Jip J. Dekker
f2a1c4e389
git-subtree-dir: software/mza git-subtree-split: f970a59b177c13ca3dd8aaef8cc6681d83b7e813
43 lines
1.3 KiB
MiniZinc
43 lines
1.3 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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%-----------------------------------------------------------------------------%
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% Steiner Triples (CSPlib problem 44)
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%
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% March 2008; Mark Wallace, based on the Eclipse version by Joachim Schimpf
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%
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% The following program computes so-called Steiner triplets. These are
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% triplets of numbers from 1 to n such that any two triplets have at most one
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% element in common.
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%
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% One possible solution for n=7 is
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% { {1, 2, 3}, {1, 4, 5}, {1, 6, 7}, {2, 4, 6},
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% {2, 5, 7}, {3, 4, 7}, {3, 5, 6} }.
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%-----------------------------------------------------------------------------%
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n = 7;
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%-----------------------------------------------------------------------------%
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int: n;
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int: nb = n * (n-1) div 6 ;
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array[1..nb] of var set of 1..n: sets;
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constraint forall(i in 1..nb) ( card(sets[i]) = 3 );
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constraint
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forall(i in 1..nb, j in i+1..nb) ( card(sets[i] intersect sets[j]) <= 1 );
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% Symmetry breaking:
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constraint forall(i in 1..nb-1) ( sets[i] >= sets[i+1] );
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solve :: set_search(sets, input_order, indomain_min, complete) satisfy;
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output [ " " ++ show(sets[i]) | i in 1..nb ] ++ ["\n"];
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%-----------------------------------------------------------------------------%
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%-----------------------------------------------------------------------------%
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