在BST Python中删除节点

class TreeNode:
    def __init__(self, key):
        self.left = None
        self.right = None
        self.val = key

def minValueNode(node):
    current = node
    while(current.left is not None):
        current = current.left
    return current

def deleteNode(root, key):
    if root is None:
        return root
    
    if key < root.val:
        root.left = deleteNode(root.left, key)
    elif(key > root.val):
        root.right = deleteNode(root.right, key)
    else:
        if root.left is None:
            temp = root.right
            root = None
            return temp
        elif root.right is None:
            temp = root.left
            root = None
            return temp
        
        temp = minValueNode(root.right)
        root.val = temp.val
        root.right = deleteNode(root.right, temp.val)
    return root