| 1 |
Two Sum |
Python |
Easy |
| 2 |
Add Two Numbers |
Python |
Medium |
| 3 |
Longest Substring Without Repeating Characters |
Python |
Medium |
| 4 |
Median of Two Sorted Arrays |
Python |
Hard |
| 5 |
Longest Palindromic Substring |
Python |
Medium |
| 6 |
ZigZag Conversion |
Python |
Medium |
| 7 |
Reverse Integer |
Python |
Easy |
| 8 |
String to Integer (atoi) |
Python |
Medium |
| 9 |
Palindrome Number |
Python |
Easy |
| 11 |
Container With Most Water |
Python |
Medium |
| 12 |
Integer to Roman |
Python |
Medium |
| 13 |
Roman to Integer |
Python |
Easy |
| 14 |
Longest Common Prefix |
Python |
Easy |
| 15 |
3Sum |
Python |
Medium |
| 16 |
3Sum Closest |
Python |
Medium |
| 17 |
Letter Combinations of a Phone Number |
Python |
Medium |
| 18 |
4Sum |
Python |
Medium |
| 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 |
| 25 |
Reverse Nodes in k-Group |
Python |
Hard |
| 26 |
Remove Duplicates from Sorted Array |
Python |
Easy |
| 27 |
Remove Element |
Python |
Easy |
| 28 |
Implement strStr() |
Python |
Easy |
| 29 |
Divide Two Integers |
Python |
Medium |
| 31 |
Next Permutation |
Python |
Medium |
| 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 |
| 38 |
Count and Say |
Python |
Easy |
| 39 |
Combination Sum |
Python |
Medium |
| 40 |
Combination Sum II |
Python |
Medium |
| 43 |
Multiply Strings |
Python |
Medium |
| 46 |
Permutations |
Python |
Medium |
| 47 |
Permutations II |
Python |
Medium |
| 48 |
Rotate Image |
Python |
Medium |
| 49 |
Group Anagrams |
Python |
Medium |
| 50 |
Pow(x, n) |
Python |
Medium |
| 53 |
Maximum Subarray |
Python |
Easy |
| 54 |
Spiral Matrix |
Python |
Medium |
| 55 |
Jump Game |
Python |
Medium |
| 56 |
Merge Intervals |
Python |
Medium |
| 58 |
Length of Last Word |
Python |
Easy |
| 59 |
Spiral Matrix II |
Python |
Medium |
| 60 |
Permutation Sequence |
Python |
Medium |
| 61 |
Rotate List |
Python |
Medium |
| 62 |
Unique Paths |
Python |
Medium |
| 63 |
Unique Paths II |
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 |
| 71 |
Simplify Path |
Python |
Medium |
| 73 |
Set Matrix Zeroes |
Python |
Medium |
| 74 |
Search a 2D Matrix |
Python |
Medium |
| 75 |
Sort Colors |
Python |
Medium |
| 77 |
Combinations |
Python |
Medium |
| 78 |
Subsets |
Python |
Medium |
| 79 |
Word Search |
Python |
Medium |
| 80 |
Remove Duplicates from Sorted Array II |
Python |
Medium |
| 81 |
Search in Rotated Sorted Array II |
Python |
Medium |
| 82 |
Remove Duplicates from Sorted List II |
Python |
Medium |
| 83 |
Remove Duplicates from Sorted List |
Python |
Easy |
| 86 |
Partition List |
Python |
Medium |
| 88 |
Merge Sorted Array |
Python |
Easy |
| 89 |
Gray Code |
Python |
Medium |
| 90 |
Subsets II |
Python |
Medium |
| 91 |
Decode Ways |
Python |
Medium |
| 92 |
Reverse Linked List II |
Python |
Medium |
| 93 |
Restore IP Addresses |
Python |
Medium |
| 94 |
Binary Tree Inorder Traversal |
Python |
Medium |
| 100 |
Same Tree |
Python |
Easy |
| 101 |
Symmetric Tree |
Python |
Easy |
| 102 |
Binary Tree Level Order Traversal |
Python |
Medium |
| 103 |
Binary Tree Zigzag Level Order Traversal |
Python |
Medium |
| 104 |
