Added N-Queens Problem Solution

[sujanrupu]

📄 Summary

This PR adds the C++ implementation of the N-Queens problem to the DSA repository.
It includes a clean backtracking-based solution that finds all valid ways to place N queens on an N×N chessboard such that no two queens attack each other.

📚 Details

• Problem Link: https://leetcode.com/problems/n-queens/
• Approach: Backtracking — place queens column by column, validating safe positions before recursion.
• File Added:
  • Code.cpp

⚙️ Complexity

• Time Complexity: O(N!)
• Space Complexity: O(N²)

✅ Checklist

• Added problem solution in C++
• Verified correctness with sample inputs
• Followed clean and modular coding practices

[github-actions]

🎉 Welcome to Hacktoberfest 2025, @sujanrupu! 🎃

Thank you for your first contribution to our DSA repository! Here's what happens next:

🔍 Automatic Checks

• ✅ Code Validation: Passed
• 🧪 Compilation Tests: Passed

📋 Next Steps

🎯 Great job! Your code compiled successfully. Maintainers @admirerr and @kartikey2991 will review your PR soon.

🎁 What You Get

• 🏆 Hacktoberfest Credit: This PR counts toward your 6 PR goal for exclusive T-shirt + Tree!
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💡 Tips for Success

• Follow our Contributing Guidelines
• Add comments explaining your algorithm
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Welcome to the community! 🚀

[github-actions]

🤖 Automated PR Status

🔍 Code Validation

✅ Passed - File naming and structure look good!

🧪 Compilation Tests

✅ Passed - All code compiles successfully!

📋 Overall Status

🎉 Ready for Review - Your PR has passed all automated checks!
👥 Maintainers have been notified for review.

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[admirerr]

Approved