97 lines
2.1 KiB
Perl
97 lines
2.1 KiB
Perl
|
/*-------------------------------------------------------------------------*/
|
||
|
|
/* Benchmark (Finite Domain) */
|
||
|
|
/* */
|
||
|
|
/* Name : queens.pl */
|
||
|
|
/* Title : N-queens problem */
|
||
|
|
/* Original Source: P. Van Hentenryck's book */
|
||
|
|
/* Adapted by : Daniel Diaz for GNU Prolog */
|
||
|
|
/* Date : January 1993 */
|
||
|
|
/* */
|
||
|
|
/* Put N queens on an NxN chessboard so that there is no couple of queens */
|
||
|
|
/* threatening each other. */
|
||
|
|
/* */
|
||
|
|
/* Solution: */
|
||
|
|
/* N=4 [2,4,1,3] */
|
||
|
|
/* N=8 [1,5,8,6,3,7,2,4] */
|
||
|
|
/* N=16 [1,3,5,2,13,9,14,12,15,6,16,7,4,11,8,10] */
|
||
|
|
/*-------------------------------------------------------------------------*/
|
||
|
|
|
||
|
|
|
||
|
|
q:- get_fd_labeling(Lab), write('N ?'), read_integer(N),
|
||
|
|
statistics(runtime,_),
|
||
|
|
queens(N,L,Lab), statistics(runtime,[_,Y]),
|
||
|
|
write(L), nl,
|
||
|
|
write('time : '), write(Y), nl.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
queens(N,L,Lab):-
|
||
|
|
fd_set_vector_max(N),
|
||
|
|
length(L,N),
|
||
|
|
fd_domain(L,1,N),
|
||
|
|
safe(L),
|
||
|
|
lab(Lab,L).
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
safe([]).
|
||
|
|
|
||
|
|
safe([X|L]):-
|
||
|
|
noattack(L,X,1),
|
||
|
|
safe(L).
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
noattack([],_,_).
|
||
|
|
|
||
|
|
/*
|
||
|
|
% faster than the original PVH's version
|
||
|
|
|
||
|
|
noattack([Y|L],X,I):-
|
||
|
|
I1 is I+1,
|
||
|
|
noattack(L,X,I1),
|
||
|
|
diff(X,Y,I).
|
||
|
|
*/
|
||
|
|
|
||
|
|
noattack([Y|L],X,I):-
|
||
|
|
diff(X,Y,I),
|
||
|
|
I1 is I+1,
|
||
|
|
noattack(L,X,I1).
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
diff(X,Y,I):-
|
||
|
|
fd_tell(diff(X,Y,I)).
|
||
|
|
|
||
|
|
/*
|
||
|
|
diff(X,Y,I):-
|
||
|
|
X#\=Y,
|
||
|
|
X#\=Y+I,
|
||
|
|
X+I#\=Y.
|
||
|
|
*/
|
||
|
|
|
||
|
|
lab(normal,L):-
|
||
|
|
fd_labeling(L).
|
||
|
|
|
||
|
|
lab(ff,L):-
|
||
|
|
fd_labelingff(L).
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
get_fd_labeling(Lab):-
|
||
|
|
argument_counter(C),
|
||
|
|
get_labeling1(C,Lab).
|
||
|
|
|
||
|
|
|
||
|
|
get_labeling1(1,normal).
|
||
|
|
|
||
|
|
get_labeling1(2,Lab):-
|
||
|
|
argument_value(1,Lab).
|
||
|
|
|
||
|
|
|
||
|
|
:- initialization(q).
|