30-Day-LeetCoding-Challenge

Solutions to every question in the 30 Day LeetCoding challenge

Introduction

Hi guys!
Lockdown gave me ample time to get started with solving some question on Leetcode. I have started with the 30 day Leetcode challenge.
As an exercise, I am also uploading the solutions to these questions (best to my knowledge). Go ahead, take a look!

Week 1

• Single Number
  Leetcode URL
  Solution

• Happy Number
  Leetcode URL
  Solution

• Maximum Subarray
  Leetcode URL
  Solution

• Move Zeroes
  Leetcode URL
  Solution

• Best Time to Buy and Sell Stock II
  Leetcode URL
  Solution

• Group Anagrams
  Leetcode URL
  Solution

• Counting Elements
  Leetcode URL
  Solution

Week 2

• Middle of the Linked List
  Leetcode URL
  Solution

• Backspace String Compare
  Leetcode URL
  Solution

• Min Stack
  Leetcode URL
  Solution | 1 vector approach
  Solution | 2 stack approach

• Diameter of Binary Tree
  Leetcode URL
  Solution

• Last Stone Weight
  Leetcode URL
  Solution

• Contiguous Array
  Leetcode URL
  Solution

• Perform String Shifts
  Leetcode URL
  Solution

Week 3

• Product of Array Except Self
  Leetcode URL
  Solution

• Valid Parenthesis String
  Leetcode URL
  Solution

• Number of Islands
  Leetcode URL
  Solution

• Minimum Path Sum
  Leetcode URL
  Solution

• Search in Rotated Sorted Array
  Leetcode URL
  Solution

• Construct Binary Search Tree from Preorder Traversal
  Leetcode URL
  Solution

• Leftmost Column with at Least a One
  Leetcode URL
  Solution

Week 4

• Subarray Sum Equals K
  Leetcode URL
  Solution

• Bitwise AND of Numbers Range
  Leetcode URL
  Solution

• LRU Cache
  Leetcode URL
  Solution

• Jump Game
  Leetcode URL
  Solution

• Longest Common Subsequence
  Leetcode URL
  Solution | Bottom Up approach
  Solution | Top Down approach

• Maximal Square
  Leetcode URL
  Solution

• First Unique Number
  Leetcode URL
  Solution | Doubly Linked List approach
  Solution | Queue approach

Week 5

• Binary Tree Maximum Path Sum
  Leetcode URL
  Solution

• Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree
  Leetcode URL
  Solution