- 1. Two Sum
- 7. Reverse Integer
- 17. Letter Combination of a Phone Number
- 20. Valid Parentheses
- 26. Remove Duplicates From Sorted Array
- 27. Remove Element
- 66. Plus One
- 67. Add Binary
- 70. Climbing Stairs
- 91. Decode Ways
- 102. Binary Tree Level Order Traversal
- 108. Convert Sorted Array to Binary Search Tree
- 112. Path Sum
- 121. Best Time to Buy and Sell Stock
- 125. Valid Palindrome
- 136. Single Number
- 137. Single Number II
- 169. Majority Element
- 200. Number of Islands
- 206. Reverse Linked List
- 215. Kth Largest Element in an Array
- 217. Contains Duplicate
- 219. Contains Duplicate II
- 231. Power of Two
- 235. Lowest Common Ancestor of a Binary Search Tree
- 242. Valid Anagram
- 263. Ugly Number
- 268. Missing Number
- 278. First Bad Version
- 283. Move Zeros
- 342. Power of Four
- 344. Reverse String
- 349. Intersection of Two Array
- 387. First Unique Character in a String
- 389. Find the Difference
- 404. Sum of Left Leaves
- 412. Fizz Buzz
- 448. Find All Numbers Disappeared in an Array
- 461. Hamming Distance
- 476. Number Complement
- 657. Robot Return to Origin
- 693. Binary Number with Alternating Bits
- 771. Jewels and Stones
- 832. Flipping an Image
- 844. Backspace String Compare
- 896. Monotonic Array
- 973. K Closest Points to Origin