剑指offer-序列化二叉树（python）

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def __init__(self):
        self.flag=-1
    def Serialize(self, root):
        # write code here
        if not root:
            return "#"
        return str(root.val)+','+self.Serialize(root.left)+','+self.Serialize(root.right)
    def Deserialize(self, s):
        # write code here
        self.flag += 1
         
        l = s.split(',')
        if self.flag >= len(s):
            return None
         
        root = None
        if l[self.flag] != '#':
            root = TreeNode(int(l[self.flag]))
            root.left = self.Deserialize(s)
            root.right = self.Deserialize(s)
        return root