# -*- coding: utf-8 -*-

class Solution:

def __init__(self):

self.ret = []

"""

@param root: The root of binary tree.

@return: Postorder in ArrayList which contains node values.

"""

def postorderTraversal(self, root):

# write your code here

if root is not None:

self.postorderTraversal(root.left) # 遍历左子树

self.postorderTraversal(root.right) # 遍历右子树

self.values.ret(root.val)

return self.values