I'm trying to solve a riddle in Prolog. the riddle is: There are two buildings, each one has tree apartments (apartment per floor): one apartment of 3 rooms,one of 4 rooms and one of 5 rooms.
Dana,Joni and Noah lives in building 1. Ron,Gale and Aron lives in building 2.
Joni apartment is higher then Dana and Noah. It means he lives on the third floor of building 1. Noah and Gale lives on the same floor (in different buildings). Ron has a one more room than Aron. Ron lives one floor above Gale. The highest apartment in building 2 is the 5 rooms apartment.
I need to find in which floor everyone lives.
I wrote this code:
solve([dana,building1,F1,R1],[noah,building1,F2,R2],[joni,building1,F3,R3],[gale,building2,F4,R4],[ron,building2,F5,R5],[aron,building2,F6,R6]
) :-
L =[[dana,building1,1,3],[dana,building1,1,4],[dana,building1,1,5],[dana,building1,2,3],[dana,building1,2,4],[dana,building1,2,5],[dana,building1,3,3],[dana,building1,3,4],[dana,building1,3,5]
,[noah,building1,1,3],[noah,building1,1,4],[noah,building1,1,5],[noah,building1,2,3],[noah,building1,2,4],[noah,building1,2,5],[noah,building1,3,3],[noah,building1,3,4],[noah,building1,3,5]
,[joni,building1,1,3],[joni,building1,1,4],[joni,building1,1,5],[joni,building1,2,3],[joni,building1,2,4],[joni,building1,2,5],[joni,building1,3,3],[joni,building1,3,4],[joni,building1,3,5]
,[gale,building1,1,3],[gale,building1,1,4],[gale,building1,1,5],[gale,building1,2,3],[gale,building1,2,4],[gale,building1,2,5],[gale,building1,3,3],[gale,building1,3,4],[gale,building1,3,5]
,[ron,building1,1,3],[ron,building1,1,4],[ron,building1,1,5],[ron,building1,2,3],[ron,building1,2,4],[ron,building1,2,5],[ron,building1,3,3],[ron,building1,3,4],[ron,building1,3,5]
,[aron,building1,1,3],[aron,building1,1,4],[aron,building1,1,5],[aron,building1,2,3],[aron,building1,2,4],[aron,building1,2,5],[aron,building1,3,3],[aron,building1,3,4],[aron,building1,3,5]],
F3 > F2,
F3>F1,
F2 == F4,
R5 == R6-1,
F5 == F4+1,
(F4 == 3, R4 == 5;F5 == 3, R5 == 5; F6 == 3, R6 == 5),
del([dana,building1,F1,R1],L,List1),
del([noah,building1,F2,R2],List1,List2),
del([joni,building1,F3,R3],List2,List3),
del([gale,building2,F4,R4],List3,List4),
del([ron,building2,F5,R5],List4,List5),
del([aron,building2,F6,R6],List5,_).
del(X,L,L1) :-
remove(X,L,L1).
But when I execute the query:
solve([dana,building1,F1,R1],[noah,building1,F2,R2],[joni,building1,F3,R3],[gale,building2,F4,R4],[ron,building2,F5,R5],[aron,building2,F6,R6]).
I get:
"Error 22 : Instantiation Error"
anyone? I don't understand what I do wrong.
I finally did it. This is the answer:
solve([dana,building1,F1,R1],
[noah,building1,F2,R2],
[joni,building1,F3,R3],
[gale,building2,F4,R4],
[ron,building2,F5,R5],
[aron,building2,F6,R6]) :-
assign([1,2,3],[F1,F2,F3]),
assign([1,2,3],[F4,F5,F6]),
assign([3,4,5],[R1,R2,R3]),
assign([3,4,5],[R4,R5,R6]),
F3 > F2,
F3>F1,
F2 =:= F4,
R5 =:= R6-1,
F5 =:= F4+1,
( F4 =:= 3, R4 =:= 5
; F5 =:= 3, R5 =:= 5
; F6 =:= 3, R6 =:= 5
).
assign(_,[]).
assign(Digs,[D|Vars]):-
del(D,Digs,Digs1),
assign(Digs1,Vars).
del(X,L,L1):-
remove(X,L,L1).