I have the grasp of the idea of crypt arithmetic and addition but I cannot figure out how to do a multiplication crypt arithmetic problem. It's simply TWO*SIX=TWELVE or something along those lines without the middle additional part of the multiplication problem given. I couldn't find anything online and I already found some constraints for the problem but nothing to leads me to some answers. Not sure where to ask this and thought this would be the best place.
I want to know how to solve a multiplication crypt arithmetic problem.
I already concluded:
T W O
* S I X
_________________
T W E L V E
T \= 0 which also means S \= 0
T is 1-6
E is (O*X) mod 10
O or X cannot be 0 or 1 since E has to be different and 0 or 1 gives the same value
as either O or X.
EDIT: I was using the generate and test method
solve(T,W,O,S,I,X,E,L,V) :-
X = [T,W,O,S,I,X,E,L,V],
Digits = [0,1,2,3,4,5,6,7,8,9],
assign_digits(X, Digits),
T > 0,
S > 0,
100*T + 10*W + O * 100*S + 10*I + X =:=
100000*T + 10000*W + 1000*E + 100*L + 10*V + E,
write(X).
select(X, [X|R], R).
select(X, [Y|Xs], [Y|Ys]):- select(X, Xs, Ys).
assign_digits([], _List).
assign_digits([D|Ds], List):-
select(D, List, NewList),
assign_digits(Ds, NewList).
Trivially to do with constraint logic programming. For example, in ECLiPSe Prolog:
:- lib(ic).
puzzle(Vars) :-
[T,W,O,S,I,X,E,L,V] = Vars,
Vars :: 0..9,
alldifferent(Vars),
T #> 0, S #> 0,
(100*T + 10*W + O) * (100*S + 10*I + X) #=
100000*T + 10000*W + 1000*E + 100*L + 10*V + E,
labeling(Vars).
First solution:
[eclipse]: puzzle([T,W,O,S,I,X,E,L,V]).
T = 1
W = 6
O = 5
S = 9
I = 7
X = 2
E = 0
L = 3
V = 8
Yes (0.01s cpu, solution 1, maybe more) ?
There are 3 different solutions:
[eclipse]: puzzle([T,W,O,S,I,X,E,L,V]), writeln([T,W,O,S,I,X,E,L,V]), fail.
[1, 6, 5, 9, 7, 2, 0, 3, 8]
[2, 1, 8, 9, 6, 5, 0, 3, 7]
[3, 4, 5, 9, 8, 6, 0, 1, 7]
No (0.02s cpu)
Update - translation to SWI Prolog:
:- use_module(library(clpfd)).
puzzle(Vars) :-
[T,W,O,S,I,X,E,L,V] = Vars,
Vars ins 0..9,
all_different(Vars),
T #> 0, S #> 0,
(100*T + 10*W + O) * (100*S + 10*I + X) #=
100000*T + 10000*W + 1000*E + 100*L + 10*V + E,
label(Vars).