====== Programowanie - Lista 4 ======
===== Zadanie 1. =====
<code prolog>
length2(X,N):-
	length2(X,N,[],0).
length2(X,N,Y,N):-
	reverse(Y,X).
length2(X,N,Y,M):-
	M2 is M+1,
	Y2=[_|Y],
	nonvar(N),!,
	N>=M,
	length2(X,N,Y2,M2),!.
length2(X,N,Y,M):-
	M2 is M+1,
	Y2=[_|Y],
	nonvar(X),!,
	length2(X,N,Y2,M2),!.
length2(X,N,Y,M):-
	M2 is M+1,
	Y2=[_|Y],
	length2(X,N,Y2,M2).
</code>


===== Zadanie 2. =====
<code prolog>
connection(warszawa,lodz).
connection(warszawa,zakopane).
connection(warszawa,wroclaw).
connection(wroclaw,legnica).
connection(lodz,krakow).
connection(zakopane,krakow).

road(X,Y):-
	connection(X,Y).
road(X,Y):-
	connection(Y,X).

trip(X,Y,Z):-
	trip(X,Y,Z,[Y]).
trip(X,_,[X|Z],[X|Z]).
trip(X,Y,Z,[H|S]):-
	road(M,H),
	\+member(M,[H|S]),
	trip(X,Y,Z,[M,H|S]).
</code>
===== Zadanie 3. =====
<code prolog>
rbin( [0] ).
rbin( X ):-
        rbin( Z ),
        rinc( Z, X ).

rinc( [], [1] ):-!.
rinc( [0|T], [1|T] ):-!.
rinc( [1|T], [0|T1] ):-!, 
        rinc( T, T1 ).

bin( [0] ).
bin( X ):-
        bin( Z ),
        inc( Z, X ).

inc( X, X1 ):-
        inc( X, [], X1 ).

inc( [], A, X ):-!,
        rinc( A, XR ),
        reverse( XR, X ).

inc( [H|T], A, X1 ):-
        inc( T, [H|A], X1 ).
</code>