序言 - 检查元素是否是二叉树的成员

Question

如何检查元素是否在二叉树中？例如，

tree1(node(10,empty, node(100,empty, empty))). 
tree2(node(~, node(+, empty, node(*, empty, empty)), node(!, node(/,empty, empty),empty))). 
badTree(node(3, node(5, empty), empty)) . 

?- tree2(T), memberT(!,T). 
T = node(~, node(+, empty, node(*, empty, empty)), node(!, node(/, empty, empty), empty)) . 
?- tree1(T),memberT(100,T). 
T = node(10, empty, node(100, empty, empty)) . 

Answer 1

不知道如果这正是你的问题，但这里是产生你给（假设他们是为了成为一个规范）结果代码：

memberT(Val, node(Val, _Left, _Right)). 
memberT(Val, node(_Val1, Left, _Right)) :- memberT(Val, Left). 
memberT(Val, node(_Val1, _Left, Right)) :- memberT(Val, Right).