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()