题目 用栈实现队列 正如标题所述,你需要使用两个栈来实现队列的一些操作. 队列应支持push(element),pop() 和 top(),其中pop是弹出队列中的第一个(最前面的)元素. pop和top方法都应该返回第一个元素的值. 样例 比如push(1), pop(), push(2), push(3), top(), pop(),你应该返回1,2和2 挑战 仅使用两个栈来实现它,不使用任何其他数据结构,push,pop 和 top的复杂度都应该是均摊O(1)的 解题 两个栈stack1…

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, 加时从第一个加, 取时从第二个取. public class Queue { private Stack<In…

Implement Queue by Two Stacks 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…

Implement Queue by Stacks 原题链接 : http://lintcode.com/zh-cn/problem/implement-queue-by-stacks/# 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…

3.5 Implement a MyQueue class which implements a queue using two stacks. LeetCode上的原题,请参见我之前的博客Implement Queue using Stacks 用栈来实现队列.…

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. Both pop and top methods should return the va…

比较典型的一个题目,easy,不过可以有许多实现方式. 这里用的方式是每次pop完成之后再将stack2中的内容立即倒回stack1中.但是其他的实现也可以不是这样,可以是需要push的时候检查再,如果内容在stack2中,这时候将其倒回在进行push.这里采取第一种比较笨的方法,代码如下所示: class Queue { public: // Push element x to the back of queue. void push(int x) { s1.push(x); } // Rem…

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. Both pop and top methods should return the va…

 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. Notes:…

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. Notes: You…