使用列表 Prolog 的河内塔
Towers of Hanoi using Lists Prolog
我知道已经有涵盖此内容的示例程序，但我需要用 6 个光盘以特定方式完成汉诺塔的任务，但我遇到了麻烦。我目前拥有的代码如下：
s([],[],[]).
initial(s([1,2,3,4,5,6], [], [])).
goal(s([],[],[1,2,3,4,5,6])).
我还有 26 行代码来验证有效状态，但是我自己测试了该代码并且它有效，我遇到的问题是创建代码以将光盘从一个堆栈移动到另一个堆栈。下面是我尝试执行的示例查询示例：
changeState((s([A | B],[],[])), s([C], [D], [])) :- C is B, D is A.
?- changeState((s([1,2,3,4,5,6],[],[])), s([2,3,4,5,6], [1], [])).
所以这将是最开始的地方，所有 6 个盘子都在第一堆上，我想将最上面的盘子移到第二堆。本质上，我希望能够从列表中删除第一个元素，并将其添加到另一个列表中，无论它是否为空。
编辑：
得到我需要的上述工作，现在我只需要帮助修复遍历谓词。完整代码如下：
%Post A, Post B, Post C
s([],[],[]).
initial(s([1,2,3,4,5,6], [], [])).
goal(s([],[],[1,2,3,4,5,6])).
valid([], _).
valid([H|_], X) :-
X < H.
changeState((s([A|T1], T2, T3)), s(T1, [A|T2], T3)) :-
valid(T2, A).
changeState((s([A|T1], T2, T3)), s(T1, T2, [A|T3])) :-
valid(T3, A).
changeState(s(T1, [A|T2], [B|T3]), s(T1, T2, [A,B|T3])) :-
valid(A,B).
changeState(s([A|T1], T2, [B|T3]), s([B,A|T1], T2, T3)) :-
valid(B, A).
changeState(s(T1, [A|T2], [B|T3]), s(T1, [B,A|T2], T3)) :-
valid(B, A).
changeState(s([A|T1], [B|T2], T3), s(T1, [A,B|T2], T3)) :-
valid(A,B).
changeState(s([A|T1], [B|T2], T3), s([B,A|T1], T2, T3)) :-
valid(B,A).
changeState(s([A|T1], T2, [B|T3]), s(T1, T2, [A,B|T3])) :-
valid(A,B).
changeState(s(T1, [A|T2], T3), s(T1, T2, [A|T3])) :-
valid(T3, A).
changeState(s(T1, [A|T2], T3), s([A|T1], T2, T3)) :-
valid(T1, A).
changeState(s(T1, T2, [A|T3]), s(T1, [A|T2], T3)) :-
valid(T2, A).
changeState(s(T1, T2, [A|T3]), s([A|T1], T2, T3)) :-
valid(T1, A).
traverse(StartNode,Sol,_) :- goal(StartNode), Sol = [StartNode].
traverse(StartNode,Sol,Visit) :- changeState(StartNode, NextNode),
not(member(NextNode, Visit)),
traverse(NextNode, PartialSol, [NextNode|Visit]),
Sol = [StartNode | PartialSol].
当我运行这个查询时：
?- traverse((s([1,2,3,4,5,6], [], [])), Sol, s([1,2,3,4,5,6], [], [])).
我得到这个输出：
在我收到这些回复大约 10 分钟后，我已经离开了它 运行ning，但它仍然没有产生新的回复，所以它只是继续 运行 一遍又一遍。如上所述，该程序的重点是使用列表解决具有 6 个圆盘的汉诺塔问题。对于那些不熟悉河内塔的人，您基本上需要将所有圆盘从第一叠移动到最后的第三叠。您一次只能移动 1 个圆盘，并且不能将较大的圆盘放在较小的圆盘之上。因此，您从 (s([1,2,3,4,5,6], [], [])) 开始，每个列表分别代表 Stack A、Stack B、Stack C，目标是以 ( s([], [], [1,2,3,4,5,6]))。我通过 changeState 谓词手动 运行 完成整个解决方案（63 次移动），并且所有 t运行sitions 都被接受，所以问题出在 t运行sverse 谓词上。 t运行sverse 谓词旨在显示导致解决方案的所有步骤以及所有可能的解决方案。它还意味着停止循环，因此它不仅仅是一遍又一遍地交换相同的 2 个光盘。不能完全弄清楚我的谓词有什么问题导致我得到这个输出，我对序言还是很陌生，所以我很感激任何帮助！
您可以在此处使用 统一 而不是 is/2（通常用于计算表达式）。
例如，假设第二座塔是空的，我们可以定义从第一座塔到第二座塔的移动：
changeState((s([A|T1],[], T3)), s(T1, [A], T3)).
或者我们可以将一个元素移动到非空的第二个塔，假设堆栈的顶部是一个更大的元素：
changeState(s([A|T1], [B|T2], T3), s(T1, [A,B|T2], T3)) :-
A < B.
以上将产生总共 12 条规则：3 个来源，乘以 2 个目的地，乘以 2 种可能性（空目的地与非空目的地）。这不是很优雅。我们可以构造一个辅助谓词来检查目标堆栈是否有效，其中：
valid_stack([], _).
valid_stack([H|_], X) :-
X < H.
那么我们可以将上面的两条规则压缩成：
changeState((s([A|T1], T2, T3)), s(T1, [A|T2], T3)) :-
valid_stack(T2, A).
因此，这将产生六个规则：三个来源和两个目的地。
因此我们不再需要验证移动，因为如果 changeState 成功，那么建议的移动是可能的 给定 原始状态是有效的。
但这不是完整的解决方案（我将其余部分作为练习）。您将需要一种机制来枚举可能的移动，并确保您不会陷入循环（例如在两座塔之间不断移动圆盘）。
使用 traverse/3 谓词后，我们获得了目标移动列表：
?- traverse(s([1,2,3,4,5,6], [], []), S, [s([1,2,3,4,5,6], [], [])]).
