| 1 |
Two Sum |
Solution |
Easy |
| 2 |
Add Two Numbers |
Solution |
Medium |
| 4 |
Median of Two Sorted Arrays |
Solution |
Hard |
| 5 |
Longest Palindromic Substring |
Solution |
Medium |
| 7 |
Reverse Integer |
Solution |
Easy |
| 9 |
Palindrome Number |
Solution |
Easy |
| 13 |
Roman to Integer |
Solution |
Easy |
| 14 |
Longest Common Prefix |
Solution |
Easy |
| 15 |
3sum |
Solution |
Medium |
| 16 |
3sum Closest |
Solution |
Medium |
| 17 |
Letter Combinations of a Phone Number |
Solution |
Medium |
| 19 |
Remove Nth Node From End of List |
Solution |
Medium |
| 20 |
Valid Parentheses |
Solution |
Easy |
| 21 |
Merge Two Sorted Lists |
Solution |
Easy |
| 22 |
Generate Parentheses |
Solution |
Medium |
| 23 |
Merge k Sorted Lists |
Solution |
Hard |
| 26 |
Remove Duplicates from Sorted Array |
Solution |
Easy |
| 27 |
Remove Element |
Solution |
Easy |
| 28 |
Implement strStr() |
Solution |
Easy |
| 33 |
Search in Rotated Sorted Array |
Solution |
Medium |
| 34 |
Find First and Last Position of Element in Sorted Array |
Solution |
Medium |
| 35 |
Search Insert Position |
Solution |
Easy |
| 38 |
Count and Say |
Solution |
Easy |
| 42 |
Trapping Rain Water |
Solution |
Hard |
| 46 |
Permutations |
Solution |
Medium |
| 47 |
Permutations II |
Solution |
Medium |
| 48 |
Rotate Image |
Solution |
Medium |
| 49 |
Group Anagrams |
Solution |
Medium |
| 51 |
N-Queens |
Solution |
Hard |
| 52 |
N-Queens II |
Solution |
Hard |
| 53 |
Maximum Subarray |
Solution |
Easy |
| 55 |
Jump Game |
Solution |
Medium |
| 58 |
Length of Last Word |
Solution |
Easy |
| 62 |
Unique Paths |
Solution |
Medium |
| 63 |
Unique Paths II |
Solution |
Medium |
| 66 |
Plus One |
Solution |
Easy |
| 67 |
Add Binary |
Solution |
Easy |
| 69 |
Sqrt(x) |
Solution |
Easy |
| 70 |
Climbing Stairs |
Solution |
Easy |
| 73 |
Set Matrix Zeroes |
Solution |
Medium |
| 78 |
Subsets |
Solution |
Medium |
| 80 |
Remove Duplicates from Sorted Array II |
Solution |
Medium |
| 81 |
Search in Rotated Sorted Array II |
Solution |
Medium |
| 82 |
Remove Duplicates from Sorted List II |
Solution |
Medium |
| 83 |
Remove Duplicates from Sorted List |
Solution |
Easy |
| 88 |
Merge Sorted Array |
Solution |
Easy |
| 90 |
Subsets II |
Solution |
Medium |
| 92 |
Reverse Linked List II |
Solution |
Medium |
| 94 |
Binary Tree Inorder Traversal |
Solution |
Medium |
| 98 |
Validate Binary Search Tree |
Solution |
Medium |
| 100 |
Same Tree |
Solution |
Easy |
| 101 |
Symmetric Tree |
Solution |
Easy |
| 102 |
Binary Tree Level Order Traversal |
Solution |
Medium |
| 104 |
Maximum Depth of Binary Tree |
Solution |
Easy |
| 107 |
Binary Tree Level Order Traversal II |
Solution |
Easy |
| 108 |
Convert Sorted Array to Binary Search Tree |
Solution |
Easy |
| 110 |
Balanced Binary Tree |
Solution |
Easy |
| 111 |
Minimum Depth of Binary Tree |
Solution |
Easy |
| 118 |
Pascal's Triangle |
Solution |
Easy |
| 119 |
Pascal's Triangle II |
Solution |
Easy |
| 121 |
Best Time to Buy and Sell Stock |
Solution |
Easy |
| 122 |
Best Time to Buy and Sell Stock II |
Solution |
Easy |
| 125 |
Valid Palindrome |
Solution |
Easy |
| 127 |
Word Ladder |
Solution |
Medium |
| 136 |
Single Number |
Solution |
Easy |
| 139 |
Word Break |
Solution |
Medium |
| 141 |
Linked List Cycle |
Solution |
Easy |
| 142 |
Linked List Cycle II |
Solution |
Medium |
| 143 |
Reorder List |
Solution |
Medium |
| 144 |
