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
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 ...
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. ...
A classic interview question.This linkhas a nice explanation of the idea using two stacks and its amortized time complexity. I use the same idea in my code, which is as follows. 1classQueue {2public:3//Push element x to the back of queue.4voidpush(intx) {5stack1.push(x);6}78//...
Depending on your language, the queue may not be supported natively. You may simulate a queue using a list or deque (double-ended queue) as long as you use only a queue's standard operations. Example 1: Input ["MyStack", "push", "push", "top", "pop", "empty"] ...
class MyQueue: def __init__(self): """ Initialize your data structure here. """ self.stack1 = [] self.stack2 = [] def push(self, x): """ Push element x to the back of queue. :type x: int :rtype: void """ self.stack1.append(x) ...
Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as long as you use only standard operations of a stack. You may assume that all operations are valid (for example, no pop or peek operations will be...
// Removes an element from the queue pop(st) Dequeue an element from the queue. C++ Java Python #include<bits/stdc++.h> using namespace std; class Stack { queue<int>q; public: void push(int val); void pop(); int top(); bool empty(); }; void Stack::push(int val) { int ...
/** Push element x to the back of queue. */publicvoidpush(intx) {s1.push(x); } So what if usingpeekto get the front element of the queue at this time? Logically speaking, the front element should be 1, but ins1, 1 is pushed to the bottom of the stack. Now ...
原题链接:https://leetcode.com/problems/implement-queue-using-stacks/ 这道题有个需要注意的地方是只能用stack的基本特性来实现队列,所以必须建立两个stack来实现push一个元素在队列里的操作。 第一个方法中pop只需要o(1), 而push需要o(n) classMyQueue(object):def__init__(self):""" ...