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
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. 1classMyQueue {23privateStack<Integer>s...
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...
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 value of first element. 正如标题所...
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。
AQueueimplements First In First Out while aStackis First In Last Out. It is possible to implement a queue using two stacks. When an item is to be inserted into the queue, we always push it to the first stack, and when we pop one element from the queue, we implement as popping it ...
Implement Queue by Two Stacks As the title described, you should only use two stacks to implement a queue's actions. The queue should supportpush(element),pop()andtop()where pop is pop the first(a.k.a front) element in the queue....
40. Implement Queue by Two Stacks/225. Implement Stack using Queues 本题难度: Medium/Easy Topic: Data Structure - stack/queue Description 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 ...
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 ...
LintCode Implement Queue by Two Stacks 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。