
Fizz Buzz |
Python |
Easy |
| 414 |
Third Maximum Number |
Python |
Easy |
| 415 |
Add Strings |
Python |
Easy |
| 421 |
Maximum XOR of Two Numbers in an Array |
Python |
Medium |
| 430 |
Flatten a Multilevel Doubly Linked List |
Python |
Medium |
| 434 |
Number of Segments in a String |
Python |
Easy |
| 448 |
Find All Numbers Disappeared in an Array |
Python |
Easy |
| 454 |
4Sum II |
Python |
Medium |
| 461 |
Hamming Distance |
Python |
Easy |
| 485 |
Max Consecutive Ones |
Python |
Easy |
| 494 |
Target Sum |
Python |
Medium |
| 498 |
Diagonal Traverse |
Python |
Medium |
| 509 |
Fibonacci Number |
Python |
Medium |
| 542 |
01 Matrix |
Python |
Easy |
| 557 |
Reverse Words in a String III |
Python |
Easy |
| 561 |
Array Position |
Python |
Easy |
| 566 |
Reshape the Matrix |
Python |
Easy |
| 567 |
Permutation in String |
Python |
Medium |
| 599 |
Minimum Index Sum of Two Lists |
Python |
Easy |
| 617 |
Merge Two Binary Trees |
Python |
Easy |
| 622 |
Design Circular Queue |
Python1, Python2, Python3 |
Medium |
| 648 |
Replace Words |
Python |
Medium |
| 652 |
Find Duplicate Subtrees |
Python |
Medium |
| 653 |
Two Sum IV - Input is a BST |
Python |
Easy |
| 658 |
Find K Closest Elements |
Python |
Easy |
| 677 |
Map Sum Pairs |
Python |
Medium |
| 695 |
Max Area of Island |
Python |
Medium |
| 700 |
Search in a Binary Search Tree |
Python |
Easy |
| 701 |
Insert into a Binary Search Tree |
Python |
Medium |
| 704 |
Binary Search |
Python |
Easy |
| 705 |
Design HashSet |
Python |
Easy |
| 706 |
Design HashMap |
Python |
Easy |
| 707 |
Design Linked List |
Python |
Medium |
| 719 |
Find K-th Smallest Pair Distance |
Python |
Hard |
| 724 |
Find Pivot Index |
Python |
Easy |
| 733 |
Flood Fill |
Python |
Easy |
| 739 |
Daily Temperatures |
Python |
Medium |
| 744 |
Find Smallest Letter Greater Than Target |
Python |
Easy |
| 747 |
Largest Number At Least Twice of Others |
Python |
Easy |
| 752 |
Open the Lock |
Python |
Medium |
| 771 |
Jewels and Stones |
Python |
Easy |
| 779 |
K-th Symbol in Grammar |
Python |
Medium |
| 784 |
Letter Case Permutation |
Python |
Medium |
| 841 |
Keys and Rooms |
Python |
Medium |
| 876 |
Middle of the Linked List |
Python |
Easy |
| 881 |
Boats to Save People |
Python |
Medium |
| 905 |
Sort Array by Parity |
Python |
Easy |
| 912 |
Sort an Array |
Python |
Medium |
| 941 |
Valid Mountain Array |
Python |
Easy |
| 977 |
Squares of a Sorted Array |
Python |
Easy |
| 983 |
Minimum Cost For Tickets |
Python |
Medium |
| 994 |
Number of Steps to Reduce a Number to Zero |
Python |
Medium |
| 1020 |
Number of Enclaves |
Python |
Medium |
| 1051 |
Height Checker |
Python |
Easy |
| 1089 |
Duplicate Zeros |
Python |
Easy |
| 1254 |
Number of Closed Islands |
Python |
Medium |
| 1295 |
Find Numbers with Even Number of Digits |
Python |
Easy |
| 1299 |
Replace Elements with Greatest Element on Right Side |
Python |
Easy |
| 1343 |
Rotting Oranges |
Python |
Hard |
| 1346 |
Check If N and Its Double Exist |
Python |
Easy |
| 1402 |
Reducing Dishes |
Python |
Hard |
| 1444 |
Number of Ways of Cutting a Pizza |
Python |
Hard |
| 1466 |
Reorder Routes to Make All Paths Lead to the City Zero |
Python |
Medium |
| 1480 |
Running Sum of 1d Array |
Python |
Easy |
| 1672 |
Richest Customer Wealth |
Python |
Easy |
| 2236 |
Root Equals Sum of Children |
Python |
Easy |
| 2316 |
Count Unreachable Pairs of Nodes in an Undirected Graph |
Python |
Medium |
| 2348 |
Number of Zero-Filled Subarrays |
Python |
Medium |
| 2360 |
Longest Cycle in a Graph |
Python |
Hard |
| 2405 |
Optimal Partition of String |
Python |
Medium |
| 2439 |
Minimize Maximum of Array |
Python |
Medium |
| 2492 |
Minimum Score of a Path Between Two Cities |
Python |
Medium |
