CODEWITHSUNDEEP
prolog
pen00
pen00

Reputation: 25

Prolog query with the use of conditional cut

Iv'e been having problems with a prolog query that has some conditions hard to understand at first glance.

sameSum([L], V) :- !, sumlist(L,V). 
sameSum([L|R], V) :- sumlist(L,V),sameSum(R,V). 
sumlist([H],H) :- !.
sumlist([X|R],V) :- sumlist(R,Z), V is X+Z.

The query that is asked to be evaluated is:

?-sameSum([[6,7,2], [1,5,9], [8,3,4]], V). 
?-sameSum([[6,4,1,2], [1,12], [8,5]], V). 
?-sameSum([[6,7], [1,12], [8,5]], 13). 
?-sameSum([],V).

Thank you in advance for the big help.

Upvotes: 2

Views: 76

Answers (1)

false
false

Reputation: 10102

There is no need for any cuts here, instead:

sameSum([], _V). 
sameSum([L|R], V) :-
   % L = [_|_],     % maybe 
   sumlist(L,V),
   sameSum(R,V). 

sumlist([],0).
sumlist([X|R],V) :-
   sumlist(R,Z),
   V is X+Z.

Note that your original definition failed for the last case you gave.

Upvotes: 3

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