Here is the interview question prompt, presented for reference.

N-Queen Problem: The Chessboard Conundrum

Imagine stepping into an interview room, and the interviewer asks you to solve the N-Queen problem. It's a modern take on the classic 8-Queen Puzzle, where you place queens on a chessboard in such a way that none can attack another. Here's a complete guide to understanding the problem and constraints.

The Basic Rules of Chessboard and Queens

First, let's get our chess terminology straight. A queen in chess can move horizontally, vertically, and diagonally. Your task is to place n queens on an n x n chessboard in such a way that none of the queens are in a position to attack each other.

Key Assumptions

• Square Board: The chessboard will always be square-shaped.
• Solution Exists: For n > 3, at least one non-attacking arrangement of queens exists.

Constraints to Keep in Mind

Board Size Limitations

• Maximum value of n: The board can have up to 100 rows and columns.
• Minimum value of n: The board must have at least 4 rows and columns.

Performance Expectations

• Time Complexity: Your solution should aim to have a time complexity of O(n^2).
• Space Complexity: Keep the space complexity at O(n).

Example: Solving a 4x4 Board

For a 4x4 chessboard, you could place the queens like so (Q represents a queen, and . represents an empty space):

. Q . .
. . . Q
Q . . .
. . Q .

Here, no two queens threaten each other. And voila, you've successfully solved the 4-queen problem.

Grasp these guidelines well, and you'll be several moves ahead in your coding interview.

You can see the full challenge with visuals at this link.