S = [s([1, 2, 3, 4, 5, 6], [], []), s([2, 3, 4, 5, 6], [1], []), s([3, 4, 5, 6], [1], [2]), s([1, 3, 4, 5|...], [], [2]), s([3, 4, 5|...], [], [1, 2]), s([4, 5|...], [3], [1, 2]), s([1|...], [3], [2]), s([...|...], [...|...], [...]), s(..., ..., ...)|...] [write]
S = [s([1, 2, 3, 4, 5, 6], [], []), s([2, 3, 4, 5, 6], [1], []), s([3, 4, 5, 6], [1], [2]), s([1, 3, 4, 5, 6], [], [2]), s([3, 4, 5, 6], [], [1, 2]), s([4, 5, 6], [3], [1, 2]), s([1, 4, 5, 6], [3], [2]), s([4, 5, 6], [1, 3], [2]), s([2, 4, 5, 6], [1, 3], []), s([1, 2, 4, 5, 6], [3], []), s([2, 4, 5, 6], [3], [1]), s([4, 5, 6], [2, 3], [1]), s([1, 4, 5, 6], [2, 3], []), s([4, 5, 6], [1, 2, 3], []), s([5, 6], [1, 2, 3], [4]), s([1, 5, 6], [2, 3], [4]), s([5, 6], [2, 3], [1, 4]), s([2, 5, 6], [3], [1, 4]), s([1, 2, 5, 6], [3], [4]), s([2, 5, 6], [1, 3], [4]), s([5, 6], [1, 3], [2, 4]), s([1, 5, 6], [3], [2, 4]), s([5, 6], [3], [1, 2, 4]), s([3, 5, 6], [], [1, 2, 4]), s([1, 3, 5, 6], [], [2, 4]), s([3, 5, 6], [1], [2, 4]), s([2, 3, 5, 6], [1], [4]), s([1, 2, 3, 5, 6], [], [4]), s([2, 3, 5, 6], [], [1, 4]), s([3, 5, 6], [2], [1, 4]), s([1, 3, 5, 6], [2], [4]), s([3, 5, 6], [1, 2], [4]), s([5, 6], [1, 2], [3, 4]), s([1, 5, 6], [2], [3, 4]), s([5, 6], [2], [1, 3, 4]), s([2, 5, 6], [], [1, 3, 4]), s([1, 2, 5, 6], [], [3, 4]), s([2, 5, 6], [1], [3, 4]), s([5, 6], [1], [2, 3, 4]), s([1, 5, 6], [], [2, 3, 4]), s([5, 6], [], [1, 2, 3, 4]), s([6], [5], [1, 2, 3, 4]), s([1, 6], [5], [2, 3, 4]), s([6], [1, 5], [2, 3, 4]), s([2, 6], [1, 5], [3, 4]), s([1, 2, 6], [5], [3, 4]), s([2, 6], [5], [1, 3, 4]), s([6], [2, 5], [1, 3, 4]), s([1, 6], [2, 5], [3, 4]), s([6], [1, 2, 5], [3, 4]), s([3, 6], [1, 2, 5], [4]), s([1, 3, 6], [2, 5], [4]), s([3, 6], [2, 5], [1, 4]), s([2, 3, 6], [5], [1, 4]), s([1, 2, 3, 6], [5], [4]), s([2, 3, 6], [1, 5], [4]), s([3, 6], [1, 5], [2, 4]), s([1, 3, 6], [5], [2, 4]), s([3, 6], [5], [1, 2, 4]), s([6], [3, 5], [1, 2, 4]), s([1, 6], [3, 5], [2, 4]), s([6], [1, 3, 5], [2, 4]), s([2, 6], [1, 3, 5], [4]), s([1, 2, 6], [3, 5], [4]), s([2, 6], [3, 5], [1, 4]), s([6], [2, 3, 5], [1, 4]), s([1, 6], [2, 3, 5], [4]), s([6], [1, 2, 3, 5], [4]), s([4, 6], [1, 2, 3, 5], []), s([1, 4, 6], [2, 3, 5], []), s([4, 6], [2, 3, 5], [1]), s([2, 4, 6], [3, 5], [1]), s([1, 2, 4, 6], [3, 5], []), s([2, 4, 6], [1, 3, 5], []), s([4, 6], [1, 3, 5], [2]), s([1, 4, 6], [3, 5], [2]), s([4, 6], [3, 5], [1, 2]), s([3, 4, 6], [5], [1, 2]), s([1, 3, 4, 6], [5], [2]), s([3, 4, 6], [1, 5], [2]), s([2, 3, 4, 6], [1, 5], []), s([1, 2, 3, 4, 6], [5], []), s([2, 3, 4, 6], [5], [1]), s([3, 4, 6], [2, 5], [1]), s([1, 3, 4, 6], [2, 5], []), s([3, 4, 6], [1, 2, 5], []), s([4, 6], [1, 2, 5], [3]), s([1, 4, 6], [2, 5], [3]), s([4, 6], [2, 5], [1, 3]), s([2, 4, 6], [5], [1, 3]), s([1, 2, 4, 6], [5], [3]), s([2, 4, 6], [1, 5], [3]), s([4, 6], [1, 5], [2, 3]), s([1, 4, 6], [5], [2, 3]), s([4, 6], [5], [1, 2, 3]), s([6], [4, 5], [1, 2, 3]), s([1, 6], [4, 5], [2, 3]), s([6], [1, 4, 5], [2, 3]), s([2, 6], [1, 4, 5], [3]), s([1, 2, 6], [4, 5], [3]), s([2, 6], [4, 5], [1, 3]), s([6], [2, 4, 5], [1, 3]), s([1, 6], [2, 4, 5], [3]), s([6], [1, 2, 4, 5], [3]), s([3, 6], [1, 2, 4, 5], []), s([1, 3, 6], [2, 4, 5], []), s([3, 6], [2, 4, 5], [1]), s([2, 3, 6], [4, 5], [1]), s([1, 2, 3, 6], [4, 5], []), s([2, 3, 6], [1, 4, 5], []), s([3, 6], [1, 4, 5], [2]), s([1, 3, 6], [4, 5], [2]), s([3, 6], [4, 5], [1, 2]), s([6], [3, 4, 5], [1, 2]), s([1, 6], [3, 4, 5], [2]), s([6], [1, 3, 4, 5], [2]), s([2, 6], [1, 3, 4, 5], []), s([1, 2, 6], [3, 