栈的压入、弹出序列

# -*- coding:utf-8 -*-
class Solution:
    def IsPopOrder(self, pushV, popV):
        # write code here
        if len(pushV)!=len(popV):
            return False
        if pushV==None and popV==None:
            return True
        stack=[]
        j=0
        for i in range(0,len(popV)):
            if len(stack)>0:
                if stack[-1]==popV[i]:
                    stack.pop()
                    continue
            
            
            while (j<len(pushV)):
                stack.append(pushV[j])
                if pushV[j]==popV[i]:
                    stack.pop()
                    j+=1
                    break
                j+=1
        
        if len(stack)>0:
            return False
        else:
            return True