Python实现的序列化和反序列化二叉树算法示例

本文实例讲述了python/' target='_blank'>python实现的序列化和反序列化二叉树算法。分享给大家供大家参考，具体如下：

题目描述

请实现两个函数，分别用来序列化和反序列化二叉树

序列化二叉树

先序遍历二叉树

  def recursionSerialize(self, root):    series = ''    if root == None:      series += ',$'    else:      series += (',' + str(root.val))      series += self.recursionSerialize(root.left)      series += self.recursionSerialize(root.right)    return series  def Serialize(self, root):    return self.recursionSerialize(root)[1:]

结果：

root = TreeNode(11)root.left = TreeNode(2)root.right = TreeNode(3)series = Solution().Serialize(root)print(series)>>>11,2,$,$,3,$,$

反序列化

先构建根节点，然后左节点，右节点，同样是递归

注意由于使用的是字符串的表示形式，可以先转化为list，

print(series.split(','))>>>['11', '2', '$', '$', '3', '$', '$']

然后再处理就不需要将大于10的数字转换过来了：

  def getValue(self, s, sIndex):  #处理超过10的数字，将数字字符转变为数字    val = 0    while ord(s[sIndex]) <= ord('9') and ord(s[sIndex]) >= ord('0'):      val = val * 10 + int(s[sIndex])      sIndex += 1    return val, sIndex - 1

下面是反序列化的递归函数：

  def Deserialize(self, s):    if self.sIndex < len(s):      if s[self.sIndex] == ',':        self.sIndex += 1      if s[self.sIndex] == '$':        return None      val, self.sIndex = self.getValue(s, self.sIndex)      treeNode = TreeNode(val)      self.sIndex += 1      treeNode.left = self.Deserialize(s)      self.sIndex += 1      treeNode.right = self.Deserialize(s)      return treeNode

完整解法

class TreeNode:  def __init__(self, x):    self.val = x    self.left = None    self.right = Noneclass Solution:  def __init__(self):    self.sIndex = 0  def recursionSerialize(self, root):    series = ''    if root == None:      series += ',$'    else:      series += (',' + str(root.val))      series += self.recursionSerialize(root.left)      series += self.recursionSerialize(root.right)    return series  def Serialize(self, root):    return self.recursionSerialize(root)[1:]  def getValue(self, s, sIndex):  #处理超过10的数字，将数字字符转变为数字    val = 0    while ord(s[sIndex]) <= ord('9') and ord(s[sIndex]) >= ord('0'):      val = val * 10 + int(s[sIndex])      sIndex += 1    return val, sIndex - 1  def Deserialize(self, s):    if self.sIndex < len(s):      if s[self.sIndex] == ',':        self.sIndex += 1      if s[self.sIndex] == '$':        return None      val, self.sIndex = self.getValue(s, self.sIndex)      treeNode = TreeNode(val)      self.sIndex += 1      treeNode.left = self.Deserialize(s)      self.sIndex += 1      treeNode.right = self.Deserialize(s)      return treeNode

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