4, 5], []), s([2, 6], [3, 4, 5], [1]), s([6], [2, 3, 4, 5], [1]), s([1, 6], [2, 3, 4, 5], []), s([6], [1, 2, 3, 4, 5], []), s([], [1, 2, 3, 4, 5], [6]), s([1], [2, 3, 4, 5], [6]), s([], [2, 3, 4, 5], [1, 6]), s([2], [3, 4, 5], [1, 6]), s([1, 2], [3, 4, 5], [6]), s([2], [1, 3, 4, 5], [6]), s([], [1, 3, 4, 5], [2, 6]), s([1], [3, 4, 5], [2, 6]), s([], [3, 4, 5], [1, 2, 6]), s([3], [4, 5], [1, 2, 6]), s([1, 3], [4, 5], [2, 6]), s([3], [1, 4, 5], [2, 6]), s([2, 3], [1, 4, 5], [6]), s([1, 2, 3], [4, 5], [6]), s([2, 3], [4, 5], [1, 6]), s([3], [2, 4, 5], [1, 6]), s([1, 3], [2, 4, 5], [6]), s([3], [1, 2, 4, 5], [6]), s([], [1, 2, 4, 5], [3, 6]), s([1], [2, 4, 5], [3, 6]), s([], [2, 4, 5], [1, 3, 6]), s([2], [4, 5], [1, 3, 6]), s([1, 2], [4, 5], [3, 6]), s([2], [1, 4, 5], [3, 6]), s([], [1, 4, 5], [2, 3, 6]), s([1], [4, 5], [2, 3, 6]), s([], [4, 5], [1, 2, 3, 6]), s([4], [5], [1, 2, 3, 6]), s([1, 4], [5], [2, 3, 6]), s([4], [1, 5], [2, 3, 6]), s([2, 4], [1, 5], [3, 6]), s([1, 2, 4], [5], [3, 6]), s([2, 4], [5], [1, 3, 6]), s([4], [2, 5], [1, 3, 6]), s([1, 4], [2, 5], [3, 6]), s([4], [1, 2, 5], [3, 6]), s([3, 4], [1, 2, 5], [6]), s([1, 3, 4], [2, 5], [6]), s([3, 4], [2, 5], [1, 6]), s([2, 3, 4], [5], [1, 6]), s([1, 2, 3, 4], [5], [6]), s([2, 3, 4], [1, 5], [6]), s([3, 4], [1, 5], [2, 6]), s([1, 3, 4], [5], [2, 6]), s([3, 4], [5], [1, 2, 6]), s([4], [3, 5], [1, 2, 6]), s([1, 4], [3, 5], [2, 6]), s([4], [1, 3, 5], [2, 6]), s([2, 4], [1, 3, 5], [6]), s([1, 2, 4], [3, 5], [6]), s([2, 4], [3, 5], [1, 6]), s([4], [2, 3, 5], [1, 6]), s([1, 4], [2, 3, 5], [6]), s([4], [1, 2, 3, 5], [6]), s([], [1, 2, 3, 5], [4, 6]), s([1], [2, 3, 5], [4, 6]), s([], [2, 3, 5], [1, 4, 6]), s([2], [3, 5], [1, 4, 6]), s([1, 2], [3, 5], [4, 6]), s([2], [1, 3, 5], [4, 6]), s([], [1, 3, 5], [2, 4, 6]), s([1], [3, 5], [2, 4, 6]), s([], [3, 5], [1, 2, 4, 6]), s([3], [5], [1, 2, 4, 6]), s([1, 3], [5], [2, 4, 6]), s([3], [1, 5], [2, 4, 6]), s([2, 3], [1, 5], [4, 6]), s([1, 2, 3], [5], [4, 6]), s([2, 3], [5], [1, 4, 6]), s([3], [2, 5], [1, 4, 6]), s([1, 3], [2, 5], [4, 6]), s([3], [1, 2, 5], [4, 6]), s([], [1, 2, 5], [3, 4, 6]), s([1], [2, 5], [3, 4, 6]), s([], [2, 5], [1, 3, 4, 6]), s([2], [5], [1, 3, 4, 6]), s([1, 2], [5], [3, 4, 6]), s([2], [1, 5], [3, 4, 6]), s([], [1, 5], [2, 3, 4, 6]), s([1], [5], [2, 3, 4, 6]), s([], [5], [1, 2, 3, 4, 6]), s([5], [], [1, 2, 3, 4, 6]), s([1, 5], [], [2, 3, 4, 6]), s([5], [1], [2, 3, 4, 6]), s([2, 5], [1], [3, 4, 6]), s([1, 2, 5], [], [3, 4, 6]), s([2, 5], [], [1, 3, 4, 6]), s([5], [2], [1, 3, 4, 6]), s([1, 5], [2], [3, 4, 6]), s([5], [1, 2], [3, 4, 6]), s([3, 5], [1, 2], [4, 6]), s([1, 3, 5], [2], [4, 6]), s([3, 5], [2], [1, 4, 6]), s([2, 3, 5], [], [1, 4, 6]), s([1, 2, 3, 5], [], [4, 6]), s([2, 3, 5], [1], [4, 6]), s([3, 5], [1], [2, 4, 6]), s([1, 3, 5], [], [2, 4, 6]), s([3, 5], [], [1, 2, 4, 6]), s([5], [3], [1, 2, 4, 6]), s([1, 5], [3], [2, 4, 6]), s([5], [1, 3], [2, 4, 6]), s([2, 5], [1, 3], [4, 6]), s([1, 2, 5], [3], [4, 6]), s([2, 5], [3], [1, 4, 6]), s([5], [2, 3], [1, 4, 6]), s([1, 5], [2, 3], [4, 6]), s([5], [1, 2, 3], [4, 6]), s([4, 5], [1, 2, 3], [6]), s([1, 4, 5], [2, 3], [6]), s([4, 5], [2, 3], [1, 6]), s([2, 4, 5], [3], [1, 6]), s([1, 2, 4, 5], [3], [6]), s([2, 4, 5], [1, 3], [6]), s([4, 5], [1, 3], [2, 6]), s([1, 4, 5], [3], [2, 6]), s([4, 5], [3], [1, 2, 6]), s([3, 4, 5], [], [1, 2, 6]), s([1, 3, 4, 5], [], [2, 6]), s([3, 4, 5], [1], [2, 6]), s([2, 3, 4, 5], [1], [6]), s([1, 2, 3, 4, 5], [], [6]), s([2, 3, 4, 5], [], [1, 6]), s([3, 