剑指offer栈的压入、弹出序列python

# -*- coding:utf-8 -*-
class Solution:
    def IsPopOrder(self, pushV, popV):
        # write code here
        stack = []
        i = 0
        l = len(popV)
        while i < l:
            if stack:
                if stack[-1] == popV[i]:
                    stack.pop() 
                    i+= 1
            if pushV:
                stack.append(pushV.pop(0))
            if stack:
                if (not pushV) and stack[-1] != popV[i]:
                    return False
        return True