The N-Queen problem is simple to describe:
The following is a solution to an 8-Queens problem:
Given:
An N by N chess board.
Task:
Place N queens on the board so that they do not attack each other.
Q Q Q Q Q Q Q Q And here is a solution to a 16-queens problem (be patient, a large table is being loaded .... it may take a while, hopefully less than a minute, but it will be worth waiting for !!!! )
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 1 Q 2 Q 3 Q 4 Q 5 Q 6 Q 7 Q 8 Q 9 Q 0 Q 1 Q 2 Q 3 Q 4 Q 5 Q 6 Q With regard to the solution displayed above, you'll have to trust us here, or else check yourself that this is indeed a feasible solution.
In any case, this puzzle is an interesting combinatorial problem, which with a bit of imagination can be regarded as a typical OR problem. More details on this problem can be found in Kenneth Evans'article on this problem (ORN, January 1977 Issue, p. 13-14)
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