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% Version: CMPL 1.1
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% The contents of this file are subject to the Cisco-style Mozilla Public
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% The Original Code is  The ECLiPSe Constraint Logic Programming System. 
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:- lib(ic).

queens(N, Board) :-
	length(Board, N),
	Board :: 1..N,
	( fromto(Board, [Q1|Cols], Cols, []) do
	    ( foreach(Q2, Cols), count(Dist,1,_), param(Q1) do
		noattack(Q1, Q2, Dist)
	    )
	).

noattack(Q1,Q2,Dist) :-
	Q2 #\= Q1,
	Q2 - Q1 #\= Dist,
	Q1 - Q2 #\= Dist.