4, 5], [2], [1, 6]), s([1, 3, 4, 5], [2], [6]), s([3, 4, 5], [1, 2], [6]), s([4, 5], [1, 2], [3, 6]), s([1, 4, 5], [2], [3, 6]), s([4, 5], [2], [1, 3, 6]), s([2, 4, 5], [], [1, 3, 6]), s([1, 2, 4, 5], [], [3, 6]), s([2, 4, 5], [1], [3, 6]), s([4, 5], [1], [2, 3, 6]), s([1, 4, 5], [], [2, 3, 6]), s([4, 5], [], [1, 2, 3, 6]), s([5], [4], [1, 2, 3, 6]), s([1, 5], [4], [2, 3, 6]), s([5], [1, 4], [2, 3, 6]), s([2, 5], [1, 4], [3, 6]), s([1, 2, 5], [4], [3, 6]), s([2, 5], [4], [1, 3, 6]), s([5], [2, 4], [1, 3, 6]), s([1, 5], [2, 4], [3, 6]), s([5], [1, 2, 4], [3, 6]), s([3, 5], [1, 2, 4], [6]), s([1, 3, 5], [2, 4], [6]), s([3, 5], [2, 4], [1, 6]), s([2, 3, 5], [4], [1, 6]), s([1, 2, 3, 5], [4], [6]), s([2, 3, 5], [1, 4], [6]), s([3, 5], [1, 4], [2, 6]), s([1, 3, 5], [4], [2, 6]), s([3, 5], [4], [1, 2, 6]), s([5], [3, 4], [1, 2, 6]), s([1, 5], [3, 4], [2, 6]), s([5], [1, 3, 4], [2, 6]), s([2, 5], [1, 3, 4], [6]), s([1, 2, 5], [3, 4], [6]), s([2, 5], [3, 4], [1, 6]), s([5], [2, 3, 4], [1, 6]), s([1, 5], [2, 3, 4], [6]), s([5], [1, 2, 3, 4], [6]), s([], [1, 2, 3, 4], [5, 6]), s([1], [2, 3, 4], [5, 6]), s([], [2, 3, 4], [1, 5, 6]), s([2], [3, 4], [1, 5, 6]), s([1, 2], [3, 4], [5, 6]), s([2], [1, 3, 4], [5, 6]), s([], [1, 3, 4], [2, 5, 6]), s([1], [3, 4], [2, 5, 6]), s([], [3, 4], [1, 2, 5, 6]), s([3], [4], [1, 2, 5, 6]), s([1, 3], [4], [2, 5, 6]), s([3], [1, 4], [2, 5, 6]), s([2, 3], [1, 4], [5, 6]), s([1, 2, 3], [4], [5, 6]), s([2, 3], [4], [1, 5, 6]), s([3], [2, 4], [1, 5, 6]), s([1, 3], [2, 4], [5, 6]), s([3], [1, 2, 4], [5, 6]), s([], [1, 2, 4], [3, 5, 6]), s([1], [2, 4], [3, 5, 6]), s([], [2, 4], [1, 3, 5, 6]), s([2], [4], [1, 3, 5, 6]), s([1, 2], [4], [3, 5, 6]), s([2], [1, 4], [3, 5, 6]), s([], [1, 4], [2, 3, 5, 6]), s([1], [4], [2, 3, 5, 6]), s([], [4], [1, 2, 3, 5, 6]), s([4], [], [1, 2, 3, 5, 6]), s([1, 4], [], [2, 3, 5, 6]), s([4], [1], [2, 3, 5, 6]), s([2, 4], [1], [3, 5, 6]), s([1, 2, 4], [], [3, 5, 6]), s([2, 4], [], [1, 3, 5, 6]), s([4], [2], [1, 3, 5, 6]), s([1, 4], [2], [3, 5, 6]), s([4], [1, 2], [3, 5, 6]), s([3, 4], [1, 2], [5, 6]), s([1, 3, 4], [2], [5, 6]), s([3, 4], [2], [1, 5, 6]), s([2, 3, 4], [], [1, 5, 6]), s([1, 2, 3, 4], [], [5, 6]), s([2, 3, 4], [1], [5, 6]), s([3, 4], [1], [2, 5, 6]), s([1, 3, 4], [], [2, 5, 6]), s([3, 4], [], [1, 2, 5, 6]), s([4], [3], [1, 2, 5, 6]), s([1, 4], [3], [2, 5, 6]), s([4], [1, 3], [2, 5, 6]), s([2, 4], [1, 3], [5, 6]), s([1, 2, 4], [3], [5, 6]), s([2, 4], [3], [1, 5, 6]), s([4], [2, 3], [1, 5, 6]), s([1, 4], [2, 3], [5, 6]), s([4], [1, 2, 3], [5, 6]), s([], [1, 2, 3], [4, 5, 6]), s([1], [2, 3], [4, 5, 6]), s([], [2, 3], [1, 4, 5, 6]), s([2], [3], [1, 4, 5, 6]), s([1, 2], [3], [4, 5, 6]), s([2], [1, 3], [4, 5, 6]), s([], [1, 3], [2, 4, 5, 6]), s([1], [3], [2, 4, 5, 6]), s([], [3], [1, 2, 4, 5, 6]), s([3], [], [1, 2, 4, 5, 6]), s([1, 3], [], [2, 4, 5, 6]), s([3], [1], [2, 4, 5, 6]), s([2, 3], [1], [4, 5, 6]), s([1, 2, 3], [], [4, 5, 6]), s([2, 3], [], [1, 4, 5, 6]), s([3], [2], [1, 4, 5, 6]), s([1, 3], [2], [4, 5, 6]), s([3], [1, 2], [4, 5, 6]), s([], [1, 2], [3, 4, 5, 6]), s([1], [2], [3, 4, 5, 6]), s([], [2], [1, 3, 4, 5, 6]), s([2], [], [1, 3, 4, 5, 6]), s([1, 2], [], [3, 4, 5, 6]), s([2], [1], [3, 4, 5, 6]), s([], [1], [2, 3, 4, 5, 6]), s([1], [], [2, 3, 4, 5, 6]), s([], [], [1, 2, 3, 4, 5, 6])]
在 SWI-Prolog 中，需要点击 W 你问交互式 shell 到 print the full list。
我知道已经有涵盖此内容的示例程序，但我需要用 6 个光盘以特定方式完成汉诺塔的任务，但我遇到了麻烦。我目前拥有的代码如下：
s([],[],[]).
initial(s([1,2,3,4,5,6], [], [])).
goal(s([],[],[1,2,3,4,5,6])).
