Jip J. Dekker
f2a1c4e389
git-subtree-dir: software/mza git-subtree-split: f970a59b177c13ca3dd8aaef8cc6681d83b7e813
50 lines
1.1 KiB
MiniZinc
50 lines
1.1 KiB
MiniZinc
% RUNS ON mzn20_fd
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% RUNS ON mzn-fzn_fd
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% RUNS ON mzn20_fd_linear
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% RUNS ON mzn20_mip
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% n-queens example in Zinc using IP techniques
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% By Ralph Becket
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% MiniZinc version
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% Peter Stuckey September 30 2006
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int: n = 8;
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set of int: rg = 0 .. n-1;
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array [rg, rg] of var 0 .. 1: q;
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%
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% Every row and column has exactly one queen.
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% Every diagonal has at most one queen.
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%
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constraint forall (i in rg) (
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( sum (j in rg) (q[i, j]) = 1 )
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/\ ( sum (j in rg) (q[j, i]) = 1 )
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/\ ( sum (j, k in rg where j - k = i) (q[j, k]) <= 1 )
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/\ ( sum (j, k in rg where j - k = - i) (q[j, k]) <= 1 )
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/\ ( sum (j, k in rg where j - k = i) (q[n - 1 - j, k]) <= 1 )
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/\ ( sum (j, k in rg where j - k = - i) (q[n - 1 - j, k]) <= 1 )
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);
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%
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% Find the first solution.
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%
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solve ::
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int_search(
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array1d(1..n*n, q),
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first_fail,
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indomain_min,
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complete
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)
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satisfy;
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output ["8 queens, IP version:"] ++
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[ if j = 0 then "\n" else "" endif ++
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if fix(q[i, j]) = 1 then "Q " else ". " endif
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| i, j in rg
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] ++
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[ "\n" ];
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