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...
Implement Queue using 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 the queue is empty. Notes: You...
两个栈stack1 、stack2,一个存储入队列元素,一个存储出出队列元素 stack2 入队列 stack1出队列 当入队列的时候:直接在入栈stack2 当出队列的时候:若栈stack2中有元素,则栈stack2底的元素就是所要出队列的元素,将栈stack2中的元素全部出来,并放到栈stack1中,此处stack1栈顶元素就是答案 这里有个问题是若栈...
第二个方法类似,不同之处在于pop需要o(n), push o(1) classMyQueue:def__init__(self):self.s1=[]self.s2=[]defpush(self,x):self.s1.append(x)defpop(self):self.peek()returnself.s2.pop()defpeek(self):ifnotself.s2:whileself.s1:self.s2.append(self.s1.pop())returnself.s2[-1]defem...
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...
1 读题 LeetCode 232E 用栈实现队列 Implement Queue using Stacks 2 Python 解题 正如咱们前面那个问题,list 既可以实现栈,还能实现列表,所以咱这题的代码,和那个队列模拟栈的就很类似了。 ## LeetCode 232## Impletement Queue using StackclassMyQueue:def__init__(self):self.l1=[]## stack 1 = l1se...
In this tutorial, we’re going to implement a stack data structure using two queues. 2. Stack and Queue Basics Before proceeding to the algorithm, let’s first take a glance at these two data structures. 2.1. Stack In a stack, we add elements in LIFO (Last In, First Out) order.This...
232. Implement Queue using Stacks刷题笔记 用两个栈来实现队列操作 class MyQueue: def __init__(self): self.stack_in = [] self.stack_out = [] def push(self, x: int) -> None: self.stack_in.append(x) def pop(self) -> int:...
Implement the following operations of a queue using stacks. 使用两个栈实现一个队列。 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. ...
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...