Create N-Queens.cpp

[hg9336099029]

🐝 Hacktoberfest Contribution – N-Queens II in C++

The N-Queens II problem is a famous backtracking challenge where the goal is to count the number of valid ways to place n queens on an n × n chessboard such that no two queens attack each other. Unlike the standard N-Queens problem, here we only need the total number of distinct solutions, not the actual board layouts.

As part of Hacktoberfest, this repository is dedicated to solving the N-Queens II problem using C++ only. Contributors can:

📝 Add different C++ implementations (recursive backtracking, bitmasking, etc.)

⚡ Optimize existing C++ solutions for faster execution.

📚 Improve readability with comments, clear variable names, and explanations.

✅ Add sample test cases for various values of n.

The objective is to create a comprehensive C++-only resource for N-Queens II, helping learners understand recursion, backtracking, and optimization techniques in C++.

[github-actions]

Thanks for raising the PR, the owner will be review it soon' keep patience, keep contributing>>>!!! make sure you have star ⭐ the repo

[SjxSubham]

@hg9336099029

Maintain PR description format...
raise only valid PR, mention this solution solves which problem of leetcode (also share the problem ID as well)
for reference checkout previously merged PR