# DeFinition for a binary tree node.
# class TreeNode(object):
# def __init__(self,x):
# self.val = x
# self.left = None
# self.right = None
class Solution(object):
def postorderTraversal(self,root):
"""
:type root: TreeNode
:rtype: List[int]
"""
res = []
self.order(root,res)
return res
def order(self,root,res):
if root:
self.order(root.left,res)
self.order(root.right,res) res.append(root.val)
