04重建二叉树.py

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


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


class Solution:
    # 返回构造的TreeNode根节点
    def reConstructBinaryTree(self, pre, tin):
        # write code here
        if not pre:
            return None
        res = TreeNode(pre[0])
        tin_index = tin.index(pre[0])
        res.left = self.reConstructBinaryTree(pre[1:tin_index+1], tin[:tin_index])
        res.right = self.reConstructBinaryTree(pre[tin_index+1:], tin[tin_index+1:])
        return res