# -*- coding:utf-8 -*-

class Solution:

    def VerifySquenceOfBST(self, sequence):

        # write code here

        if not sequence or len(sequence)<=0:

            return False

        root=sequence[-1]

        i=0

        #找出左小右大的分界点i,此时i属于右子树

        for node in sequence[:-1]:

            if node > root:

                break

            i+=1

        #如果在右子树中有比根节点小的值，直接返回False

        for node in sequence[i:-1]:

            if node < root:

                return False

        #判断左子树是否为二叉搜索树

        left=True

        if i>0:

            left=self.VerifySquenceOfBST(sequence[:i])

        #判断右子树是否为二叉搜索树

        right=True

        if i<len(sequence)-1:

            right=self.VerifySquenceOfBST(sequence[i:-1])

　　　　 return left and right