Place N queens on N×N board.

Overview

Place N queens on N×N board.

Example 

  void backtrack(List<Integer> path, int start) {
    // Add current path to results
    for (int i = start; i < n; i++) {
        path.add(i);
        backtrack(path, i + 1);
        path.remove(path.size() - 1);
    }
}

Common Use Cases

  • Combinatorial generation
  • Constraint satisfaction
  • Game solving

Pitfalls to Avoid

  • Missing base case
  • Not pruning invalid branches early
  • Dynamic programming
  • DFS on graphs

Best Practices

  • Understand when to use n-queens versus simpler alternatives
  • Write unit tests covering edge cases and failure paths
  • Follow Java conventions and prefer standard library APIs when available
  • Profile before optimizing — measure impact in your specific workload