无法添加 BinarySubTree

Question

只有当节点连接到树的左分支或右分支时，它才能正常工作。但是当涉及到将节点附加到子树时，事实证明它没有成功添加。代码如下：

class BinaryTree():
    class BinaryTreeNode():
        def __init__(self,leftchildnode,rightchildnode,item):
            self.leftchildnode = leftchildnode
            self.rightchildnode = rightchildnode
            self.item = item

    def __init__(self):
        self.root = None
    
    def setRoot(self,item):
        self.cur = self.BinaryTreeNode(None,None,item)
        self.root = self.cur

    def attachLeft(self,item):
        self.left = self.BinaryTreeNode(self.root.leftchildnode,None,item)
        self.root.leftchildnode = self.left

    def attachRight(self,item):
        self.right = self.BinaryTreeNode(None,self.root.rightchildnode,item)
        self.root.rightchildnode = self.right

    def attachLeftSub(self,Binarytree):
        global BinaryTree
        self.root.leftchildnode = BinaryTree
        BinaryTree = None
    
    def attachRightSub(self,Binarytree):
        global BinaryTree
        self.root.rightchildnode = BinaryTree
        BinaryTree = None

    def inorderdisplay(self):
        self.recursive_inorder_display(self.root)

    def recursive_inorder_display(self,BinaryTreeNode):
        if BinaryTreeNode != None:
            self.recursive_inorder_display(BinaryTreeNode.leftchildnode)
            print(BinaryTreeNode.item)
            self.recursive_inorder_display(BinaryTreeNode.rightchildnode)

tree = BinaryTree()
tree.setRoot("J")
tree1 = BinaryTree()
tree1.setRoot("D")
tree1.attachLeft("E")
tree1.attachRight("F")
tree2 = BinaryTree()
tree2.setRoot("G")
tree2.attachLeft("H")
tree2.attachRight("I")
tree.attachLeftSub(tree1)
tree.attachLeftSub(tree2)
tree.inorderdisplay()

它应该按顺序显示所有项目，但 I 得到的唯一项目是 J。你能指出错误在哪里吗？

Answer 1

def attachRightSub(self,Binarytree):
    global BinaryTree
    self.root.rightchildnode = BinaryTree
    BinaryTree = None

应该是

def attachRightSub(self,BinaryTree):
    self.root.rightchildnode = BinaryTree.root

你正在做的是删除你原来的 BinaryTree 类。