使用prolog的clp库:
1 ?- use_module(library(clpfd)).
% library(error) compiled into error 0.00 sec, 9,764 bytes
% library(clpfd) compiled into clpfd 0.05 sec, 227,496 bytes
true.
2 ?- Vars=[A,B,C,D],Vars ins 0..10,sum(Vars,#=,10),label(Vars).
Vars = [0, 0, 0, 10],
A = 0,
B = 0,
C = 0,
D = 10 ;
Vars = [0, 0, 1, 9],
A = 0,
B = 0,
C = 1,
D = 9 ;
Vars = [0, 0, 2, 8],
A = 0,
B = 0,
C = 2,
D = 8 ;
Vars = [0, 0, 3, 7],
A = 0,
B = 0,
C = 3,
D = 7 ;
...
其中
#=表示等于
ins表示在。。范围内
0..10表示0~10之间的整数
label用来搜索所有的可能解。
更新
不用clp库也可以这样实现:
range(X):-
member(X,[0,1,2,3,4,5,6,7,8,9,10]).
ten(A,B,C,D):-
range(A),
range(B),
range(C),
range(D),
10 =:= A + B + C + D.
其中member(X,[0,1,2,3,4,5,6,7,8,9,10])也可以表示成between(0,10,X)