On the 4x4 board below, two white and two black queens are placed so that no queens of one color attack any queen of the other color.

Q Q Q Q

Find a way to place 9 white queens and 9 black queens on an 8x8 chessboard in a similar fashion.

One possible formation:
+---+---+---+---+---+---+---+---+
| W | W | W |   |   |   |   |   |
+---+---+---+---+---+---+---+---+
|   | W | W | W |   |   |   |   |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   | B | B | B |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   | B | B |
+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   | B |
+---+---+---+---+---+---+---+---+
| W | W |   |   |   |   |   |   |
+---+---+---+---+---+---+---+---+
| W |   |   |   |   |   |   |   |
+---+---+---+---+---+---+---+---+
|   |   |   |   | B | B | B |   |
+---+---+---+---+---+---+---+---+

Posted by Dej Mar on 2008-03-25 10:47:24