main :-
	statistics(runtime, _),
	knight5_all,
	statistics(runtime, [_,T]),
	write('CPU time = '), write(T), write(' msec'), nl.

knight5_all :-
	knight5(Tour),
%	write(Tour), nl,
	fail.
knight5_all.	

knight5(Tour) :-
	(k(1,1), k(1,2), k(1,3), k(1,4), k(1,5),
	 k(2,1), k(2,2), k(2,3), k(2,4), k(2,5),
	 k(3,1), k(3,2), k(3,3), k(3,4), k(3,5),
	 k(4,1), k(4,2), k(4,3), k(4,4), k(4,5),
	 k(5,1), k(5,2), k(5,3), k(5,4), k(5,5)) -<>
	tour(Tour).

tour(Tour) :-
	k(1, 1),
	tour(1, 1, Tour).

tour(I, J, [(I,J)]).
tour(I, J, [(I,J)|Tour]) :-
	next(I, J, I1, J1),
	k(I1, J1),
	tour(I1, J1, Tour).

next(I, J, I1, J1) :- I1 is I-2, J1 is J-1.
next(I, J, I1, J1) :- I1 is I-2, J1 is J+1.
next(I, J, I1, J1) :- I1 is I-1, J1 is J-2.
next(I, J, I1, J1) :- I1 is I-1, J1 is J+2.
next(I, J, I1, J1) :- I1 is I+1, J1 is J-2.
next(I, J, I1, J1) :- I1 is I+1, J1 is J+2.
next(I, J, I1, J1) :- I1 is I+2, J1 is J-1.
next(I, J, I1, J1) :- I1 is I+2, J1 is J+1.