4.重建二叉树(python)

 1 class Solution:
 2     # 返回构造的TreeNode根节点
 3     def reConstructBinaryTree(self, pre, tin):
 4         # write code here
 5         if len(pre)==0:
 6             return None
 7         if len(pre) == 1:
 8             return TreeNode(pre[0])
 9         root = TreeNode(pre[0])
10         tinL = tin[0:tin.index(pre[0])]
11 
12         tinR = tin[tin.index(pre[0])+1:]
13         root.left = self.reConstructBinaryTree(pre[1:tin.index(pre[0])+1],tinL)
14         root.right = self.reConstructBinaryTree(pre[tin.index(pre[0])+1:],tinR)
15         return root