Maximum Depth of Binary Tree |
Python |
Easy |
| 107 |
Binary Tree Level Order Traversal II |
Python |
Easy |
| 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 |
| 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 |
| 122 |
Best Time to Buy and Sell Stock II |
Python |
Easy |
| 125 |
Valid Palindrome |
Python |
Easy |
| 136 |
Single Number |
Python |
Easy |
| 141 |
Linked List Cycle |
Python |
Easy |
| 144 |
Binary Tree Preorder Traversal |
Python |
Medium |
| 148 |
Sort List |
Python |
Medium |
| 155 |
Min Stack |
Python |
Easy |
| 157 |
Read N Characters Given Read4 |
Python |
Easy |
| 160 |
Intersection of Two Linked Lists |
Python |
Easy |
| 167 |
Two Sum II - Input array is sorted |
Python |
Easy |
| 168 |
Excel Sheet Column Title |
Python |
Easy |
| 169 |
Majority Element |
Python |
Easy |
| 170 |
Two Sum III - Data structure design |
Python |
Easy |
| 171 |
Excel Sheet Column Number |
Python |
Easy |
| 172 |
Factorial Trailing Zeroes |
Python |
Easy |
| 175 |
Combine Two Tables |
SQL |
Easy |
| 176 |
Second Highest Salary |
SQL |
Easy |
| 181 |
Employees Earning More Than Their Managers |
SQL |
Easy |
| 182 |
Duplicate Emails |
SQL |
Easy |
| 183 |
Customers Who Never Order |
SQL |
Easy |
| 189 |
Rotate Array |
Python |
Easy |
| 190 |
Reverse Bits |
Python |
Easy |
| 191 |
Number of 1 Bits |
Python |
Easy |
| 196 |
Delete Duplicate Emails |
SQL |
Easy |
| 197 |
Rising Temperature |
SQL |
Easy |
| 198 |
House Robber |
Python |
Easy |
| 200 |
Number of Islands |
Python |
Medium |
| 202 |
Happy Number |
Python |
Easy |
| 203 |
Remove Linked List Elements |
Python |
Easy |
| 204 |
Count Primes |
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 |
| 217 |
Contains Duplicate |
Python |
Easy |
| 219 |
Contains Duplicate II |
Python |
Easy |
| 225 |
Implement Stack using Queues |
Python |
Easy |
| 226 |
Invert Binary Tree |
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 |
Easy |
| 237 |
Delete Node in a Linked List |
Python |
Easy |
| 238 |
Product of Array Except Self |
Python |
Medium |
| 242 |
Valid Anagram |
Python |
Easy |
| 243 |
Shortest Word Distance |
Python |
Easy |
| 246 |
Strobogrammatic Number |
Python |
Easy |
| 252 |
Meeting Rooms |
Python |
Easy |
| 256 |
Paint House |
Python |
Easy |
| 257 |
Binary Tree Paths |
Python |
Easy |
| 258 |
Add Digits |
Python |
Easy |
| 261 |
Graph Valid Tree |
Python |
Medium |
| 263 |
Ugly Number |
Python |
Easy |
| 266 |
Palindrome Permutation |
Python |
Easy |
| 268 |
Missing Number |
Python |
Easy |
| 270 |
Closest Binary Search Tree Value |
Python |
Easy |
| 276 |
Paint Fence |
Python |
Easy |
| 278 |
First Bad Version |
Python |
Easy |
| 283 |
Move Zeroes |
Python |
Easy |
| 290 |
Word Pattern |
Python |
Easy |
| 292 |
Nim Game |
Python |
Easy |
| 293 |
Flip Game |
Python |
Easy |
| 303 |
Range Sum Query - Immutable |
Python |
Easy |
| 323 |
Number of Connected Components in an Undirected Graph |
Python |
Medium |
| 325 |
Maximum Size Subarray Sum Equals k |
Pyhon |
Medium |
| 326 |
Power of Three |
Python |
Easy |
| 339 |
Nested List Weight Sum |
Python |
Easy |
| 342 |
Power of Four |
Python |
Easy |
| 344 |
