Question

如何使用深度优先搜索找到城市之间的可能路线这是我的代码：

DOMAINS
    s = symbol.
    sList = symbol*.

PREDICATES
    nondeterm link(s, s,integer).
    nondeterm depth_first_search(s, s, sList,integer).

CLAUSES


    link("Erbil","Koysinjaq",12).
    link("Erbil","Kirkuk",15).
    link("Erbil","Shaqlawa",15).
    link("Erbil","Mosul",22).
    link("Shaqlawa","Akre",33).
    link("Mosul","Duhok",44).
    link("Mosul","Akre",55).
    link("Kirkuk","Koysinjaq",66).
    link("Kirkuk","Chamchamal",88).
    link("Chamchamal","Sulaimani",34).
    link("Koysinjaq","Sulaimani",22).
    link("Sulaimani","Ranya",33).
    link("Akre","Duhok",22).

    depth_first_search(X, X, [X],0).
    depth_first_search(X, Y, [X|T],NewDis):-
        link(X, Z , Dis),
        NewDis=NewDis+Dis,
        depth_first_search(Z, Y, T,NewDis).

GOAL
    depth_first_search("Erbil", "Duhok", PathToGoal,Dis).

当我执行时我得到了这个错误：

E;Test_Goal, pos: 652, 707 Free variable in expression

在这里，我希望这些城市之间的所有可能的联系与它们之间的距离现在该怎么做，谢谢你的帮助

Answer 1

看这是你的错误：

depth_first_search(X, X, [X],0).
    depth_first_search(X, Y, [X|T],L):-
        link(X, Z , L1),
        depth_first_search(Z, Y, T,L2),L=L1+L2.

GOAL
    depth_first_search("Erbil", "Duhok", PathToGoal,Dis).

它现在为我工作：）

如何在Prolog中找到城市之间的距离？

1 个答案: