Welcome to my DSA repository! This repository contains a comprehensive collection of data structures and algorithm problems, solutions, and notes. It's meant for practice, learning, and interview preparation.

DSA/
├── LeetCode/                    # Organized LeetCode solutions by difficulty
│   ├── Easy/                   # Easy difficulty problems
│   ├── Medium/                 # Medium difficulty problems
│   ├── Hard/                   # Hard difficulty problems
│   └── README.md               # LeetCode section documentation
├── scripts/                     # Automation scripts
│   ├── add-leetcode-solution.sh # Script to add new LeetCode solutions
│   └── templates/              # Solution and README templates
│       ├── solution-template.py
│       ├── solution-template.java
│       ├── solution-template.cpp
│       ├── solution-template.js
│       └── problem-readme-template.md
├── .github/
│   └── workflows/
│       └── leetcode-sync.yml   # GitHub Actions workflow
└── README.md                    # This file

The easiest way to add a new LeetCode solution is using the provided script:

# Navigate to repository root
cd /path/to/DSA

# Add a new solution
./scripts/add-leetcode-solution.sh -n <number> -t "<title>" -d <difficulty> -l <language>

Example:

# Add "Two Sum" in Python
./scripts/add-leetcode-solution.sh -n 1 -t "Two Sum" -d Easy -l python -g "Array,Hash Table"

# Add and auto-commit
./scripts/add-leetcode-solution.sh -n 15 -t "3Sum" -d Medium -l java -g "Array,Two Pointers" -c

# Add, commit, and push
./scripts/add-leetcode-solution.sh -n 4 -t "Median of Two Sorted Arrays" -d Hard -l cpp -p

• Python (.py) - Default
• Java (.java)
• C++ (.cpp)
• JavaScript (.js)

Run the GitHub Actions workflow or use find LeetCode/{Easy,Medium,Hard} -mindepth 1 -maxdepth 1 -type d | wc -l to update counts.

• Go to LeetCode
• Solve the problem
• Test with multiple test cases

./scripts/add-leetcode-solution.sh \
  -n <problem_number> \
  -t "<Problem Title>" \
  -d <Easy|Medium|Hard> \
  -l <language> \
  -g "Tag1,Tag2"

The script creates:

• LeetCode/{Difficulty}/{number}-{slug}/solution.{ext}
• LeetCode/{Difficulty}/{number}-{slug}/README.md

Edit these files with your solution and documentation.

Fill in the README.md with:

• Problem description (copy from LeetCode)
• Your approach and algorithm
• Complexity analysis
• Test cases
• Notes and related problems

git add LeetCode/
git commit -m "Add LeetCode #<number>: <Title> (<Difficulty>)"
git push

Or use the -p flag with the script to do this automatically!

Each solution includes:

• Header with problem metadata
• Time and space complexity placeholders
• Approach description section
• Well-structured solution method
• Test cases section

• Problem description
• Approach explanation
• Step-by-step algorithm
• Complexity analysis with explanations
• Multiple solution approaches
• Test cases with expected outputs
• Notes and tips
• Related problems

The repository includes a GitHub Actions workflow that:

1. Validates Structure - Ensures all problems have required files
2. Counts Problems - Tracks problems by difficulty
3. Generates Lists - Creates organized problem lists
4. Updates Statistics - Keeps README stats current (optional)

Workflow runs on:

• Push to main branch (when LeetCode files change)
• Manual trigger via GitHub Actions UI
• Scheduled daily updates (optional, can be enabled)

1. ✅ Solve the problem on LeetCode
2. ✅ Understand time and space complexity
3. ✅ Test with edge cases
4. ✅ Consider alternative approaches

1. 📝 Use meaningful variable names
2. 💬 Add comments for complex logic
3. 🎨 Follow language-specific conventions
4. 🧪 Include comprehensive test cases

1. 📖 Explain your thought process
2. 🔍 Document alternative approaches
3. 📊 Analyze time and space complexity
4. ⚠️ Note edge cases and constraints

Organized by difficulty in the LeetCode/ directory:

• Easy/ - Foundational problems, basic algorithms
• Medium/ - Common interview problems, intermediate concepts
• Hard/ - Advanced algorithms, complex data structures

Each problem follows the structure:

{number}-{slug}/
├── solution.{ext}   # Your solution code
└── README.md        # Problem documentation

The scripts/ directory contains:

• add-leetcode-solution.sh - Main automation script
• templates/ - Code and documentation templates

• Arrays & Strings: Manipulation, searching, sorting
• Linked Lists: Traversal, reversal, cycle detection
• Trees & Graphs: Traversal (DFS/BFS), searching
• Dynamic Programming: Memoization, tabulation
• Greedy Algorithms: Optimization problems
• Backtracking: Permutations, combinations
• Binary Search: Searching, optimization
• Two Pointers: Array problems, string problems
• Sliding Window: Subarray problems
• Hash Tables: Fast lookups, counting

• LeetCode - Practice platform
• NeetCode - Curated problem lists
• LeetCode Patterns - Common patterns

• Blind 75 - Essential interview questions
• Grind 75 - Structured study plan

This is a personal learning repository, but contributions and suggestions are welcome!

To contribute:

1. Fork the repository
2. Create a feature branch
3. Add your solution using the provided scripts
4. Submit a pull request

This repository is for educational purposes. All LeetCode problems are property of LeetCode LLC.

This repository is maintained by @vikashkumar016 as part of continuous learning and interview preparation.

Happy Coding! 🚀

For questions or suggestions, please open an issue or reach out via GitHub.

Last Updated: January 2026