Reverse String |
Python |
Easy |
| 345 |
Reverse Vowels of a String |
Python |
Easy |
| 346 |
Moving Average from Data Stream |
Python |
Easy |
| 349 |
Intersection of Two Arrays |
Python |
Easy |
| 350 |
Intersection of Two Arrays II |
Python |
Easy |
| 359 |
Logger Rate Limiter |
Python |
Easy |
| 367 |
Valid Perfect Square |
Python |
Easy |
| 371 |
Sum of Two Integers |
Python |
Easy |
| 374 |
Guess Number Higher or Lower |
Python |
Easy |
| 383 |
Ransom Note |
Python |
Easy |
| 387 |
First Unique Character in a String |
Python |
Easy |
| 389 |
Find the Difference |
Python |
Easy |
| 400 |
Nth Digit |
Python |
Easy |
| 401 |
Binary Watch |
Python |
Easy |
| 404 |
Sum of Left Leaves |
Python |
Easy |
| 405 |
Convert a Number to Hexadecimal |
Python |
Easy |
| 408 |
Valid Word Abbreviation |
Python |
Easy |
| 409 |
Longest Palindrome |
Python |
Easy |
| 412 |
Fizz Buzz |
Python |
Easy |
| 414 |
Third Maximum Number |
Python |
Easy |
| 415 |
Add Strings |
Python |
Easy |
| 416 |
Partition Equal Subset Sum |
Python |
Medium |
| 422 |
Valid Word Square |
Python |
Easy |
| 427 |
Construct Quad Tree |
Python |
Easy |
| 429 |
N-ary Tree Level Order Traversal |
Python |
Easy |
| 434 |
Number of Segments in a String |
Python |
Easy |
| 437 |
Path Sum III |
Python |
Easy |
| 438 |
Find All Anagrams in a String |
Python |
Easy |
| 441 |
Arranging Coins |
Python |
Easy |
| 443 |
String Compression |
Python |
Easy |
| 447 |
Number of Boomerangs |
Python |
Easy |
| 448 |
Find All Numbers Disappeared in an Array |
Python |
Easy |
| 453 |
Minimum Moves to Equal Array Elements |
Python |
Easy |
| 455 |
Assign Cookies |
Python |
Easy |
| 458 |
Poor Pigs |
Python |
Easy |
| 459 |
Repeated Substring Pattern |
Python |
Easy |
| 461 |
Hamming Distance |
Python |
Easy |
| 463 |
Island Perimeter |
Python |
Easy |
| 468 |
Validate IP Address |
Python |
Medium |
| 475 |
Heaters |
Python |
Easy |
| 476 |
Number Complement |
Python |
Easy |
| 479 |
Largest Palindrome Product |
Python |
Easy |
| 482 |
License Key Formatting |
Python |
Easy |
| 485 |
Max Consecutive Ones |
Python |
Easy |
| 492 |
Construct the Rectangle |
Python |
Easy |
| 496 |
Next Greater Element I |
Python |
Easy |
| 500 |
Keyboard Row |
Python |
Easy |
| 501 |
Find Mode in Binary Search Tree |
Python |
Easy |
| 504 |
Base 7 |
Python |
Easy |
| 506 |
Relative Ranks |
Python |
Easy |
| 507 |
Perfect Number |
Python |
Easy |
| 520 |
Detect Capital |
Python |
Easy |
| 521 |
Longest Uncommon Subsequence I |
Python |
Easy |
| 530 |
Minimum Absolute Difference in BST |
Python |
Easy |
| 532 |
K-diff Pairs in an Array |
Python |
Easy |
| 538 |
Convert BST to Greater Tree |
Python |
Easy |
| 541 |
Reverse String II |
Python |
Easy |
| 543 |
Diameter of Binary Tree |
Python |
Easy |
| 551 |
Student Attendance Record I |
Python |
Easy |
| 557 |
Reverse Words in a String III |
Python |
Easy |
| 558 |
Quad Tree Intersection |
Python |
Easy |
| 559 |
Maximum Depth of N-ary Tree |
Python |
Easy |
| 560 |
Subarray Sum Equals K |
Python |
Medium |
| 561 |
Array Partition I |
Python |
Easy |
| 563 |
Binary Tree Tilt |
Python |
Easy |
| 566 |
