feat: Add Pascal's Triangle implementation in Java

[rakshityadav1868]

Description

Added a comprehensive Pascal's Triangle implementation in Java as part of Hacktoberfest 2025.

Type of Change

• New feature (non-breaking change which adds functionality)
• Bug fix
• Documentation update

What was implemented?

• Created PascalsTriangle.java in the /java directory
• Implemented the core algorithm to generate Pascal's Triangle
• Added two printing methods:
  • printTriangleSimple() - Left-aligned simple output
  • printTriangle() - Beautiful centered formatted output
• Includes comprehensive JavaDoc documentation
• Input validation for edge cases

Algorithm Details

• Time Complexity: O(n²) where n is the number of rows
• Space Complexity: O(n²) for storing the triangle
• Each number in the triangle is the sum of the two numbers directly above it

Features

✅ Interactive user input via Scanner
✅ Formatted and simple output options
✅ Proper documentation and comments
✅ Input validation (handles edge cases)
✅ Follows repository coding standards

Testing

The implementation includes a main method that can be run directly to test the functionality.

Example Output

For n=5:
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1

Related Issue

Resolves the first Hacktoberfest issue for Pascal's Triangle in Java.

Checklist

• Code follows the style guidelines of this project
• Comments added for better code readability
• Documentation updated (if applicable)
• No new warnings generated
• Added appropriate JavaDoc comments

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Happy Hacktoberfest 2025! 🎉