剑指Offer 07 重建二叉树

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。

 1 # -*- coding:utf-8 -*-
 2 # class TreeNode:
 3 #     def __init__(self, x):
 4 #         self.val = x
 5 #         self.left = None
 6 #         self.right = None
 7 class Solution:
 8     # 返回构造的TreeNode根节点
 9     def reConstructBinaryTree(self, pre, tin):
10         n = len(pre)
11         if n == 0:
12             return None
13         if n == 1:
14             return TreeNode(pre[0])
15         root = TreeNode(pre[0])
16         for i in range(len(tin)):
17             if tin[i] == pre[0]:
18                 break
19         root.left = self.reConstructBinaryTree(pre[1:i+1],tin[:i])
20         root.right = self.reConstructBinaryTree(pre[i+1:],tin[i+1:])
21         return root
22         # write code here