quite easy to place four chess queens on a 4x4 board to leave one
unattacked vacant cell - see the diagram at right. The only unattacked
cell is marked with a red dot. This cell can't be reached by any of
the queens according to their allowed moves.
Your task is to place five chess queens on a 5x5 board in such a way
that a maximum number of vacant cells are unattacked.
the way, if you've forgotten the chess queen's moves the diagram at
left will remind it to you. It shows that you may move the queen in
any of the eight directions and on any number of the vacant cells.
For more convenient solving you may print out the board, and use five
quarters as queens and some pennies to mark the unattacked vacant