28
$\begingroup$

What is the maximum number of queens that can be placed on a standard 8x8 chessboard such that no one of them is capable of attacking any of the others in a single move?

$\endgroup$
30
$\begingroup$

8.

Because:

Obviously, you can't have more than 8, since you would have a row (and column) with more than one queen on it.

According to Wolfram-Alpha, there are

12 unique solutions, plus an additional 80 solutions from rotation/reflection.

One possible solution is:

8 Queens not attacking each other.  Image from codereview.stackexchange.com

A list (and images!) of all

12 base solutions can be found both at the above Wolfram-Alpha link and Wikipedia. (Thank you Kevin for the link).

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.