Leetcode Problems Solutions

"The only way to do great work is to love what you do." -Steve Jobs

This repository contains my solutions to various Leetcode problems. Below is a table listing all the problems, along with their tags, difficulty level, and a checkbox for you to mark if you've solved the problem.

Feel free to fork this repository and contribute by adding more problems or improving the existing solutions.

Problems List

ID	Title	Tags	Difficulty	Solved	Solution File
1	Two Sum	Array, Hash Table	Easy	✔️	Two Sum.java
2	Add Two Numbers	Linked List, Math	Medium	✔️	Add 2 Number.java
3	Longest Substring Without Repeating Characters	Hash Table, String, Sliding Window	Medium	✔️	Longest Substring Without Repeatition.java
4	Median of Two Sorted Arrays	Array, Binary Search	Hard	✔️	Median Of 2 Sorted Array.java
5	Longest Palindromic Substring	String, Dynamic Programming	Medium	❌
6	ZigZag Conversion	String	Medium	❌
7	Reverse Integer	Math	Easy	✔️	Reverse Integer.java
8	String to Integer (atoi)	String	Medium	✔️	String To Integer.java
9	Palindrome Number	Math	Easy	✔️	Pallindrome Number.java
10	Regular Expression Matching	String, Dynamic Programming	Hard	❌
11	Container With Most Water	Array, Two Pointers	Medium	❌
12	Integer to Roman	Math	Medium	✔️	Integer To Roman.java
13	Roman to Integer	Math	Easy	✔️	Roman To Integer.java
14	Longest Common Prefix	String	Easy	✔️	Longest Common Prefix.java
15	3Sum	Array, Two Pointers	Medium	❌	Letter Combination Of Phone Number.java
16	3Sum Closest	Array, Two Pointers	Medium	❌
17	Letter Combinations of a Phone Number	Backtracking, String	Medium	✔️	Letter Combination Of Phone Numbers.java
18	4Sum	Array, Two Pointers	Medium	❌
19	Remove Nth Node From End of List	Linked List	Medium	✔️	Remove Nth Node From End.java
20	Valid Parentheses	Stack, String	Easy	✔️	Valid Paranthesis.java
21	Merge Two Sorted Lists	Linked List	Easy	✔️	Merge Two Sorted Lists.java
22	Generate Parentheses	Backtracking	Medium	✔️	Generate Parantheses.java
23	Merge k Sorted Lists	Linked List, Divide and Conquer	Hard	✔️	Merge K Sorted Lists.java
24	Swap Nodes in Pairs	Linked List	Medium	❌	Solution24.java
25	Reverse Nodes in k-Group	Linked List	Hard	✔️	Reverse Nodes In K Groups.java
26	Remove Duplicates from Sorted Array	Array	Easy	✔️	Remove Duplicates From Sorted Array.java
27	Remove Element	Array	Easy	✔️	Remove Element.java
28	Find the Index Of First Occurence In A String	String	Easy	✔️	Index Of First Occurence In A String.java
29	Divide Two Integers	Math	Medium	❌	Solution29.java
30	Substring with Concatenation of All Words	Hash Table, String, Sliding Window	Hard	❌	Solution30.java
31	Next Permutation	Array, Two Pointers	Medium	❌	Solution31.java
32	Longest Valid Parentheses	String, Stack	Hard	✔️	Longest Valid Parantheses.java
33	Search in Rotated Sorted Array	Array, Binary Search	Medium	✔️	Search In Rotated Sorted Array.java
34	Find First and Last Position of Element in Sorted Array	Array, Binary Search	Medium	✔️	First And Last Position Of Element In Sorted Array.java
35	Search Insert Position	Array, Binary Search	Easy	✔️	Search Insert Position.java
36	Valid Sudoku	Array, Hash Table	Medium	❌	Solution36.java
37	Sudoku Solver	Backtracking	Hard	❌	Solution37.java
38	Count and Say	String	Easy	❌	Solution38.java
39	Combination Sum	Backtracking	Medium	❌	Solution39.java
40	Combination Sum II	Backtracking	Medium	❌	Solution40.java
41	First Missing Positive	Array	Hard	✔️	First Missing Positive.java
42	Trapping Rain Water	Array, Two Pointers	Hard	✔️	Trapping Rain Water.java
43	Multiply Strings	Math, String	Medium	❌	Solution43.java
44	Wildcard Matching	String, Dynamic Programming	Hard	❌	Solution44.java
45	Jump Game II	Array, Greedy	Hard	❌	Solution45.java
46	Permutations	Backtracking	Medium	❌	Solution46.java
47	Permutations II	Backtracking	Medium	❌	Solution47.java
48	Rotate Image	Array	Medium	❌	Solution48.java
