On top you see an applet for the well-known queens problem: putting n queens on a n x n chessboard such that none of them is able to capture any other using the standard chess queen's moves.

You can try to find a solution yourself by just clicking on the chessbaord: left mousebutton sets a queen, right mousebutton remove a queen. You get informed when a queen attacks another.
In the upper-right corner you can set the dimension of the chessboard. Below you can start the automatic solver where 'step by step' means that (after a solution was found) you have to click the next button the get another solution, while the automatic mode waits the defined time before calculation continues.
The 'count button' just counts how many solutions are there for the specified chessboard dimension. For n > 10 this takes a lot of time... :-(

This site is part of Sunshine's Homepage