Prolog -查找经过所有节点的图中节点之间的路径及其距离

% 定义图的边
edge(a, b, 2).
edge(b, c, 3).
edge(c, d, 4).
edge(d, e, 5).
edge(e, f, 6).

% 定义路径查询规则
path(X, Y, Distance) :- edge(X, Y, Distance).
path(X, Y, Distance) :- edge(X, Z, D1), path(Z, Y, D2), Distance is D1 + D2.

% 查询经过所有节点的路径及其距离
find_path(AllNodes, Path, Distance) :-
    findall(D, (permutation(AllNodes, Nodes), path_sequence(Nodes, D)), Distances),
    min_list(Distances, Distance),
    path_sequence(Path, Distance).

% 查询路径序列
path_sequence([X, Y|Rest], Distance) :- path(X, Y, Distance1), path_sequence([Y|Rest], Distance2), Distance is Distance1 + Distance2.
path_sequence([_], 0).

% 示例查询
?- find_path([a, b, c, d, e, f], Path, Distance).