Reshape the Matrix |
Python |
Easy |
| 572 |
Subtree of Another Tree |
Python |
Easy |
| 575 |
Distribute Candies |
Python |
Easy |
| 577 |
Employee Bonus |
SQL |
Easy |
| 581 |
Shortest Unsorted Continuous Subarray |
Python |
Easy |
| 584 |
Find Customer Referee |
SQL |
Easy |
| 586 |
Customer Placing the Largest Number of Orders |
SQL |
Easy |
| 589 |
N-ary Tree Preorder Traversal |
Python |
Easy |
| 590 |
N-ary Tree Postorder Traversal |
Python |
Easy |
| 594 |
Longest Harmonious Subsequence |
Python |
Easy |
| 595 |
Big Countries |
SQL |
Easy |
| 596 |
Classes More Than 5 Students |
SQL |
Easy |
| 597 |
Friend Requests I: Overall Acceptance Rate |
SQL |
Easy |
| 598 |
Range Addition II |
Python |
Easy |
| 599 |
Minimum Index Sum of Two Lists |
Python |
Easy |
| 603 |
Consecutive Available Seats |
SQL |
Easy |
| 604 |
Design Compressed String Iterator |
Python |
Easy |
| 605 |
Can Place Flowers |
Python |
Easy |
| 606 |
Construct String from Binary Tree |
Python |
Easy |
| 607 |
Sales Person |
SQL |
Easy |
| 610 |
Triangle Judgement |
SQL |
Easy |
| 613 |
Shortest Distance in a Line |
SQL |
Easy |
| 617 |
Merge Two Binary Trees |
Python |
Easy |
| 619 |
Biggest Single Number |
SQL |
Easy |
| 620 |
Not Boring Movies |
SQL |
Easy |
| 624 |
Maximum Distance in Arrays |
Python |
Easy |
| 627 |
Swap Salary |
SQL |
Easy |
| 628 |
Maximum Product of Three Numbers |
Python |
Easy |
| 633 |
Sum of Square Numbers |
Python |
Easy |
| 637 |
Average of Levels in Binary Tree |
Python |
Easy |
| 643 |
Maximum Average Subarray I |
Python |
Easy |
| 645 |
Set Mismatch |
Python |
Easy |
| 653 |
Two Sum IV - Input is a BST |
Python |
Easy |
| 657 |
Robot Return to Origin |
Python |
Easy |
| 661 |
Image Smoother |
Python |
Easy |
| 665 |
Non-decreasing Array |
Python |
Easy |
| 669 |
Trim a Binary Search Tree |
Python |
Easy |
| 671 |
Second Minimum Node In a Binary Tree |
Python |
Easy |
| 674 |
Longest Continuous Increasing Subsequence |
Python |
Easy |
| 680 |
Valid Palindrome II |
Python |
Easy |
| 682 |
Baseball Game |
Python |
Easy |
| 686 |
Repeated String Match |
Python |
Easy |
| 687 |
Longest Univalue Path |
Python |
Easy |
| 690 |
Employee Importance |
Python |
Easy |
| 693 |
Binary Number with Alternating Bits |
Python |
Easy |
| 695 |
Max Area of Island |
Python |
Easy |
| 696 |
Count Binary Substrings |
Python |
Easy |
| 713 |
Subarray Product Less Than K |
Python |
Medium |
| 987 |
Vertical Order Traversal of a Binary Tree |
Python |
Medium |
| 1052 |
Grumpy Bookstore Owner |
Python |
Medium |
| 1151 |
Minimum Swaps to Group All 1's Together |
Python |
Medium |
| 1155 |
Number of Dice Nolls with Target Sum |
Python |
Medium |
| 1197 |
Minimum Knight Moves |
Python |
Medium |
| 1245 |
Tree Diameter |
Python |
Medium |
| 1492 |
The kth Factor of n |
Python |
Medium |
| 1676 |
Lowest Common Ancestor of a Binary Tree IV |
Python |
Medium |
| 2355 |
Maximum Number of Books You Can Take |
Python |
Hard |
| 2405 |
Optimal Partition of String |
Python |
Medium |
| 2422 |
Merge Operations to Turn Array Into a Palindrome |
Python |
Medium |
| 2534 |
Time Taken to Cross the Door |
Python |
Hard |