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 {private...
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,...
1. 232 Implement Queue using Stacks 1.1 问题描写叙述 使用栈模拟实现队列。模拟实现例如以下操作: push(x). 将元素x放入队尾。 pop(). 移除队首元素。 peek(). 获取队首元素。 empty(). 推断队列是否为空。 注意:仅仅能使用栈的标准操作,push,pop,size和empty函数。 1.2 方法与思路 本题和用队列实现...
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...
我的LeetCode代码仓:https://github.com/617076674/LeetCode原题链接:https://leetcode-cn.com/problems/implement-queue-using-stacks/description/ 题目描述: 知识点:栈、队列 思路:双栈实现队列 push(x)和empty()的时间复杂度是O(1)。 pop()和peek()的 ...
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....
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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. ...
Two Stacks in a Single Array In this case, we need to define two stacks which are using same array. This method can be very useful from space optimization point of view in the software as this method has a potential to provide better memory utilization. Here we are going to look into ...