我还有 26 行代码来验证有效状态，但是我自己测试了该代码并且它有效，我遇到的问题是创建代码以将光盘从一个堆栈移动到另一个堆栈。下面是我尝试执行的示例查询示例：
changeState((s([A | B],[],[])), s([C], [D], [])) :- C is B, D is A.
?- changeState((s([1,2,3,4,5,6],[],[])), s([2,3,4,5,6], [1], [])).
所以这将是最开始的地方，所有 6 个盘子都在第一堆上，我想将最上面的盘子移到第二堆。本质上，我希望能够从列表中删除第一个元素，并将其添加到另一个列表中，无论它是否为空。
编辑：
得到我需要的上述工作，现在我只需要帮助修复遍历谓词。完整代码如下：
%Post A, Post B, Post C
s([],[],[]).
initial(s([1,2,3,4,5,6], [], [])).
goal(s([],[],[1,2,3,4,5,6])).
valid([], _).
valid([H|_], X) :-
X < H.
changeState((s([A|T1], T2, T3)), s(T1, [A|T2], T3)) :-
valid(T2, A).
changeState((s([A|T1], T2, T3)), s(T1, T2, [A|T3])) :-
valid(T3, A).
changeState(s(T1, [A|T2], [B|T3]), s(T1, T2, [A,B|T3])) :-
valid(A,B).
changeState(s([A|T1], T2, [B|T3]), s([B,A|T1], T2, T3)) :-
valid(B, A).
changeState(s(T1, [A|T2], [B|T3]), s(T1, [B,A|T2], T3)) :-
valid(B, A).
changeState(s([A|T1], [B|T2], T3), s(T1, [A,B|T2], T3)) :-
valid(A,B).
changeState(s([A|T1], [B|T2], T3), s([B,A|T1], T2, T3)) :-
valid(B,A).
changeState(s([A|T1], T2, [B|T3]), s(T1, T2, [A,B|T3])) :-
valid(A,B).
changeState(s(T1, [A|T2], T3), s(T1, T2, [A|T3])) :-
valid(T3, A).
changeState(s(T1, [A|T2], T3), s([A|T1], T2, T3)) :-
valid(T1, A).
changeState(s(T1, T2, [A|T3]), s(T1, [A|T2], T3)) :-
valid(T2, A).
changeState(s(T1, T2, [A|T3]), s([A|T1], T2, T3)) :-
valid(T1, A).
traverse(StartNode,Sol,_) :- goal(StartNode), Sol = [StartNode].
traverse(StartNode,Sol,Visit) :- changeState(StartNode, NextNode),
not(member(NextNode, Visit)),
traverse(NextNode, PartialSol, [NextNode|Visit]),
Sol = [StartNode | PartialSol].
当我运行这个查询时：
?- traverse((s([1,2,3,4,5,6], [], [])), Sol, s([1,2,3,4,5,6], [], [])).
我得到这个输出：
在我收到这些回复大约 10 分钟后，我已经离开了它 运行ning，但它仍然没有产生新的回复，所以它只是继续 运行 一遍又一遍。如上所述，该程序的重点是使用列表解决具有 6 个圆盘的汉诺塔问题。对于那些不熟悉河内塔的人，您基本上需要将所有圆盘从第一叠移动到最后的第三叠。您一次只能移动 1 个圆盘，并且不能将较大的圆盘放在较小的圆盘之上。因此，您从 (s([1,2,3,4,5,6], [], [])) 开始，每个列表分别代表 Stack A、Stack B、Stack C，目标是以 ( s([], [], [1,2,3,4,5,6]))。我通过 changeState 谓词手动 运行 完成整个解决方案（63 次移动），并且所有 t运行sitions 都被接受，所以问题出在 t运行sverse 谓词上。 t运行sverse 谓词旨在显示导致解决方案的所有步骤以及所有可能的解决方案。它还意味着停止循环，因此它不仅仅是一遍又一遍地交换相同的 2 个光盘。不能完全弄清楚我的谓词有什么问题导致我得到这个输出，我对序言还是很陌生，所以我很感激任何帮助！
您可以在此处使用 统一 而不是 is/2（通常用于计算表达式）。
例如，假设第二座塔是空的，我们可以定义从第一座塔到第二座塔的移动：
changeState((s([A|T1],[], T3)), s(T1, [A], T3)).
或者我们可以将一个元素移动到非空的第二个塔，假设堆栈的顶部是一个更大的元素：
changeState(s([A|T1], [B|T2], T3), s(T1, [A,B|T2], T3)) :-
A < B.
以上将产生总共 12 条规则：3 个来源，乘以 2 个目的地，乘以 2 种可能性（空目的地与非空目的地）。这不是很优雅。我们可以构造一个辅助谓词来检查目标堆栈是否有效，其中：
valid_stack([], _).
valid_stack([H|_], X) :-
X < H.
那么我们可以将上面的两条规则压缩成：
changeState((s([A|T1], T2, T3)), s(T1, [A|T2], T3)) :-
valid_stack(T2, A).
因此，这将产生六个规则：三个来源和两个目的地。
因此我们不再需要验证移动，因为如果 changeState 成功，那么建议的移动是可能的 给定 原始状态是有效的。
但这不是完整的解决方案（我将其余部分作为练习）。您将需要一种机制来枚举可能的移动，并确保您不会陷入循环（例如在两座塔之间不断移动圆盘）。
使用 traverse/3 谓词后，我们获得了目标移动列表：
?- traverse(s([1,2,3,4,5,6], [], []), S, [s([1,2,3,4,5,6], [], [])]).
