Completed Problems:
- 0001 - Two Sum
- 0002 - Add Two Numbers
- 0003 - Longest Substring Without Repeating Characters
- 0009 - Palindrome Number
- 0013 - Roman to Integer
- 0014 - Longest Common Prefix
- 0017 - Letter Combinations of a Phone Number
- 0020 - Valid Parentheses
- 0021 - Merge Two Sorted Lists
- 0026 - Remove Duplicates from Sorted Array
- 0027 - Remove Element
- 0029 - Divide Two Integers
- 0036 - Valid Sudoku
- 0046 - Permutations
- 0049 - Group Anagrams
- 0053 - Maximum Subarray
- 0074 - Search a 2D Matrix
- 0077 - Combinations
- 0088 - Merge Sorted Array
- 0118 - Pascal's Triangle
- 0121 - Best Time to Buy and Sell Stock
- 0217 - Contains Duplicate
- 0238 - Product of Array Except Self
- 0242 - Valid Anagram
- 0347 - Top K Frequent Elements
- 0350 - Intersection of Two Arrays II
- 0383 - Ransom Note
- 0485 - Max Consecutive Ones
- 0566 - Reshape the Matrix
- 2235 - Add Two Integers