explain Pythagoras Triplet

[ezabhishek1]

add explains for Pythagorean Triplet a medium level problem

[rasenshuriken12]

Fix for #4 Explain Pythagorean Triplet

Description

This PR adds the solution and explanation for the "Pythagorean Triplet" problem.

Changes include:

• 📝 explain.md with comprehensive explanation
• 📊 Detailed dry run and complexity analysis
• 🧪 Edge cases covered

Type of Change

• New feature (adding new solution)
• Documentation (adding explanation)

Checklist

• Code follows style guidelines
• Explanation is clear and comprehensive
• Added test cases
• Complexity analysis included