S = [s([1, 2, 3, 4, 5, 6], [], []), s([2, 3, 4, 5, 6], [1], []), s([3, 4, 5, 6], [1], [2]), s([1, 3, 4, 5|...], [], [2]), s([3, 4, 5|...], [], [1, 2]), s([4, 5|...], [3], [1, 2]), s([1|...], [3], [2]), s([...|...], [...|...], [...]), s(..., ..., ...)|...] [write]
S = [s([1, 2, 3, 4, 5, 6], [], []), s([2, 3, 4, 5, 6], [1], []), s([3, 4, 5, 6], [1], [2]), s([1, 3, 4, 5, 6], [], [2]), s([3, 4, 5, 6], [], [1, 2]), s([4, 5, 6], [3], [1, 2]), s([1, 4, 5, 6], [3], [2]), s([4, 5, 6], [1, 3], [2]), s([2, 4, 5, 6], [1, 3], []), s([1, 2, 4, 5, 6], [3], []), s([2, 4, 5, 6], [3], [1]), s([4, 5, 6], [2, 3], [1]), s([1, 4, 5, 6], [2, 3], []), s([4, 5, 6], [1, 2, 3], []), s([5, 6], [1, 2, 3], [4]), s([1, 5, 6], [2, 3], [4]), s([5, 6], [2, 3], [1, 4]), s([2, 5, 6], [3], [1, 4]), s([1, 2, 5, 6], [3], [4]), s([2, 5, 6], [1, 3], [4]), s([5, 6], [1, 3], [2, 4]), s([1, 5, 6], [3], [2, 4]), s([5, 6], [3], [1, 2, 4]), s([3, 5, 6], [], [1, 2, 4]), s([1, 3, 5, 6], [], [2, 4]), s([3, 5, 6], [1], [2, 4]), s([2, 3, 5, 6], [1], [4]), s([1, 2, 3, 5, 6], [], [4]), s([2, 3, 5, 6], [], [1, 4]), s([3, 5, 6], [2], [1, 4]), s([1, 3, 5, 6], [2], [4]), s([3, 5, 6], [1, 2], [4]), s([5, 6], [1, 2], [3, 4]), s([1, 5, 6], [2], [3, 4]), s([5, 6], [2], [1, 3, 4]), s([2, 5, 6], [], [1, 3, 4]), s([1, 2, 5, 6], [], [3, 4]), s([2, 5, 6], [1], [3, 4]), s([5, 6], [1], [2, 3, 4]), s([1, 5, 6], [], [2, 3, 4]), s([5, 6], [], [1, 2, 3, 4]), s([6], [5], [1, 2, 3, 4]), s([1, 6], [5], [2, 3, 4]), s([6], [1, 5], [2, 3, 4]), s([2, 6], [1, 5], [3, 4]), s([1, 2, 6], [5], [3, 4]), s([2, 6], [5], [1, 3, 4]), s([6], [2, 5], [1, 3, 4]), s([1, 6], [2, 5], [3, 4]), s([6], [1, 2, 5], [3, 4]), s([3, 6], [1, 2, 5], [4]), s([1, 3, 6], [2, 5], [4]), s([3, 6], [2, 5], [1, 4]), s([2, 3, 6], [5], [1, 4]), s([1, 2, 3, 6], [5], [4]), s([2, 3, 6], [1, 5], [4]), s([3, 6], [1, 5], [2, 4]), s([1, 3, 6], [5], [2, 4]), s([3, 6], [5], [1, 2, 4]), s([6], [3, 5], [1, 2, 4]), s([1, 6], [3, 5], [2, 4]), s([6], [1, 3, 5], [2, 4]), s([2, 6], [1, 3, 5], [4]), s([1, 2, 6], [3, 5], [4]), s([2, 6], [3, 5], [1, 4]), s([6], [2, 3, 5], [1, 4]), s([1, 6], [2, 3, 5], [4]), s([6], [1, 2, 3, 5], [4]), s([4, 6], [1, 2, 3, 5], []), s([1, 4, 6], [2, 3, 5], []), s([4, 6], [2, 3, 5], [1]), s([2, 4, 6], [3, 5], [1]), s([1, 2, 4, 6], [3, 5], []), s([2, 4, 6], [1, 3, 5], []), s([4, 6], [1, 3, 5], [2]), s([1, 4, 6], [3, 5], [2]), s([4, 6], [3, 5], [1, 2]), s([3, 4, 6], [5], [1, 2]), s([1, 3, 4, 6], [5], [2]), s([3, 4, 6], [1, 5], [2]), s([2, 3, 4, 6], [1, 5], []), s([1, 2, 3, 4, 6], [5], []), s([2, 3, 4, 6], [5], [1]), s([3, 4, 6], [2, 5], [1]), s([1, 3, 4, 6], [2, 5], []), s([3, 4, 6], [1, 2, 5], []), s([4, 6], [1, 2, 5], [3]), s([1, 4, 6], [2, 5], [3]), s([4, 6], [2, 5], [1, 3]), s([2, 4, 6], [5], [1, 3]), s([1, 2, 4, 6], [5], [3]), s([2, 4, 6], [1, 5], [3]), s([4, 6], [1, 5], [2, 3]), s([1, 4, 6], [5], [2, 3]), s([4, 6], [5], [1, 2, 3]), s([6], [4, 5], [1, 2, 3]), s([1, 6], [4, 5], [2, 3]), s([6], [1, 4, 5], [2, 3]), s([2, 6], [1, 4, 5], [3]), s([1, 2, 6], [4, 5], [3]), s([2, 6], [4, 5], [1, 3]), s([6], [2, 4, 5], [1, 3]), s([1, 6], [2, 4, 5], [3]), s([6], [1, 2, 4, 5], [3]), s([3, 6], [1, 2, 4, 5], []), s([1, 3, 6], [2, 4, 5], []), s([3, 6], [2, 4, 5], [1]), s([2, 3, 6], [4, 5], [1]), s([1, 2, 3, 6], [4, 5], []), s([2, 3, 6], [1, 4, 5], []), s([3, 6], [1, 4, 5], [2]), s([1, 3, 6], [4, 5], [2]), s([3, 6], [4, 5], [1, 2]), s([6], [3, 4, 5], [1, 2]), s([1, 6], [3, 4, 5], [2]), s([6], [1, 3, 4, 5], [2]), s([2, 