stack1(in): is the only stack to store new elements when adding a new element into the queue stack2(out): is the only stack to pop old element out of the queue. when stack2 is empty, we move all data from stack1(in) to stack2(out) if any **/publicclassQueueUseStack {privateD...
LC.232. Implement Queue using Stacks(use two stacks) https://leetcode.com/problems/implement-queue-using-stacks/description/ Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue. pop() -- Removes the element from in front of queue. ...
1. stack(先进后出): pop 拿出并返回最后值; peek 返回最后值; push 加入新值在后面并返回此值。 2. queue(先进先出) : poll = remove 拿出并返第一个值; element = peek 返第一个值; add = offer 加入新值在后面并返回true/false。 做此题时, 第一个stack为基础, 第二个stack为媒介来颠倒顺序,...
Initialize your data structure here. """#why use two stack hereself.s1=[]self.s2=[]defpush(self,x):""" Push element x to the back of queue. :type x: int :rtype: None """#把s1中的内容挨个pop出去,每pop一个向s2中append一个#s1为空之后将新加进来的元素放到stack的最底部#再重复第...
Queue Stack It's finally here: >> The Road to Membership and Baeldung Pro. Going into ads,no-ads reading, and bit about how Baeldung works if you're curious :) 1. Introduction In this tutorial, we’re going to implement a stack data structure using two queues. ...
首先确定要有两个stack存数据, 我是设定一个stack 存有所有的数据, 基本上这个stack 就是个queue 。 再回来考虑queue和stack 的区别, 在queue中先进先出, stack 先进后出。 所以我觉得push的时候是没什么区别的 都是按某种顺序放进这个数据结构里面。 区别就在pop的时候对它进行了处理, 其实我的stackTwo可以不...
class QueueTwoStacks(object): # Implement the enqueue and dequeue methods def enqueue(self, item): pass def dequeue(self): pass # Tests class Test(unittest.TestCase): def test_basic_queue_operations(self): queue = QueueTwoStacks() queue.enqueue(1) queue.enqueue(2) queue.enqueue(3) actual...
Implement Queue using Stacks Problem: Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue. pop() -- Removes the element from in front of queue. peek() -- Get the front elemen......
Lintcode: Implement Queue by Stacks Lintcode As the title described, you should only use two stacks to implement a queue's actions.The queue should support push(element), pop() and top() where pop is pop the first(a.k.a front) element in the queue....
Implement the following operations of a queue using stacks. push(x) – Push element x to the back of queue. pop() – Removes the element from in front of queue. peek() – Get the front element. empty() – Return whether the queue is empty. ...