社交圈中like是单向的，你like的人没有义务like回来你。。。
这个实现关键难题是，不采用No逻辑，完全使用正逻辑来实现like, dislike等：
（cnblog也没有Prolog, 依旧使用Scale代替，汗。。）
/* Likes */
/* */
likes(G,X,Y):-
member1(person(X,Xs),G),
member1(Y,Xs).
/* member */
member1(X,[X|_]).
member1(X,[_|Ys]):-
member1(X,Ys).
member2(X,G):-
member1(person(X,_),G).
notmember(_,_,[]).
notmember(G,X,[Y|Ys]):-
notmember(G,X,Ys),
different(G,X,Y).
/*remove from list*/
remove1(X, [X|Xs], Xs).
remove1(X, [H|Xs], [H|Ys]) :-
remove1(X, Xs, Ys).
/*different*/
different(G,X,Y):-
member2(X,G),
remove1(person(X, _), G, Res),
member2(Y,Res).
/* dislikes */
/* */
dislikes(G,X,Y):-
different(G,X,Y),
likes(G,Y,X),
member1(person(X,Xs),G),
notmember(G,Y,Xs).
/*popular*/
popular(G,X):-
member1(person(X,Xfriendlist),G),
alllikes(X,Xfriendlist,G).
/* all elements in [X|Xs] likes Y */
alllikes(Y,[X|Xs],G):-
likes(G,X,Y),
alllikes(Y,Xs,G).
alllikes(_,[],_).
/*outcast*/
outcast(G,X):-
member1(person(X,Xfriendlist),G),
alldislikes(X,Xfriendlist,G).
/* all elements in [X|Xs] dislikes Y */
alldislikes(Y,[X|Xs],G):-
dislikes(G,X,Y),
alldislikes(Y,Xs,G).
alldislikes(_,[],_).
/*friendly*/
friendly(G,X):-
remove1(person(X, _), G, Gg),
wholikes(G,person(X,_),Gg,[],Res),
likesall(G,X,Res).
/*wholikes*/
wholikes(_,_,[],Cont,Cont).
wholikes(G,person(X,_),[person(Y,_)|YYs],Cont,Res):-
likes(G,Y,X),
wholikes(G,person(X,_),YYs,[Y|Cont],Res).
wholikes(G,person(X,_),[person(_,Ys)|YYs],Cont,Res):-
notmember(G,X,Ys),
wholikes(G,person(X,_),YYs,Cont,Res).
/*likesall*/
likesall(_,_,[]).
likesall(G,X,[Y|Ys]):-
likes(G,X,Y),
likesall(G,X,Ys).
/*dislikesall*/
dislikesall(_,_,[]).
dislikesall(G,X,[Y|Ys]):-
dislikes(G,X,Y),
dislikesall(G,X,Ys).
/*hostile*/
hostile(G,X):-
remove1(person(X, _), G, Gg),
wholikes(G,person(X,_),Gg,[],Res),
dislikesall(G,X,Res).
/*admires*/
admires(G,X,Y):-
likes(G,X,Y),
different(G,X,Y).
admires(G,X,Y):-
likes(G,X,Z),
remove1(person(X,_),G,Res),
admires(Res,Z,Y).
notEmpty([_|_]).
isEmpty([]).
checkEvery(_,_,[],Res1,Res1).
checkEvery(G,Xs,[Y|Ys],Res1,Res2):-
member1(Y,Xs),
checkEvery(G,Xs,Ys,Res1,Res2).
checkEvery(G,Xs,[Y|Ys],Res1,Res2):-
notmember(G,Y,Xs),
checkEvery(G,Xs,Ys,[Y|Res1],Res2).
checkGraph(G,X,_,[],[],[]):-
member1(person(X,[]),G).
checkGraph(G,_,_,Lis1,Lis2,Lis1):-
notEmpty(Lis1),
checkEvery(G,Lis1,Lis2,[],Res),
isEmpty(Res).
checkGraph(G,_,Y,Lis1,Lis2,Res):-
notEmpty(Lis1),
checkEvery(G,Lis1,Lis2,[],Res1),
notEmpty(Res1),
member1(Z,Res1),
member1(person(Z,Zs),G),
checkToAdd(G,Zs,Lis2,Cont),
checkGraph(G,Z,Y,[Z|Lis1],Cont,Res).
checkGraph(G,X,Y,Lis1,Lis2,Res):-
isEmpty(Lis1),
member1(person(X,Xs),G),
checkToAdd(G,Xs,Lis2,Cont),
member1(Z,Xs),
notmember(G,Z,Lis1),
checkGraph(G,Z,Y,[X|Lis1],Cont,Res).
checkToAdd(_,[],Lis,Lis).
checkToAdd(G,[X|Xs],Lis,Res):-
member1(X,Lis),
checkToAdd(G,Xs,Lis,Res).
checkToAdd(G,[X|Xs],Lis,Res):-
member1(person(X,_),G),
notmember(G,X,Lis),
checkToAdd(G,Xs,[X|Lis],Res).
notMemOf(G,X,Y):-
checkGraph(G,X,Y,[],[],Res),
notmember(G,Y,Res).
/*indifferent*/
indifferent(G,X,Y):-
different(G,X,Y),
notMemOf(G,X,Y).
/* Same world */
compareLabel([X|Xss],Ys,Label):-
member1((X,Xs),Label),
member1(Xs,Ys),
remove1(Xs,Ys,Yss),
compareLabel(Xss,Yss,Label).
compareLabel([],[],_).
compareFriends(G,H,X,Label):-
member1(person(X,Xs),G),
member1((X,Y),Label),
member1(person(Y,Ys),H),
compareLabel(Xs,Ys,Label).
allFriends(G,H,[X|Xs],Label):-
compareFriends(G,H,X,Label),
allFriends(G,H,Xs,Label).
allFriends(_,_,[],_).
same(G,H,A):-
getPerson(G,X),
getPerson(H,Y),
combine(X,Y,A).
combine([],[],[]).
combine([X|Xs],Ys,[H|T]):-
member1(Y,Ys),pair(H,X,Y),
remove1(Y,Ys,P),
combine(Xs,P,T).
pair((X,Y),X,Y).
getPerson([],[]).
getPerson([person(X,_)|Ys],[X|Xs]):-getPerson(Ys,Xs).
same_world(G,H,Label):-
getPerson(G,P),
same(G,H,Label),
allFriends(G,H,P,Label).