Approach #1 (Two Queues, push - O(1)O(1), pop O(n)O(n) ) Intuition Stack is LIFO (last in - first out) data structure, in which elements are added and removed from the same en... leetcode 676之Implement Magic Dictionary
【LeetCode题解】232_用栈实现队列(Implement-Queue-using-Stacks) 目录 描述 解法一:在一个栈中维持所有元素的出队顺序 思路 入队(push) 出队(pop) 查看队首(peek) 是否为空(empty) Java 实现 Python 实现 解法二:一个栈入,一个栈出 思路 入队(push) 出队(pop) 查看队首(peek) 是否为空(empty) ...
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...
时间复杂度:O(n)O(n),其中nn表示入队时队列元素的数目,即栈1中元素的数目。入队时,栈1中的元素需要进行出栈和入栈两次,需要4n4n次操作,再加上新的元素的一次入栈操作,总的操作次数为4n+14n+1次。由于栈的入栈和出栈的时间复杂度是O(1)O(1)的,因此,入队的时间复杂度是O(n)O(n)的 空间复杂度:O(...
peek:In computer science, peek is an operation on certain abstract data types, specifically sequential collections such as stacks and queues, which returns the value of thetop("front")of the collectionwithout removing the element from the collection. It thus returns the same value as operations ...
需要维护 push 栈和 pop 栈中共 O(n) 个元素 代码(Python3) class MyQueue: def __init__(self): # push 栈维护已放入的元素 self.push_stack: List[int] = [] # pop 栈维护待移除的元素。 #将 push 栈中的元素放入 pop 栈时,就将先进后出转换为了先进先出 self.pop_stack: List[int] = [...
232. Implement Queue using Stacks # 题目# 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...
shiftStack();if(!_old.empty())return_old.top();return0; }//Return whether the queue is empty.boolempty(void) {return_old.empty() &&_new.empty(); }private: stack<int>_old, _new; }; 用栈来实现队列[LeetCode] Implement Queue using Stacks,如需转载请自行联系原博主。
leetcode 232. 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....
LeetCode problem solving notes. Implement a first in first out (FIFO) queue using only two stacks. The implemented queue should support all the functions of a normal queue (push, peek, pop, and empty).