LeetCode C++ Solutions Repository

A collection of LeetCode algorithm problem solutions implemented in modern C++. This repository serves as a learning platform to help me become a master of C++ and DSA through systematic problem-solving.

🎯 Purpose

This repository is designed for:

• Learning and mastering DSA concepts through practical problem-solving
• Improving C++ programming skills using modern features when beneficial
• Building comprehensive knowledge of algorithms and data structures
• Systematic learning to become a C++ and DSA master

🚀 Modern C++ Features

This repository uses modern C++ features to write clean, efficient, and maintainable solutions:

• Modern algorithms - Range-based algorithms and efficient data processing
• Smart containers - Appropriate data structures for each problem
• Error handling - Robust and safe code practices
• Advanced concepts - Templates, concepts, and compile-time features
• Performance optimization - Move semantics, perfect forwarding, and efficient code

📚 Problems Solved

🎯 Array & Hashing

Key Patterns:

• Hash Map/Set: Two Sum, Contains Duplicate, Valid Anagram, Group Anagrams
• Array Manipulation: Product of Array Except Self, Longest Consecutive Sequence
• String Processing: Valid Anagram, Group Anagrams, Encode and Decode Strings
• Matrix/2D Arrays: Valid Sudoku
• Frequency Counting: Top K Frequent Elements, Valid Anagram, Group Anagrams

Problems:

• 1. Two Sum - Easy
• 36. Valid Sudoku - Medium
• 49. Group Anagrams - Medium
• 128. Longest Consecutive Sequence - Medium
• 217. Contains Duplicate - Easy
• 238. Product of Array Except Self - Medium
• 242. Valid Anagram - Easy
• 271. Encode and Decode Strings - Medium
• 347. Top K Frequent Elements - Medium

🎯 Two Pointers

Key Patterns:

• Opposite Direction: Valid Palindrome, Container With Most Water
• Same Direction: Two Sum II - Input Array Is Sorted, 3Sum
• Prefix/Suffix Arrays: Trapping Rain Water
• Greedy + Two Pointers: Container With Most Water
• Sorting + Two Pointers: 3Sum

Problems:

• 11. Container With Most Water - Medium
• 15. 3Sum - Medium
• 42. Trapping Rain Water - Hard
• 125. Valid Palindrome - Easy
• 167. Two Sum II - Input Array Is Sorted - Easy

🛠️ Development Setup

Simple Compilation

For basic testing, you can compile individual solutions:

# Navigate to problem directory
cd "src/1. Two Sum"

# Compile with C++23
g++ -std=c++23 -O2 main.cpp -o solution
# or
clang++ -std=c++23 -O2 main.cpp -o solution

# Run
./solution

Compiler Requirements

• GCC: Version 13+ with -std=c++23
• Clang: Version 17+ with -std=c++23
• MSVC: Version 19.35+ with /std:c++23

📝 Contributing

1. Fork the repository
2. Create a new branch for your solution
3. Add your solution in the appropriate problem directory
4. Follow the existing naming convention: Problem Number. Problem Name/
5. Submit a pull request

Solution Guidelines

• Use C++23 standard - Leverage modern features when beneficial
• Write clear, readable code with proper comments
• Include problem description in comments
• Follow C++23 best practices - RAII, smart pointers, constexpr
• Test solutions with multiple test cases
• Include time and space complexity analysis
• Document C++23 features used in your solution

🧠 Learning Approach

Comprehensive Documentation System

• Problem-Specific Learning: Each problem includes detailed README with multiple approaches
• C++ Mastery: Extensive C++ documentation covering fundamentals to advanced topics
• DSA Foundation: Complete data structures and algorithms reference
• Pattern Recognition: Common algorithmic patterns and when to use them
• Progressive Learning: Structured roadmap from basics to advanced concepts

Knowledge Building Strategy

• Theory + Practice: Combine conceptual understanding with hands-on coding
• Multiple Solutions: Learn different approaches to the same problem
• Modern C++: Use latest C++23 features for efficient and clean code
• Systematic Progress: Track learning through comprehensive documentation
• Mastery Focus: Deep understanding over quick solutions

📊 Progress Tracking

Quick Stats

• Total Problems: 14
• Categories: Array & Hashing, Two Pointers
• Easy: 5 | Medium: 8 | Hard: 1

C++23 Features Used

• STL Containers: std::unordered_map, std::unordered_set, std::priority_queue, std::vector, std::string
• STL Algorithms: std::sort, std::transform, std::accumulate, std::ranges, std::is_sorted, std::max_element
• Modern C++: std::ranges, std::views, std::format, auto keyword, structured bindings, constexpr
• Two Pointers: Efficient array traversal, sliding window techniques, greedy algorithms

📖 Learning Resources

Repository Documentation

• Learning Roadmap - Comprehensive learning path for C++ and DSA mastery
• C++ Documentation - Complete C++ programming concepts and modern features
• DSA Documentation - Data structures and algorithms fundamentals to advanced topics
• Algorithm Patterns - Common algorithmic patterns and techniques
• Problem Categories - Problems organized by topic and difficulty

External Resources

• LeetCode Official Website
• Neetcode 150 Roadmap
• C++23 Reference
• C++23 Standard
• std::ranges Documentation
• std::views Documentation
• Algorithm Visualization
• C++ Core Guidelines
• Modern C++ Features

📄 License

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

🤝 Acknowledgments

• ISO C++ Committee for C++23 standard
• LeetCode for providing excellent algorithmic problems
• The C++ community for continuous improvements to the language
• All contributors who help improve this repository

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Happy Learning! 🚀✨

This repository is designed for comprehensive learning and mastery building, focusing on DSA concepts and modern C++ programming.