:- export b/3, test/0.
:- import hitb/2, ambb/3 from usermod.

%:- auto_table.
%:- suppl_table.
:- table b/3, mayHit/2, pro/2, hitBySame/3, hh/2.

:- edb hitb/2.
:- edb ambb/3.

hit(sts(X),Y)   :- hitb(X,Y).
amb(sts(X),Y,Z) :- ambb(X,Y,Z).

:- import ensure_dync_loaded/1 from consult.

:- ensure_dync_loaded('q6.data').

test :- (b(X,Y,Z), writeln(b(X,Y,Z)), fail ; true).

hh(P1, P2) :-
	hitBySame(G, F, P2),
	hitBySame(G, F, P1),
	\+ P1 = P2.

ph(P, Y) :-
	alter21(P, Y).

alter21(P, Y) :- hit(P, Y).
alter21(P, Y) :- pro(P, Y).

b(P, sts(N), NewM) :-
	b(O, P, M),
	NewM is M + 1,
	hh(P, sts(N)),
	tnot(b(X, sts(N), _)).

hitBySame(G, F, P) :-
	ph(P, G),
	ph(P, F),
	\+ G = F.

pro(Q, W) :-
	amb(Q, W, _),
	mayHit(Q, W).

b(sts(Start), sts(Start), 0) :-
	Start = 2.

mayHit(Q, W) :-
	hit(Q, Y),
	hit(P, W),
	hit(P, Y),
	\+ P = Q,
	\+ Y = W.