| 1 |
Two Sum |
   |
Easy |
|
| 7 |
Reverse Integer |
|
Easy |
|
| 9 |
Palindrome Number |
|
Easy |
|
| 11 |
Container With Most Water |
|
Medium |
|
| 15 |
3Sum |
 |
Medium |
|
| 20 |
Valid Parentheses |
|
Easy |
|
| 21 |
Merge Two Sorted Lists |
|
Easy |
|
| 23 |
Merge k Sorted Lists |
|
Hard |
|
| 26 |
Remove Duplicates from Sorted Array |
|
Easy |
|
| 27 |
Remove Element |
|
Easy |
|
| 28 |
Implement strStr() |
|
Easy |
|
| 34 |
Find First and Last Position of Element in Sorted Array |
|
Medium |
|
| 35 |
Search Insert Position |
|
Easy |
|
| 38 |
Count and Say |
|
Easy |
|
| 53 |
Maximum Subarray |
|
Easy |
|
| 58 |
Length of Last Word |
|
Easy |
|
| 66 |
Plus One |
|
Easy |
|
| 67 |
Add Binary |
|
Easy |
|
| 69 |
Sqrt(x) |
|
Easy |
|
| 70 |
Climbing Stairs |
|
Easy |
|
| 79 |
Word Search |
|
Medium |
|
| 83 |
Remove Duplicates from Sorted List |
 |
Easy |
|
| 88 |
Merge Sorted Array |
|
Easy |
|
| 100 |
Same Tree |
 |
Easy |
Tree |
| 101 |
Symmetric Tree |
|
Easy |
|
| 102 |
Binary Tree Level Order Traversal |
|
Easy |
|
| 104 |
Maximum Depth of Binary Tree |
|
Easy |
Tree |
| 105 |
Construct Binary Tree from Preorder and Inorder Traversal |
|
Easy |
|
| 107 |
Binary Tree Level Order Traversal II |
|
Easy |
|
| 108 |
Convert Sorted Array to Binary Search tree |
|
Easy |
Recursion |
| 111 |
Minimum Depth of Binary Tree |
|
Easy |
Tree |
| 112 |
Path Sum |
|
Easy |
Tree |
| 113 |
Path Sum II |
|
Medium |
Tree |
| 116 |
Populating Next Right Pointers in Each Node |
|
Medium |
Tree |
| 117 |
Populating Next Right Pointers in Each Node II |
|
Medium |
Tree |
| 118 |
Pascal's Triangle |
|
Easy |
|
| 119 |
Pascal's Triangle II |
|
Easy |
|
| 121 |
Best Time to Buy and Sell Stock |
|
Easy |
|
| 122 |
Best Time to Buy and Sell Stock II |
|
Easy |
|
| 125 |
Valid Palindrome |
|
Easy |
|
| 155 |
Min Stack |
|
Easy |
|
| 160 |
Intersection of Two Linked Lists |
|
Easy |
|
| 167 |
Two Sum II - Input array is sorted |
|
Easy |
|
| 168 |
Excel Sheet column Title |
|
Easy |
|
| 169 |
Majority Element |
|
Easy |
|
| 171 |
Excel Sheet Column Number |
|
Easy |
|
| 172 |
Factorial Trailing Zeroes |
|
Easy |
|
| 189 |
Rotate Array |
|
Easy |
|
| 190 |
Reverse Bits |
|
Easy |
|
| 191 |
Number of 1 Bits |
|
Easy |
|
| 198 |
House Robber |
|
Easy |
|
| 199 |
Binary Tree Right Side View |
|
Medium |
|
| 202 |
Happy Number |
|
Easy |
|
| 203 |
Remove Linked List Elements |
|
Easy |
|
| 204 |
Count Primes |
|
Easy |
|
| 205 |
Isomorphic Strings |
|
Easy |
|
| 206 |
Reverse Linked List |
|
Easy |
|
| 217 |
Contains Duplicate |
|
Easy |
|
| 219 |
Contains Duplicate II |
|
Easy |
|
| 225 |
Implement Stack using Queues |
|
Easy |
|
| 226 |
Invert Binary Tree |
|
Easy |
|
| 228 |
Summary Ranges |
|
Easy |
|
| 231 |
Power of Two |
|
Easy |
|
| 232 |
Implement Queue using Stacks |
|
Easy |
|
| 234 |
Palindrome Linked List |
|
Easy |
|
| 235 |
Lowest Common Ancestor of a Binary Search Tree |
|
Easy |
|
| 237 |
Delete Node in a Linked List |
|
Easy |
|
| 242 |
Valid Anagram |
|
Easy |
|
| 257 |
Binary Tree Paths |
|
Easy |
|
| 258 |
Add Digits |
|
Easy |
|
| 263 |
Ugly Number |
|
Easy |
|
| 264 |
Ugly Number II |
|
Medium |
|
| 268 |
Missing Number |
|
Easy |
|
| 278 |
First Bad Version |
|
Easy |
|
| 283 |
Move Zeroes |
|
Easy |
|
| 295 |
⭐ Find Median from Data Stream |
|
Hard |
|
| 297 |
⭐ Serialize and Deserialize Binary Tree |
|
Hard |
|
| 303 |
Range Sum Query - Immutable |
|
Easy |
|
| 400 |
Nth Digit |
|
Medium |
|
| 414 |
Third Maximum Number |
|
Easy |
|
| 426 |
Convert Binary Search Tree to Sorted Doubly Linked List |
|
Medium |
|
| 429 |
N-ary Tree Level Order Traversal |
|
Medium |
|
| 448 |
Find All Numbers Disappeared In An Array |
|
Easy |
|
| 485 |
Max Consecutive Ones |
|
Easy |
|
| 509 |
Fibonacci Number |
|
Easy |
|
| 515 |
Find Largest Value in Each Tree Row |
|
Medium |
|
| 561 |
Array Partition I |
|
Easy |
|
| 566 |
Reshape the Matrix |
|
Easy |
|
| 581 |
Shortest Unsorted Continuous Subarray |
|
Easy |
|
| 589 |
N-ary Tree Preorder Traversal |
|
Easy |
Tree |
| 605 |
Can Place Flowers |
|
Easy |
|
| 606 |
Construct String from Binary Tree |
|
Easy |
|
| 617 |
Merge Two Binary Trees |
|
Easy |
Tree |
| 628 |
Maximum Product of Three Numbers |
|
Easy |
|
| 637 |
Average of Levels in Binary Tree |
|
Easy |
|
| 746 |
Min Cost Climbing Stairs |
|
Easy |
|
| 747 |
Largest Number At Least Twice of Others |
|
Easy |
|
| 766 |
Toeplitz Matrix |
|
Easy |
|
| 830 |
Positions of Large Groups |
|
Easy |
|
| 832 |
Flipping an Image |
|
Easy |
|
| 867 |
Transpose Matrix |
|
Easy |
|
| 905 |
Sort Array By Parity |
|
Easy |
|
| 922 |
Sort Array By Parity II |
|
Easy |
|
| 1022 |
Sum of Root To Leaf Binary Numbers |
|
Easy |
Tree |
| 1025 |
Divisor Game |
|
Easy |
|
| 1207 |
[Unique Number of Occurrences][1207] |
|
Easy |
|
