Subsequent binary search tree traversal (python)

　　Title Description

Enter an integer array, the array is not the result of the determination after traversing a binary search tree. If the output Yes, otherwise the output No. Suppose the input array of any two numbers are different from each other.

This question is particularly silly place:

　　Return false empty when the input sequence, but to be recursive procedure returns true null

 1 # -*- coding:utf-8 -*-
 2 class Solution:
 3     def VerifySquenceOfBST(self, sequence):
 4         # write code here
 5         if sequence==[]:
 6             return False
 7         rootNum=sequence[-1]
 8         del sequence[-1]
 9         index=None
10         for i in range(len(sequence)):
11             if index == None and sequence[i]>rootNum:
12                 index = i
13             if index !=None and sequence[i]< rootNum:
14                 return False
15         if sequence[:index]==[]:
16             left = True
17         else:
18             left = self.VerifySquenceOfBST(sequence[:index])
19         if sequence[index:]==[]:
20             right = True
21         else:
22             right = self.VerifySquenceOfBST(sequence[index:])
23         return left and right

2019-12-12 08:56:33