用两个栈实现队列

# -*- 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 len(self.stack2) == 0:
            while len(self.stack1) != 0:
                 self.stack2.append(self.stack1[len(self.stack1)-1])
                 self.stack1.pop()
        pop = self.stack2[len(self.stack2)-1]
        self.stack2.pop()
        return pop

写个python版本的，仅供参考，已运行成功。