在 Prolog 中对列表进行分区

我正在尝试创建一个 Prolog 谓词，其中给定一个列表，可以看出该列表是否可以分为两个总和相同的列表。

我有一个工作列表总和谓词，因此我在分区谓词中使用它。我首先尝试对谓词进行编码，以查看列表的第一个元素是否等于列表其余部分的总和 ([2,1,1])。这就是我针对这种情况的情况。

partitionable([X|Y]) :-
   sum([X],SUM),
   sum([Y],SUM2),
   SUM = SUM2.

但是，我收到此错误消息：

ERROR: is/2: Arithmetic: `[]/0' is not a function. 

我想让这篇文章在我深入研究列表其余部分的递归之前就开始工作，尽管我对这条消息的内容感到困惑，因为我还没有写过'[]/0' function。任何帮助表示赞赏。

将列表分成两个不重叠的子序列, 我们用list_subseq_subseq/3:

list_subseq_subseq([]    ,[]    ,[]).
list_subseq_subseq([X|Xs],[X|Ys],Zs) :-
   list_subseq_subseq(Xs,Ys,Zs).
list_subseq_subseq([X|Xs],Ys,[X|Zs]) :-
   list_subseq_subseq(Xs,Ys,Zs).

为了执行整数算术，我们使用clpfd:

:- use_module(library(clpfd)).

让我们把它们放在一起！在下面的示例查询中，我们对列表进行分区[1,2,3,4,5,6,7]:

?- Xs = [1,2,3,4,5,6,7],
   sum(Xs,#=,Total),
   Half*2 #= Total,
   list_subseq_subseq(Xs,Ys,Zs),
   sum(Ys,#=,Half),
   sum(Zs,#=,Half).
  Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [1,2,4,7], Zs = [3,5,6]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [1,2,5,6], Zs = [3,4,7]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [1,3,4,6], Zs = [2,5,7]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [1,6,7]  , Zs = [2,3,4,5]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [2,3,4,5], Zs = [1,6,7]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [2,5,7]  , Zs = [1,3,4,6]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [3,4,7]  , Zs = [1,2,5,6]
; Xs = [1,2,3,4,5,6,7], Total = 28, Half = 14, Ys = [3,5,6]  , Zs = [1,2,4,7]
; false.