LeetCode Solutions 🚀

A comprehensive collection of LeetCode problem solutions implemented in Python, organized by topics and difficulty levels.

📁 Repository Structure

This repository contains solutions to various LeetCode problems covering multiple data structures and algorithms topics:

🌐 Graph Problems

• Graph Day 1 - Connected Components (DFS, BFS, Union-Find)
• Graph Day 2 - BFS Solutions (Same Tree, Invert Tree, Symmetric Tree)
• Graph Day 3 - DFS Solutions (Same Tree, Invert Tree, Symmetric Tree)
• Graph Day 4 - Number of Provinces (DFS & BFS)

🔗 Linked List Problems

• 21. Merge Two Sorted Lists
• 141. Linked List Cycle

🏃‍♂️ Dynamic Programming

• 70. Climbing Stairs - Multiple approaches (Recursion, Memoization, Tabulation)
• 509. Fibonacci Number - DP solutions
• 416. Partition Equal Subset Sum
• 368. Largest Divisible Subset

🔢 Array Problems

• 1. Two Sum - Brute Force & HashMap approaches
• 53. Maximum Subarray - Kadane's Algorithm
• 73. Set Matrix Zeroes
• 88. Merge Sorted Array
• 135. Candy
• 918. Maximum Sum Circular Subarray
• 1191. K-Concatenation Maximum Sum
• 1331. Rank Transform of an Array
• 1979. Find Greatest Common Divisor of Array

🧮 Mathematical Problems

• 1922. Count Good Numbers
• 2929. Distribute Candies Among Children II

🎯 Greedy Algorithms

• 2895. Minimum Processing Time

🎲 Game Theory & Simulation

• 909. Snakes and Ladders - BFS approach
• 1298. Maximum Candies You Can Get from Boxes

🔍 Search & Optimization

• 2503. Maximum Number of Points From Grid Queries - Dijkstra's Algorithm
• 2780. Minimum Index of a Valid Split - Array manipulation
• 3169. Count Days Without Meetings - Interval merging
• 3375. Minimum Operations to Make Array Values Equal to K

🌳 Tree Problems

• 1123. Lowest Common Ancestor of Deepest Leaves

📊 Advanced Problems

• 2685. Count the Number of Complete Components
• 2874. Maximum Value of an Ordered Triplet II

🏷️ Problem Categories

By Difficulty

• Easy: Two Sum, Climbing Stairs, Fibonacci, Merge Sorted Array, etc.
• Medium: Maximum Subarray, Set Matrix Zeroes, Graph problems, etc.
• Hard: Advanced DP and Graph problems

By Algorithm Type

• Dynamic Programming: Climbing Stairs, Fibonacci, Partition Sum, etc.
• Graph Algorithms: DFS, BFS, Union-Find, Connected Components
• Array Manipulation: Two Sum, Maximum Subarray, Set Matrix Zeroes
• Greedy Algorithms: Candy Distribution, Processing Time
• Mathematical: GCD, Modular Arithmetic, Combinatorics

🚀 Key Features

• Multiple Approaches: Many problems include multiple solution approaches (Brute Force, Optimized, Different Algorithms)
• Detailed Comments: Each solution includes problem description and explanation
• Time/Space Complexity: Analysis provided for optimal solutions
• Clean Code: Well-structured and readable Python implementations

📈 Progress Tracking

This repository contains solutions to 25+ LeetCode problems covering:

• Graph Theory and Traversals
• Dynamic Programming Patterns
• Array and String Manipulation
• Mathematical Algorithms
• Tree and Binary Tree Problems
• Greedy Algorithms
• Game Theory and Simulation

🛠️ How to Use

1. Clone the repository
2. Navigate to specific problem files
3. Each file contains:
   • Problem statement
   • Example test cases
   • Solution implementation(s)
   • Time and space complexity analysis

📚 Study Guide

For Beginners

Start with: Two Sum → Climbing Stairs → Maximum Subarray → Merge Two Sorted Lists

For Graph Problems

Follow the Graph Day series (1-4) for comprehensive coverage of graph algorithms

For Dynamic Programming

Begin with: Fibonacci → Climbing Stairs → Partition Equal Subset Sum

🤝 Contributing

Feel free to contribute by:

• Adding new solutions
• Improving existing solutions
• Adding alternative approaches
• Enhancing documentation

📄 License

This project is open source and available under the MIT License.

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Happy Coding! 🎯

Keep practicing and improving your problem-solving skills!