/*%%%%	SKAKANI KONEM  (pouziva soubor qsortspe.pro)
*/
:-([qsortspe]).
go(X,Y)		 :-skoky([X/Y],63).

skoky([_/_|Z],0) :-write(Z).
skoky([X/Y|Z],J) :- findall(X1/Y1,gen(X1,Y1,X,Y,Z),L),
		min(L,XM,YM,Z),  
		[X/Y|Z]=Z1, 				
		I is J-1, 	 
	   	skoky([XM/YM|Z1],I).

gen(X1,Y1,X,Y,Z) :-((X1 is X+2,Y1 is Y+1,X1=<8,Y1=<8);
		    (X1 is X+2,Y1 is Y-1,X1=<8,Y1>0);
		    (X1 is X-2,Y1 is Y+1,X1>0,Y1=<8);
		    (X1 is X-2,Y1 is Y-1,X1>0,Y1>0);
		    (X1 is X+1,Y1 is Y+2,X1=<8,Y1=<8);
		    (X1 is X-1,Y1 is Y+2,X1>0,Y1=<8);
		    (X1 is X+1,Y1 is Y-2,X1=<8,Y1>0);
		    (X1 is X-1,Y1 is Y-2,X1>0,Y1>0)),
		   not(member(X1/Y1,Z)).

min(L,XM,YM,Z)	:- member(X/Y,L),	 
		findall(X1/Y1,gen(X1,Y1,X,Y,Z),L1),
		length(L1,N),
		asserta(uloz(X/Y/N)),
		fail.
min(L,XM,YM,Z)  :- sdruz([],M),!,
		qsort(M,M1),
		member(XM/YM/_,M1).

sdruz(U,V)	:- dalsi(X),!,sdruz([X|U],V).
sdruz(U,U).		

dalsi(X/Y/N) 	:- retract(uloz(X/Y/N)),!.

member(X,[X|_]).
member(X,[_|Y]) :- member(X,Y).

length([],0).
length([H|T],X) :- length(T,Y), X is Y +1.