Peaceable Queens
This task is adapted from following video with Neil Sloane (founder of the On-Line Encyclopedia of Integer Sequences), that you should watch first to learn, how this excellent puzzle works.
You are given a chessboard of custom dimension: size * size. Your goal is to put there as many ♕ and ♛ as possible with these rules of placement:
- only equal numbers of Queens are allowed;
- ♕ must not attack ♛ and vice versa (but they may be under "attack" of the same color Queens).
Your function should return the maximum number of opposite Queens pairs, you could put on the given chessboard according to the restrictions.
Input: Size of the chessboard as integer.
Output: Maximum number of opposite Queens pairs as integer.
Examples:
assert peaceable_queens(1) == 0 assert peaceable_queens(2) == 0 assert peaceable_queens(3) == 1 assert peaceable_queens(4) == 2