49	Group Anagrams	Hash Table, String	Medium	✔️	Group Anagrams.java
50	Pow(x, n)	Math	Medium	❌	Solution50.java
51	N-Queens	Backtracking	Hard	❌	Solution51.java
52	N-Queens II	Backtracking	Hard	❌	Solution52.java
53	Maximum Subarray	Array, Dynamic Programming	Easy	❌	Solution53.java
54	Spiral Matrix	Array	Medium	❌	Spiral Matrix.java
55	Jump Game	Array, Greedy	Medium	❌	Solution55.java
56	Merge Intervals	Array, Sorting	Medium	❌	Solution56.java
57	Insert Interval	Array	Hard	❌	Solution57.java
58	Length of Last Word	String	Easy	✔️	Length Of Last Word.java
59	Spiral Matrix II	Array	Medium	❌	Spiral MatrixII.java
60	Permutation Sequence	Math, Backtracking	Hard	❌	Solution60.java
61	Rotate List	Linked List	Medium	✔️	Rotate List.java
62	Unique Paths	Dynamic Programming	Medium	❌	Solution62.java
63	Unique Paths II	Dynamic Programming	Medium	❌	Solution63.java
64	Minimum Path Sum	Dynamic Programming	Medium	❌	Solution64.java
65	Valid Number	String	Hard	❌	Solution65.java
66	Plus One	Array	Easy	✔️	Plus One.java
67	Add Binary	String, Math	Easy	✔️	Add Binary.java
68	Text Justification	String	Hard	❌	Solution68.java
69	Sqrt(x)	Binary Search, Math	Easy	✔️	Sqrt Of X.java
70	Climbing Stairs	Dynamic Programming	Easy	✔️	Climbing Stairs.java
71	Simplify Path	Stack, String	Medium	❌	Solution71.java
72	Edit Distance	String, Dynamic Programming	Hard	✔️	Edit Distance.java
73	Set Matrix Zeroes	Array	Medium	❌	Solution73.java
74	Search a 2D Matrix	Array, Binary Search	Medium	❌	Solution74.java
75	Sort Colors	Array, Two Pointers	Medium	✔️	Sort Colors.java
76	Minimum Window Substring	Hash Table, String, Sliding Window	Hard	❌	Solution76.java
77	Combinations	Backtracking	Medium	❌	Solution77.java
78	Subsets	Backtracking	Medium	❌	Solution78.java
79	Word Search	Backtracking	Medium	✔️	Word Search.java
80	Remove Duplicates from Sorted Array II	Array	Medium	❌	Solution80.java
81	Search in Rotated Sorted Array II	Array	Medium	❌	Solution81.java
82	Remove Duplicates from Sorted List II	Linked List	Medium	❌	Remove Duplicates From Sorted List.java
83	Remove Duplicates from Sorted List	Linked List	Easy	✔️	Solution83.java
84	Largest Rectangle in Histogram	Array, Stack	Hard	❌	Solution84.java
85	Maximal Rectangle	Array, Stack	Hard	❌	Solution85.java
86	Partition List	Linked List	Medium	❌	Solution86.java
87	Scramble String	String, Dynamic Programming	Hard	❌	Solution87.java
88	Merge Sorted Array	Array	Easy	✔️	Merge Sorted List.java
89	Gray Code	Bit Manipulation	Medium	❌	Solution89.java
90	Subsets II	Backtracking	Medium	❌	Solution90.java
91	Decode Ways	Dynamic Programming	Medium	❌	Solution91.java
92	Reverse Linked List II	Linked List	Medium	❌	Solution92.java
93	Restore IP Addresses	Backtracking	Medium	❌	Solution93.java
94	Binary Tree Inorder Traversal	Tree, Stack	Easy	✔️	Binary Tree InOrder Traversal.java
95	Unique Binary Search Trees II	Tree, Dynamic Programming	Medium	❌	Solution95.java
96	Unique Binary Search Trees	Tree, Dynamic Programming	Medium	❌	Solution96.java
97	Interleaving String	String, Dynamic Programming	Hard	❌	Solution97.java
98	Validate Binary Search Tree	Tree, Depth First Search	Medium	❌	Solution98.java
99	Recover Binary Search Tree	Tree, Depth First Search	Hard	❌	Solution99.java
100	Same Tree	Tree, Depth First Search, Breadth First Search	Hard	✔️	Solution100.java

| ... | ... | ... | ... | [ ] |

Usage

1. Clone the repository:

   git clone https://github.com/yourusername/leetcode-solutions.git

2. Navigate to the directory:

   cd leetcode-solutions

3. Create a new branch:

   git checkout -b new-branch

4. Add your solutions:
5. Commit your changes:

   git commit -am "Added solutions to problem 1 and problem 2"

6. Push to the branch:

   git push origin new-branch

7. Submit a pull request
8. Star the repository
9. Relax and wait for your PR to be merged
10. Celebrate - you've done your part! 🎉