% A Prolog program to find people's lover
% --------------------------------

man(george). man(jack). man(tony).
woman(lucy). woman(fiona). woman(peggy).

% % A man can only fall in love with one woman
% % Women are already in different rooms and they like to eat different foods
uniq(A, B, C) :- woman(A), woman(B), woman(C), \+A=B, \+A=C, \+B=C.

% % Clue 1：Room1 has bananas, Peggy isn't in Room1
clue1(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana) :-
  R1=Banana, \+R1=peggy.

% % Clue 2：Tony's lover likes orange，Lucy doesn't like Tony
clue2(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana) :-
  Orange=TL, \+TL=lucy.

% % Clue 3：Fiono doesn't like bananas
clue3(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana) :-
  Banana=fiona.

% % Clue 4：Jack's lover is in Room2 and she likes apple
clue4(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana) :-
  JL=R2, JL=Apple.

% % Clue 5：Room3 has oranges
clue5(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana) :-
  R3=Orange.

% % Show these people’s lover
showLovers(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana) :-
  write("George’s lover is: "), write(GL), nl,
  write("Jack’s lover is: "), write(JL), nl,
  write("Tony’s lover is: "), write(TL), nl,
  write(R1), write(" in Room1"), nl,
  write(R2), write(" in Room2"), nl,
  write(R3), write(" in Room3"), nl,
  write(Apple), write(" likes apple"), nl,
  write(Orange), write(" likes orange"), nl,
  write(Banana), write(" likes banana"), nl.

% % Here we go
findLovers(GL, JL, TL) :-
  uniq(R1, R2, R3),
  uniq(Apple, Orange, Banana),
  uniq(GL, JL, TL),
  clue1(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana),
  clue2(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana),
  clue3(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana),
  clue4(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana),
  clue5(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana),
  showLovers(GL, JL, TL, R1, R2, R3, Apple, Orange, Banana).

% % Answers:
% % George loves Fiona(in Room1, she likes banana)
% % Jack loves Lucy(in Room2, she likes apple)
% % Tony loves Peggy(in Room3, she likes orange)