Introduction:

Welcome to my Leetcode Grind75 repository! This collection houses my solutions to the popular Grind75 challenge, inspired by the Blind75 project by Yangshun Tay.

What is Grind75?

Grind75 is a curated list of 75 Leetcode problems designed to systematically improve your problem-solving skills and prepare you for technical interviews. It builds upon the success of Blind75, offering variations and additional exercises for a more comprehensive learning experience.

Where to Learn More:

• Grind75: https://www.techinterviewhandbook.org/grind75/
• Blind75: https://www.teamblind.com/post/New-Year-Gift---Curated-List-of-Top-75-LeetCode-Questions-to-Save-Your-Time-OaM1orEU
• Leetcode: https://leetcode.com/

Progress Tracking:

Here's a checklist to visualize your progress through the Grind75 challenges:

Key for Progress Markers:

• 🟢: Easy
• 🟠: Medium
• 🔴: Hard
• ⏳: In progress
• ❌: Not planning to attempt

Week 1	Problem	Easy	Medium	Hard	Status
1	Two Sum	🟢			Solved
2	Valid Parentheses	🟢			Solved
3	Merge Two Sorted Lists	🟢			Solved
4	Best Time to Buy and Sell Stock	🟢			Solved
5	Valid Palindrome	🟢			Solved
6	Invert Binary Tree	🟢			Solved
7	Valid Anagram	🟢			Solved
8	Binary Search	🟢			Solved
9	Flood Fill	🟢			Solved
10	Maximum Subarray		🟠		Solved
11	Lowest Common Ancestor of a Binary Search Tree	🟢			Solved
12	Insert Interval		🟠		Solved
13	01 Matrix		🟠
14	K Closest Points to Origin		🟠
15	Balanced Binary Tree	🟢			Solved

Week 2	Problem	Easy	Medium	Hard	Status
1	Linked List Cycle	🟢
2	Implement Queue using Stacks	🟢
3	First Bad Version	🟢
4	Ransom Note	🟢
5	Longest Substring Without Repeating Characters		🟠
6	3Sum		🟠
7	Binary Tree Level Order Traversal		🟠
8	Clone Graph		🟠
9	Evaluate Reverse Polish Notation		🟠
10	Course Schedule		🟠
11	Implement Trie (Prefix Tree)		🟠
12	Coin Change		🟠

Week 3	Problem	Easy	Medium	Hard	Status
1	Product of Array Except Self		🟠
2	Climbing Stairs	🟢
3	Longest Palindrome	🟢
4	Min Stack		🟠
5	Reverse Linked List	🟢
6	Validate Binary Search Tree		🟠
7	Number of Islands		🟠
8	Rotting Oranges		🟠
9	Search in Rotated Sorted Array		🟠
10	Combination Sum		🟠
11	Permutations		🟠
12	Merge Intervals		🟠

Week 4	Problem	Easy	Medium	Hard	Status
1	Lowest Common Ancestor of a Binary Tree		🟠
2	Time Based Key-Value Store		🟠
3	Minimum Window Substring			🔴
4	Serialize and Deserialize Binary Tree			🔴
5	Trapping Rain Water			🔴
6	Find Median from Data Stream			🔴
7	Majority Element	🟢
8	Add Binary	🟢
9	Diameter of Binary Tree	🟢
10	Middle of the Linked List	🟢

Week 5	Problem	Easy	Medium	Hard	Status
1	Accounts Merge		🟠
2	Sort Colors		🟠
3	Word Break		🟠
4	Partition Equal Subset Sum		🟠
5	String to Integer (atoi)		🟠
6	Spiral Matrix		🟠
7	Subsets		🟠
8	Binary Tree Right Side View		🟠
9	Longest Palindromic Substring		🟠
10	Word Ladder			🔴

Week 6	Problem	Easy	Medium	Hard	Status
1	Basic Calculator			🔴
2	Maximum Profit in Job Scheduling			🔴
3	Merge k Sorted Lists			🔴
4	Largest Rectangle in Histogram			🔴
5	Maximum Depth of Binary Tree	🟢
6	Contains Duplicate	🟢
7	Unique Paths		🟠
8	Construct Binary Tree from Preorder and Inorder Traversal		🟠
9	Container With Most Water		🟠
10	Letter Combinations of a Phone Number		🟠

Week 7	Problem	Easy	Medium	Hard	Status
1	Word Search		🟠
2	Find All Anagrams in a String		🟠
3	Minimum Height Trees		🟠
4	Task Scheduler		🟠
5	LRU Cache		🟠
6	Kth Smallest Element in a BST		🟠
7	Daily Temperatures		🟠
8	House Robber		🟠
9	Meeting Rooms	🟢
10	Roman to Integer	🟢
11	Backspace String Compare	🟢

Week 8	Problem	Easy	Medium	Hard	Status
1	Gas Station		🟠
2	Next Permutation		🟠
3	Valid Sudoku		🟠
4	Group Anagrams		🟠
5	Maximum Product Subarray		🟠
6	Design Add and Search Words Data Structure		🟠
7	Pacific Atlantic Water Flow		🟠
8	Remove Nth Node From End of List		🟠
9	Shortest Path to Get Food		🟠
10	Find the Duplicate Number		🟠

Week 9	Problem	Easy	Medium	Hard	Status
1	Top K Frequent Words		🟠
2	Binary Tree Maximum Path Sum			🔴
3	Maximum Frequency Stack			🔴
4	Counting Bits	🟢
5	Longest Increasing Subsequence		🟠
6	Graph Valid Tree		🟠
7	Course Schedule II		🟠
8	Swap Nodes in Pairs		🟠
9	Path Sum II		🟠
10	Longest Consecutive Sequence		🟠

Week 10	Problem	Easy	Medium	Hard	Status
1	Rotate Array		🟠
2	Odd Even Linked List		🟠
3	Decode String		🟠
4	Contiguous Array		🟠
5	Maximum Width of Binary Tree		🟠
6	Find K Closest Elements		🟠
7	Longest Repeating Character Replacement		🟠
8	Median of Two Sorted Arrays			🔴
9	Same Tree	🟢
10	Number of 1 Bits	🟢
11	Longest Common Prefix	🟢

Week 11	Problem	Easy	Medium	Hard	Status
1	Inorder Successor in BST		🟠
2	Jump Game		🟠
3	Add Two Numbers		🟠
4	Generate Parentheses		🟠
5	Sort List		🟠
6	Number of Connected Components in an Undirected Graph		🟠
7	Minimum Knight Moves		🟠
8	Subarray Sum Equals K		🟠
9	Asteroid Collision		🟠
10	Random Pick with Weight		🟠

Week 12	Problem	Easy	Medium	Hard	Status
1	Kth Largest Element in an Array		🟠
2	Longest Increasing Path in a Matrix			🔴
3	Longest Valid Parentheses			🔴
4	Design In-Memory File System			🔴
5	Employee Free Time			🔴
6	Single Number	🟢
7	Palindrome Linked List	🟢
8	Move Zeroes	🟢
9	Maximal Square		🟠
10	Rotate Image		🟠
11	Binary Tree Zigzag Level Order Traversal		🟠
12	Design Hit Counter		🟠
13	Path Sum III		🟠
14	Pow(x, n)		🟠
15	Search a 2D Matrix		🟠
16	Largest Number		🟠