Completed Backtracking

[JainShubham23]

No description provided.

[super30admin]

Strengths:

• The N-Queens solution is correct and follows the backtracking approach.
• The code is well-commented and easy to understand.
• The helper functions are appropriately used to modularize the code.

Areas for Improvement:

• The time complexity claim for N-Queens is incorrect. It should be O(n * n!) rather than O(n^2). Please review the time complexity analysis for backtracking algorithms.
• In the isValid function, you are checking the entire column above the current row. Since we are placing queens row by row, there is no need to check below the current row, which you are not doing, so it's correct. However, note that the while loop for the column checks from the current row upwards (r>=0) which is correct.
• Consider using a list of booleans for columns and diagonals to avoid the O(n) validity check. This would reduce the time complexity per placement to O(1), but the overall time complexity would still be O(n!) and the space would increase by O(n) for these arrays. This is an optimization that can be done but is not necessary for n<=9.

Overall, the solution is correct and well-written. The main issue is the incorrect time complexity analysis.