optisort(A, Cs, D) :-
	between(0, inf, N),
	optitree(A, N, D),
	findall(X, (ord_list(D, X0), append(Cs, X0, X)), Css),
	forall(member(C, Css), (ord_transitives(C, C0), complete_ord(A, C0))),
	!.

optitree(_, 0, D) :-
	D = done.
optitree(Ls, N, D) :-
	N > 0,
	member(A, Ls),
	member(B, Ls),
	A \= B,
	N0 is N - 1,
	between(0, N0, N1),
	between(0, N0, N2),
	optitree(Ls, N1, T1),
	optitree(Ls, N2, T2),
	D = compare(A, B, T1, T2).

ord_list(done, []).
ord_list(compare(A,B,T1,_), [A<B|Rs]) :-
	ord_list(T1,Rs).
ord_list(compare(A,B,_,T2), [B<A|Rs]) :-
	ord_list(T2,Rs).

complete_ord(Ls, Cs) :-
	forall((member(A,Ls), member(B,Ls), A \= B), (member(A<B, Cs); member(B<A, Cs))).

ord_transitives(Cs, Ds) :-
	findall(X, (ord_transitive(Cs, X), \+ member(X, Cs)), Ts),
	ord_transitives_(Cs, Ts, Ds).

ord_transitives_(Cs, [], Cs).
ord_transitives_(Cs, Ts, Ds) :-
	Ts \= [],
	append(Cs, Ts, Cs0),
	ord_transitives(Cs0, Ds).


ord_transitive(Cs, A<C) :-
	member(A<B, Cs),
	member(B<C, Cs).