Binary Tree Preorder Traversal |
Solution |
Medium |
| 145 |
Binary Tree Postorder Traversal |
Solution |
Hard |
| 146 |
LRU Cache |
Solution |
Medium |
| 148 |
Sort List |
Solution |
Medium |
| 149 |
Max Points on a Line |
Solution |
Hard |
| 151 |
Reverse Words in a String |
Solution |
Medium |
| 155 |
Min Stack |
Solution |
Easy |
| 160 |
Intersection of Two linked Lists |
Solution |
Easy |
| 162 |
Find Peak Element |
Solution |
Medium |
| 167 |
Two Sum II - Input array is sorted |
Solution |
Easy |
| 168 |
Excel Sheet Column Title |
Solution |
Easy |
| 169 |
Majority Element |
Solution |
Easy |
| 171 |
Excel Sheet Column Number |
Solution |
Easy |
| 172 |
Factorial Trailing Zeroes |
Solution |
Easy |
| 175 |
Combine Two Tables |
Solution |
Easy |
| 176 |
Second Highest Salary |
Solution |
Easy |
| 177 |
Nth Highest Salary |
Solution |
Medium |
| 178 |
Rank Scores |
Solution |
Medium |
| 180 |
Consecutive Numbers |
Solution |
Medium |
| 181 |
Employees Earning More Than Their Managers |
Solution |
Easy |
| 182 |
Duplicate Emails |
Solution |
Easy |
| 183 |
Customers Who Never Order |
Solution |
Easy |
| 184 |
Department Highest Salary |
Solution |
Medium |
| 185 |
Department Top Three Salaries |
Solution |
Hard |
| 189 |
Rotate Array |
Solution |
Easy |
| 190 |
Reverse Bits |
Solution |
Easy |
| 191 |
Number of 1 Bits |
Solution |
Easy |
| 196 |
Delete Duplicate Emails |
Solution |
Easy |
| 197 |
Rising Temperature |
Solution |
Easy |
| 198 |
House Robber |
Solution |
Easy |
| 200 |
Number of Islands |
Solution |
Medium |
| 202 |
Happy Number |
Solution |
Easy |
| 203 |
Remove Linked List Elements |
Solution |
Easy |
| 204 |
Count Primes |
Solution |
Easy |
| 206 |
Reverse Linked List |
Solution |
Easy |
| 207 |
Course Schedule |
Solution |
Medium |
| 208 |
Implement Trie (Prefix Tree) |
Solution |
Medium |
| 210 |
Course Schedule II |
Solution |
Medium |
| 217 |
Contains Duplicate |
Solution |
Easy |
| 226 |
Invert Binary Tree |
Solution |
Easy |
| 231 |
Power of Two |
Solution |
Easy |
| 232 |
Implement Queue using Stacks |
Solution |
Easy |
| 234 |
Palindrome Linked List |
Solution |
Easy |
| 235 |
Lowest Common Ancestor of a Binary Search Tree |
Solution |
Easy |
| 236 |
Lowest Common Ancestor of a Binary Tree |
Solution |
Medium |
| 237 |
Delete Node in a Linked List |
Solution |
Easy |
| 238 |
Product of Array Except Self |
Solution |
Medium |
| 239 |
Sliding Window Maximum |
Solution |
Hard |
| 240 |
Search a 2D Matrix II |
Solution |
Medium |
| 242 |
Valid Anagram |
Solution |
Easy |
| 262 |
Trips and Users |
Solution |
Hard |
| 263 |
Ugly Number |
Solution |
Easy |
| 264 |
Ugly Number II |
Solution |
Medium |
| 268 |
Missing Number |
Solution |
Easy |
| 273 |
Integer to English Words |
Solution |
Hard |
| 278 |
First Bad Version |
Solution |
Easy |
| 283 |
Move Zeroes |
Solution |
Easy |
| 290 |
Word Pattern |
Solution |
Easy |
| 292 |
Nim Game |
Solution |
Easy |
| 295 |
Find Median from Data Stream |
Solution |
Hard |
| 300 |
Longest Increasing Subsequence |
Solution |
Medium |
| 303 |
Range Sum Query - Immutable |
Solution |
Easy |
| 309 |
Best Time to Buy and Sell Stock with Cooldown |
Solution |
Medium |
| 326 |
Power of Three |
Solution |
Easy |
| 328 |
Odd Even Linked List |
Solution |
Medium |
| 342 |
Power of Four |
Solution |
Easy |
| 344 |
Reverse String |
Solution |
Easy |
| 347 |
Top K Frequent Elements |
Solution |
Medium |
