descartes.pl

来自「关系算子的PROLOG描述 prolog人工智能语言」· PL 代码 · 共 17 行

%comb([],B,[]).
%comb([H|T],B,[(H,B)|N]):-comb(T,B,N).

%descartes(A,[],[]).
%descartes(A,[H|T],[X|N]):-comb(A,H,X),descartes(A,T,N).
%
%
%descartes(A,[],[]).
%descartes([],B,[]).
%descartes([HA|TA],[HB|TB],[(HA,HB),X,Y]):length(TA) > 0, length(TB)>0,descartes([HA|TA],[HB],X),descartes([TA],[HB|TB],Y).

comb([ ],B,[ ]).
comb([Ha|Ta],B,[(Ha,B)|N]):-comb(Ta,B,N).

descartes(A,[ ],[ ]).
descartes(A,[Hb|Tb],[Hc|Tc]):-comb(A,Hb,Hc),descartes(A,Tb,Tc).