python题解

class Solution:
    # 返回构造的TreeNode根节点
    def reConstructBinaryTree(self, pre, tin):
        # write code here
        if len(pre) == 1:
            head = TreeNode(pre[0])
            head.left = None
            head.right = None
            return head
        head = TreeNode(pre[0])      
        temp1 = tin.index(pre[0])
        length = len(tin[:temp1])
        if temp1 == 0:
            head.left = None
        else:
            head.left = self.reConstructBinaryTree(pre[1:length+1], tin[:temp1])
        if length + 1 < len(pre):
            head.right = self.reConstructBinaryTree(pre[length+1:], tin[temp1+1:])
        else:
            head.right = None
        return head