🚀 DSA & LeetCode Solutions

A comprehensive collection of Data Structures & Algorithms solutions from LeetCode, HackerRank, and SQL challenges.

Master problem-solving skills and ace technical interviews with multi-language implementations!

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📚 Table of Contents

• About
• Repository Structure
• Languages Supported
• Problem Categories
• Getting Started
• How to Navigate
• Contributing
• Resources
• Connect

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🎯 About

This repository is a comprehensive archive of solutions to competitive programming problems, featuring:

• ✅ Multiple Language Support: C++, Python3, C, C#, SQL, and JavaScript
• ✅ Well-Organized: Categorized by data structures and algorithms
• ✅ Interview Preparation: Perfect for coding interviews and technical assessments
• ✅ SQL Mastery: Complete SQL 50 problem set with detailed solutions
• ✅ Active Development: Regularly updated with new solutions

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📂 Repository Structure

DSA---LeetCode/
│
├── 📁 30 Days of JavaScript/      # JavaScript Challenge Solutions
│
├── 📁 Array/                      # Array problems (C, C++, C#, Python3)
├── 📁 Linked List/                # Linked List implementations
├── 📁 Stack/                      # Stack problems
├── 📁 Queue/                      # Queue problems
├── 📁 Binary Tree/                # Binary Tree solutions
├── 📁 Binary Search Tree/         # BST problems
├── 📁 Binary Search/              # Binary Search algorithms
│
├── 📁 Hash Table/                 # Hash Table/Map problems
├── 📁 Heap(Priority Queue)/       # Heap data structure
├── 📁 Graphs/                     # Graph algorithms
├── 📁 Trees/                      # General tree problems
│
├── 📁 Dynamic Programming/        # DP solutions (C, C++, Python3)
├── 📁 Greedy/                     # Greedy algorithms
├── 📁 Divide and Conquer/         # D&C techniques
├── 📁 BackTracking/               # Backtracking problems
├── 📁 Recursion/                  # Recursive solutions
├── 📁 Memoization/                # Memoization techniques
│
├── 📁 Breadth-First-Search(BFS)/  # BFS algorithms
├── 📁 Depth-First-Search(DFS)/    # DFS algorithms
│
├── 📁 Two Pointers/               # Two pointer technique
├── 📁 Sliding Window/             # Sliding window problems
├── 📁 Prefix Sum/                 # Prefix sum technique
├── 📁 Sorting/                    # Sorting algorithms
├── 📁 Counting/                   # Counting techniques
├── 📁 Bit Manipulation/           # Bitwise operations
│
├── 📁 Maths -- Geometry/          # Mathematical problems
├── 📁 Matrix/                     # 2D array problems
├── 📁 Strings/                    # String manipulation
│
├── 📁 SQL 50/                     # Complete SQL 50 challenge
├── 📁 Database/                   # Additional SQL problems
│
├── 📁 HackerRank/                 # HackerRank solutions (C++)
│
└── 📄 README.md                   # You are here!

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💻 Languages Supported

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🔥 Problem Categories

📊 Data Structures

• Linear: Array, Linked List, Stack, Queue
• Hierarchical: Binary Tree, Binary Search Tree, Trees
• Hash-based: Hash Table, Hash Map
• Advanced: Heap (Priority Queue), Matrix

🧮 Algorithms

• Search: Binary Search, BFS, DFS
• Optimization: Dynamic Programming, Greedy, Divide and Conquer
• Traversal: Backtracking, Recursion
• Techniques: Two Pointers, Sliding Window, Prefix Sum
• Fundamentals: Sorting, Counting, Bit Manipulation
• Graph: Graph traversal and algorithms

🗄️ Database

• SQL 50: Complete problem set with solutions
• Advanced Queries: Joins, Aggregations, Subqueries
• Database Design: Schema optimization and query performance

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🚀 Getting Started

Prerequisites

• C++: GCC/G++ compiler or Visual Studio
• Python: Python 3.x
• SQL: MySQL, PostgreSQL, or any SQL database
• JavaScript: Node.js (for 30 Days of JavaScript)

Installation

# Clone the repository
git clone https://github.com/Muhammad-Taqi-Dev/DSA---LeetCode.git

# Navigate to the directory
cd DSA---LeetCode

# Browse solutions by category
cd "Array/C++"

Running Solutions

C++ Example:

g++ -o solution problem_name.cpp
./solution

Python Example:

python3 problem_name.py

SQL Example:

-- Execute in your SQL client
SOURCE problem_name.sql;

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🧭 How to Navigate

1. By Topic: Navigate to the specific algorithm or data structure folder
2. By Language: Each category contains subfolders for different languages
3. By Platform: Check HackerRank/ for HackerRank-specific solutions
4. SQL Practice: Head to SQL 50/ for comprehensive SQL problems

Example Path:

Array/ → C++/ → [specific_problem.cpp]
Dynamic Programming/ → Python3/ → [specific_problem.py]
SQL 50/ → [specific_query.sql]

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🤝 Contributing

Contributions are highly encouraged! Whether it's:

• 🐛 Bug fixes
• ✨ New solutions
• 📝 Documentation improvements
• 🌐 Solutions in new languages

How to Contribute:

1. Fork the repository
2. Create a new branch

   git checkout -b feature/new-solution

3. Add your solution in the appropriate directory
4. Follow the naming convention: ProblemName.extension
5. Commit your changes

   git commit -m "Add: [Problem Name] in [Language]"

6. Push to your fork

   git push origin feature/new-solution

7. Create a Pull Request

Contribution Guidelines:

• Include problem number/name in comments
• Add time and space complexity analysis
• Write clean, readable code
• Test your solution before submitting

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📖 Resources

Learning Platforms

• LeetCode - Practice coding problems
• HackerRank - Coding challenges
• GeeksforGeeks - DSA tutorials

Useful Links

• Big-O Cheat Sheet
• Visualgo - Algorithm visualizations
• CP-Algorithms - Competitive programming algorithms

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🌟 Connect

Found this helpful? Give it a ⭐!

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📈 Keep Learning, Keep Growing!

"The only way to learn a new programming language is by writing programs in it." - Dennis Ritchie

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Last Updated: February 2026