# -*- coding:utf-8 -*-
class Solution:
def __init__(self):
self.stack1=[]
self.stack2=[]
def push(self, node):
# write code here
self.stack1.append(node)
def pop(self):
# return xx
if self.stack2!=[]:
return self.stack2.pop()
else:
while(self.stack1!=[]):
self.stack2.append(self.stack1.pop())
if self.stack2==[]:
return None
else:
return self.stack2.pop()
在python中,list.pop()弹出的是列表中最后一个元素,所以该操作与栈的方式相同