6], [1, 3, 4, 5], []), s([1, 2, 6], [3, 4, 5], []), s([2, 6], [3, 4, 5], [1]), s([6], [2, 3, 4, 5], [1]), s([1, 6], [2, 3, 4, 5], []), s([6], [1, 2, 3, 4, 5], []), s([], [1, 2, 3, 4, 5], [6]), s([1], [2, 3, 4, 5], [6]), s([], [2, 3, 4, 5], [1, 6]), s([2], [3, 4, 5], [1, 6]), s([1, 2], [3, 4, 5], [6]), s([2], [1, 3, 4, 5], [6]), s([], [1, 3, 4, 5], [2, 6]), s([1], [3, 4, 5], [2, 6]), s([], [3, 4, 5], [1, 2, 6]), s([3], [4, 5], [1, 2, 6]), s([1, 3], [4, 5], [2, 6]), s([3], [1, 4, 5], [2, 6]), s([2, 3], [1, 4, 5], [6]), s([1, 2, 3], [4, 5], [6]), s([2, 3], [4, 5], [1, 6]), s([3], [2, 4, 5], [1, 6]), s([1, 3], [2, 4, 5], [6]), s([3], [1, 2, 4, 5], [6]), s([], [1, 2, 4, 5], [3, 6]), s([1], [2, 4, 5], [3, 6]), s([], [2, 4, 5], [1, 3, 6]), s([2], [4, 5], [1, 3, 6]), s([1, 2], [4, 5], [3, 6]), s([2], [1, 4, 5], [3, 6]), s([], [1, 4, 5], [2, 3, 6]), s([1], [4, 5], [2, 3, 6]), s([], [4, 5], [1, 2, 3, 6]), s([4], [5], [1, 2, 3, 6]), s([1, 4], [5], [2, 3, 6]), s([4], [1, 5], [2, 3, 6]), s([2, 4], [1, 5], [3, 6]), s([1, 2, 4], [5], [3, 6]), s([2, 4], [5], [1, 3, 6]), s([4], [2, 5], [1, 3, 6]), s([1, 4], [2, 5], [3, 6]), s([4], [1, 2, 5], [3, 6]), s([3, 4], [1, 2, 5], [6]), s([1, 3, 4], [2, 5], [6]), s([3, 4], [2, 5], [1, 6]), s([2, 3, 4], [5], [1, 6]), s([1, 2, 3, 4], [5], [6]), s([2, 3, 4], [1, 5], [6]), s([3, 4], [1, 5], [2, 6]), s([1, 3, 4], [5], [2, 6]), s([3, 4], [5], [1, 2, 6]), s([4], [3, 5], [1, 2, 6]), s([1, 4], [3, 5], [2, 6]), s([4], [1, 3, 5], [2, 6]), s([2, 4], [1, 3, 5], [6]), s([1, 2, 4], [3, 5], [6]), s([2, 4], [3, 5], [1, 6]), s([4], [2, 3, 5], [1, 6]), s([1, 4], [2, 3, 5], [6]), s([4], [1, 2, 3, 5], [6]), s([], [1, 2, 3, 5], [4, 6]), s([1], [2, 3, 5], [4, 6]), s([], [2, 3, 5], [1, 4, 6]), s([2], [3, 5], [1, 4, 6]), s([1, 2], [3, 5], [4, 6]), s([2], [1, 3, 5], [4, 6]), s([], [1, 3, 5], [2, 4, 6]), s([1], [3, 5], [2, 4, 6]), s([], [3, 5], [1, 2, 4, 6]), s([3], [5], [1, 2, 4, 6]), s([1, 3], [5], [2, 4, 6]), s([3], [1, 5], [2, 4, 6]), s([2, 3], [1, 5], [4, 6]), s([1, 2, 3], [5], [4, 6]), s([2, 3], [5], [1, 4, 6]), s([3], [2, 5], [1, 4, 6]), s([1, 3], [2, 5], [4, 6]), s([3], [1, 2, 5], [4, 6]), s([], [1, 2, 5], [3, 4, 6]), s([1], [2, 5], [3, 4, 6]), s([], [2, 5], [1, 3, 4, 6]), s([2], [5], [1, 3, 4, 6]), s([1, 2], [5], [3, 4, 6]), s([2], [1, 5], [3, 4, 6]), s([], [1, 5], [2, 3, 4, 6]), s([1], [5], [2, 3, 4, 6]), s([], [5], [1, 2, 3, 4, 6]), s([5], [], [1, 2, 3, 4, 6]), s([1, 5], [], [2, 3, 4, 6]), s([5], [1], [2, 3, 4, 6]), s([2, 5], [1], [3, 4, 6]), s([1, 2, 5], [], [3, 4, 6]), s([2, 5], [], [1, 3, 4, 6]), s([5], [2], [1, 3, 4, 6]), s([1, 5], [2], [3, 4, 6]), s([5], [1, 2], [3, 4, 6]), s([3, 5], [1, 2], [4, 6]), s([1, 3, 5], [2], [4, 6]), s([3, 5], [2], [1, 4, 6]), s([2, 3, 5], [], [1, 4, 6]), s([1, 2, 3, 5], [], [4, 6]), s([2, 3, 5], [1], [4, 6]), s([3, 5], [1], [2, 4, 6]), s([1, 3, 5], [], [2, 4, 6]), s([3, 5], [], [1, 2, 4, 6]), s([5], [3], [1, 2, 4, 6]), s([1, 5], [3], [2, 4, 6]), s([5], [1, 3], [2, 4, 6]), s([2, 5], [1, 3], [4, 6]), s([1, 2, 5], [3], [4, 6]), s([2, 5], [3], [1, 4, 6]), s([5], [2, 3], [1, 4, 6]), s([1, 5], [2, 3], [4, 6]), s([5], [1, 2, 3], [4, 6]), s([4, 5], [1, 2, 3], [6]), s([1, 4, 5], [2, 3], [6]), s([4, 5], [2, 3], [1, 6]), s([2, 4, 5], [3], [1, 6]), s([1, 2, 4, 5], [3], [6]), s([2, 4, 5], [1, 3], [6]), s([4, 5], [1, 3], [2, 6]), s([1, 4, 5], [3], [2, 6]), s([4, 5], [3], [1, 2, 6]), s([3, 4, 5], [], [1, 2, 6]), s([1, 3, 4, 5], [], [2, 6]), s([3, 4, 5], [1], [2, 