# -*- coding:utf-8 -*-
__author__ = "leo"

# 输入某二叉树的前序遍历和中序遍历的结果，请重建出该二叉树。
# 假设输入的前序遍历和中序遍历的结果中都不含重复的数字。
# 例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6}，则重建二叉树并返回。


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


class Solution:
    def re_construct_binary_tree(self, pre, tin):
        if len(pre) == 0:
            return None

        root = TreeNode(pre[0])
        pos = tin.index(pre[0])
        root.left = self.re_construct_binary_tree(pre[1: 1+pos], tin[: pos])
        root.right = self.re_construct_binary_tree(pre[pos+1:], tin[pos+1:])
        return root