| 349 |
Intersection of Two Arrays |
Solution |
Easy |
| 350 |
Intersection of Two Arrays II |
Solution |
Easy |
| 354 |
Russian Doll Envelopes |
Solution |
Hard |
| 367 |
Valid Perfect Square |
Solution |
Easy |
| 371 |
Sum of Two Integers |
Solution |
Easy |
| 380 |
Insert Delete GetRandom O(1) |
Solution |
Medium |
| 381 |
Insert Delete GetRandom O(1) - Duplicates allowed |
Solution |
Hard |
| 383 |
Ransom Note |
Solution |
Easy |
| 384 |
Shuffle an Array |
Solution |
Medium |
| 387 |
First Unique Character in a String |
Solution |
Easy |
| 389 |
Find the Difference |
Solution |
Easy |
| 412 |
Fizz Buzz |
Solution |
Easy |
| 414 |
Third Maximum Number |
Solution |
Easy |
| 429 |
N-ary Tree Level Order Traversal |
Solution |
Easy |
| 437 |
Path Sum III |
Solution |
Easy |
| 442 |
Find All Duplicates in an Array |
Solution |
Medium |
| 443 |
String Compression |
Solution |
Easy |
| 445 |
Add Two Numbers II |
Solution |
Medium |
| 448 |
Find All Numbers Disappeared in an Array |
Solution |
Easy |
| 454 |
4Sum II |
Solution |
Medium |
| 461 |
Hamming Distance |
Solution |
Easy |
| 470 |
Implement Rand10() Using Rand7() |
Solution |
Medium |
| 477 |
Total Hamming Distance |
Solution |
Medium |
| 480 |
Sliding Window Median |
Solution |
Hard |
| 500 |
Keyboard Row |
Solution |
Easy |
| 509 |
Fibonacci Number |
Solution |
Easy |
| 516 |
Longest Palindromic Subsequence |
Solution |
Medium |
| 518 |
Coin Change 2 |
Solution |
Medium |
| 520 |
Detect Capital |
Solution |
Easy |
| 525 |
Contiguous Array |
Solution |
Medium |
| 543 |
Diameter of Binary Tree |
Solution |
Easy |
| 559 |
Maximum Depth of N-ary Tree |
Solution |
Easy |
| 560 |
Subarray Sum Equals K |
Solution |
Medium |
| 572 |
Subtree of Another Tree |
Solution |
Easy |
| 581 |
Shortest Unsorted Continuous Subarray |
Solution |
Easy |
| 589 |
N-ary Tree Preorder Traversal |
Solution |
Easy |
| 590 |
N-ary Tree Postorder Traversal |
Solution |
Easy |
| 595 |
Big Countries |
Solution |
Easy |
| 596 |
Classes More Than 5 Students |
Solution |
Easy |
| 601 |
Human Traffic of Stadium |
Solution |
Hard |
| 617 |
Merge Two Binary Trees |
Solution |
Easy |
| 620 |
Not Boring Movies |
Solution |
Easy |
| 626 |
Exchange Seats |
Solution |
Medium |
| 627 |
Swap Salary |
Solution |
Easy |
| 692 |
Top K Frequent Words |
Solution |
Medium |
| 695 |
Max Area of Island |
Solution |
Medium |
| 703 |
Kth Largest Element in a Stream |
Solution |
Easy |
| 704 |
Binary Search |
Solution |
Easy |
| 706 |
Design HashMap |
Solution |
Easy |
| 707 |
Design Linked List |
Solution |
Easy |
| 709 |
To Lower Case |
Solution |
Easy |
| 733 |
Flood Fill |
Solution |
Easy |
| 771 |
Jewels and Stones |
Solution |
Easy |
| 895 |
Maximum Frequency Stack |
Solution |
Hard |
| 912 |
Sort an Array |
Solution |
Medium |
| 976 |
Largest Perimeter Triangle |
Solution |
Easy |
| 1010 |
Pairs of Songs With Total Durations Divisible by 60 |
Solution |
Easy |
| 1092 |
Shortest Common Supersequence |
Solution |
Hard |
| 1114 |
Print in Order |
Solution |
Easy |
| 1115 |
Print FooBar Alternately |
Solution |
Medium |
| 1116 |
Print Zero Even Odd |
Solution |
Medium |
| 1117 |
Building H2O |
Solution |
Medium |
| 1139 |
Largest 1-Bordered Square |
Solution |
Medium |
| 1179 |
Reformat Department Table |
Solution |
Easy |
| 1195 |
Fizz Buzz Multithreaded |
Solution |
Medium |
| 1207 |
Unique Number of Occurrences |
Solution |
Easy |
