第五题

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time : 2020/5/24 下午4:47
# @Author : Yuxiaoxue# @Site : 
# @File : ques5.py
# @Software: PyCharm

'''
题目描述：
用两个栈来实现一个队列，完成队列的Push和Pop操作。 队列中的元素为int类型。
'''
stack1 = []
stack2 = []

def push(node):
    stack1.append(node)
def pop():
    if stack2 == []:
        while stack1:
            top = stack1.pop()
            stack2.append(top)
    if stack2 != []:
        print(stack2[-1])
        top = stack2[-1]
        stack2.pop()
        return top

push(1)
push(2)
push(3)
top = pop()
top = pop()
push(4)
top = pop()
push(5)
top = pop()
top = pop()



'''
牛客网最终提交答案;
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 == []:
            while self.stack1:
                top = self.stack1.pop()
                self.stack2.append(top)
        if self.stack2 != []:
            top = self.stack2[-1]
            self.stack2.pop()
            return top

'''