6]), s([2, 3, 4, 5], [1], [6]), s([1, 2, 3, 4, 5], [], [6]), s([2, 3, 4, 5], [], [1, 6]), s([3, 4, 5], [2], [1, 6]), s([1, 3, 4, 5], [2], [6]), s([3, 4, 5], [1, 2], [6]), s([4, 5], [1, 2], [3, 6]), s([1, 4, 5], [2], [3, 6]), s([4, 5], [2], [1, 3, 6]), s([2, 4, 5], [], [1, 3, 6]), s([1, 2, 4, 5], [], [3, 6]), s([2, 4, 5], [1], [3, 6]), s([4, 5], [1], [2, 3, 6]), s([1, 4, 5], [], [2, 3, 6]), s([4, 5], [], [1, 2, 3, 6]), s([5], [4], [1, 2, 3, 6]), s([1, 5], [4], [2, 3, 6]), s([5], [1, 4], [2, 3, 6]), s([2, 5], [1, 4], [3, 6]), s([1, 2, 5], [4], [3, 6]), s([2, 5], [4], [1, 3, 6]), s([5], [2, 4], [1, 3, 6]), s([1, 5], [2, 4], [3, 6]), s([5], [1, 2, 4], [3, 6]), s([3, 5], [1, 2, 4], [6]), s([1, 3, 5], [2, 4], [6]), s([3, 5], [2, 4], [1, 6]), s([2, 3, 5], [4], [1, 6]), s([1, 2, 3, 5], [4], [6]), s([2, 3, 5], [1, 4], [6]), s([3, 5], [1, 4], [2, 6]), s([1, 3, 5], [4], [2, 6]), s([3, 5], [4], [1, 2, 6]), s([5], [3, 4], [1, 2, 6]), s([1, 5], [3, 4], [2, 6]), s([5], [1, 3, 4], [2, 6]), s([2, 5], [1, 3, 4], [6]), s([1, 2, 5], [3, 4], [6]), s([2, 5], [3, 4], [1, 6]), s([5], [2, 3, 4], [1, 6]), s([1, 5], [2, 3, 4], [6]), s([5], [1, 2, 3, 4], [6]), s([], [1, 2, 3, 4], [5, 6]), s([1], [2, 3, 4], [5, 6]), s([], [2, 3, 4], [1, 5, 6]), s([2], [3, 4], [1, 5, 6]), s([1, 2], [3, 4], [5, 6]), s([2], [1, 3, 4], [5, 6]), s([], [1, 3, 4], [2, 5, 6]), s([1], [3, 4], [2, 5, 6]), s([], [3, 4], [1, 2, 5, 6]), s([3], [4], [1, 2, 5, 6]), s([1, 3], [4], [2, 5, 6]), s([3], [1, 4], [2, 5, 6]), s([2, 3], [1, 4], [5, 6]), s([1, 2, 3], [4], [5, 6]), s([2, 3], [4], [1, 5, 6]), s([3], [2, 4], [1, 5, 6]), s([1, 3], [2, 4], [5, 6]), s([3], [1, 2, 4], [5, 6]), s([], [1, 2, 4], [3, 5, 6]), s([1], [2, 4], [3, 5, 6]), s([], [2, 4], [1, 3, 5, 6]), s([2], [4], [1, 3, 5, 6]), s([1, 2], [4], [3, 5, 6]), s([2], [1, 4], [3, 5, 6]), s([], [1, 4], [2, 3, 5, 6]), s([1], [4], [2, 3, 5, 6]), s([], [4], [1, 2, 3, 5, 6]), s([4], [], [1, 2, 3, 5, 6]), s([1, 4], [], [2, 3, 5, 6]), s([4], [1], [2, 3, 5, 6]), s([2, 4], [1], [3, 5, 6]), s([1, 2, 4], [], [3, 5, 6]), s([2, 4], [], [1, 3, 5, 6]), s([4], [2], [1, 3, 5, 6]), s([1, 4], [2], [3, 5, 6]), s([4], [1, 2], [3, 5, 6]), s([3, 4], [1, 2], [5, 6]), s([1, 3, 4], [2], [5, 6]), s([3, 4], [2], [1, 5, 6]), s([2, 3, 4], [], [1, 5, 6]), s([1, 2, 3, 4], [], [5, 6]), s([2, 3, 4], [1], [5, 6]), s([3, 4], [1], [2, 5, 6]), s([1, 3, 4], [], [2, 5, 6]), s([3, 4], [], [1, 2, 5, 6]), s([4], [3], [1, 2, 5, 6]), s([1, 4], [3], [2, 5, 6]), s([4], [1, 3], [2, 5, 6]), s([2, 4], [1, 3], [5, 6]), s([1, 2, 4], [3], [5, 6]), s([2, 4], [3], [1, 5, 6]), s([4], [2, 3], [1, 5, 6]), s([1, 4], [2, 3], [5, 6]), s([4], [1, 2, 3], [5, 6]), s([], [1, 2, 3], [4, 5, 6]), s([1], [2, 3], [4, 5, 6]), s([], [2, 3], [1, 4, 5, 6]), s([2], [3], [1, 4, 5, 6]), s([1, 2], [3], [4, 5, 6]), s([2], [1, 3], [4, 5, 6]), s([], [1, 3], [2, 4, 5, 6]), s([1], [3], [2, 4, 5, 6]), s([], [3], [1, 2, 4, 5, 6]), s([3], [], [1, 2, 4, 5, 6]), s([1, 3], [], [2, 4, 5, 6]), s([3], [1], [2, 4, 5, 6]), s([2, 3], [1], [4, 5, 6]), s([1, 2, 3], [], [4, 5, 6]), s([2, 3], [], [1, 4, 5, 6]), s([3], [2], [1, 4, 5, 6]), s([1, 3], [2], [4, 5, 6]), s([3], [1, 2], [4, 5, 6]), s([], [1, 2], [3, 4, 5, 6]), s([1], [2], [3, 4, 5, 6]), s([], [2], [1, 3, 4, 5, 6]), s([2], [], [1, 3, 4, 5, 6]), s([1, 2], [], [3, 4, 5, 6]), s([2], [1], [3, 4, 5, 6]), s([], [1], [2, 3, 4, 5, 6]), s([1], [], [2, 3, 4, 5, 6]), s([], [], [1, 2, 3, 4, 5, 6])]
在 SWI-Prolog 中，需要点击 W 你问交互式 shell 到 print the full list。