Zig Coding Interview Challenges

A comprehensive collection of coding interview problems implemented in Zig, covering essential algorithms and data structures commonly encountered in technical interviews.

🎯 Overview

This repository contains 18 coding challenges organized by problem category, each implemented with clean, well-documented Zig code. The solutions demonstrate various algorithmic approaches, optimization techniques, and Zig-specific features like comptime evaluation.

📁 Project Structure

Each challenge is organized in its own directory with the following structure:

challenge-name/
├── src/
│   └── main.zig          # Main implementation
├── build.zig             # Build configuration
└── build.zig.zon         # Package configuration

🧮 Challenge Categories

Arrays & Two Pointers

• 2 - Container Most Water - Two-pointer technique for maximum area calculation
• 3 - Valid Mountain Array - Array validation with specific patterns
• 4 - Boats to Save People - Greedy algorithm with two pointers
• 5 - Move Zeros - In-place array manipulation
• 6 - Longest Substring - Sliding window technique
• 7 - First and Last Position - Binary search implementation
• 8 - First Bad Version - Binary search optimization

Mathematics & Bit Manipulation

• 9 - Missing Number (Gauss Formula) - Mathematical approach using sum formula
• 10 - Sieve of Eratosthenes - Prime number generation with comptime
• 11 - XOR Single Numbers - Bitwise operations for finding unique elements
• 12 - Robot Return to Origin - Coordinate tracking and validation
• 13 - Binary Sum - Binary arithmetic operations

Hash Tables & Hash Maps

• 14 - Two Sum - Classic hash map problem with O(n) solution
• 15 - Contains Duplicates - Duplicate detection using hash sets
• 17 - 4Sum II - Advanced hash map usage for multi-array problems
• 18 - Minimum Window Substring (Hard) - Complex sliding window with hash maps

Advanced Algorithms

• 16 - Boyer-Moore Majority Element - Voting algorithm implementation

🚀 Getting Started

Prerequisites

• Zig (version 0.11.0 or later)

Running a Challenge

Navigate to any challenge directory and run:

# Build and run
zig build run

# Run tests
zig build test

# Build only
zig build

Example Usage

cd "14 - Hash: two sum"
zig build run

Expected output:

Positions 1 and 2

🔧 Key Zig Features Demonstrated

• Memory Management: Arena allocators, manual memory management
• Comptime Evaluation: Compile-time computations for performance
• Error Handling: Zig's explicit error handling with try and !
• Type System: Strong typing with type inference
• Performance: Zero-cost abstractions and manual optimizations
• Hash Maps: std.hash_map.AutoHashMap usage patterns
• Slices vs Arrays: Different approaches to data handling

📊 Complexity Analysis

Each solution includes:

• Time Complexity: Big O notation for runtime performance
• Space Complexity: Memory usage analysis
• Alternative Approaches: Multiple solution strategies where applicable

🎓 Learning Objectives

This collection helps you master:

1. Algorithm Design Patterns

   • Two pointers technique
   • Sliding window
   • Binary search
   • Hash table optimization

2. Zig Programming Concepts

   • Memory allocators
   • Comptime evaluation
   • Error handling
   • Performance optimization

3. Interview Preparation

   • Common problem patterns
   • Optimization techniques
   • Code organization
   • Testing strategies

🤝 Contributing

Feel free to:

• Add new challenges
• Improve existing solutions
• Add alternative implementations
• Enhance documentation
• Report issues or bugs

📝 License

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

🔗 Resources

• Zig Language Reference
• Zig Standard Library
• LeetCode - Source of many challenge problems
• Zig Learning Resources

---

Happy Coding! 🎉

Each challenge is self-contained and can be studied independently. Start with the category that interests you most or follow the numerical order for a structured learning path.