剑指offer_用两个栈实现队列（转载）

用两个栈实现队列

转载自：https://blog.csdn.net/fuxuemingzhu/article/details/79499461

# -*- coding:utf-8 -*-
class Solution:
    def __init__(self):
        self.stack1 = []
        self.stack2 = []

    def push(self, node):
        self.stack1.append(node)

    def pop(self):
        if self.stack2:
            return self.stack2.pop()
        else:
            while self.stack1:
                self.stack2.append(self.stack1.pop())
            return self.stack2.pop()