1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | /* n-queens problem in Comet. From Pascal Van Hentenryck "The OPL Optimization Programming Language", page 34. This Comet model was created by Hakan Kjellerstrand (hakank@gmail.com) Also, see my Comet page: http://www.hakank.org/comet */ // Licenced under CC-BY-4.0 : http://creativecommons.org/licenses/by/4.0/ import cotfd; int t0 = System.getCPUTime(); cout << "Number of Variables: " ; int n = cin.getInt(); range Domain = 1..n; Solver<CP> m(); var <CP>{ int } queens[Domain](m, Domain); Integer num_solutions(0); // exploreall<m> { explore <m> { forall (i in 1..n, j in 1..n : i < j) { m.post(queens[i] != queens[j]); m.post(queens[i] + i != queens[j] + j); m.post(queens[i] - i != queens[j] - j); } } using { labelFF(m); num_solutions++; cout << queens << endl; } cout << "\nnum_solutions: " << num_solutions << endl; int t1 = System.getCPUTime(); cout << "time: " << (t1-t0) << endl; cout << "#choices = " << m.getNChoice() << endl; cout << "#fail = " << m.getNFail() << endl; cout << "#propag = " << m.getNPropag() << endl; |