You may assume that all operations are valid (for example, no pop or peek operations will be called on an empty queue). 这道题让我们用栈来实现队列,之前我们做过一道相反的题目Implement Stack using Queues 用队列来实现栈,是用队列来实现栈。这道题颠倒了个顺序,起始并没有太大的区别,栈和队列的...
publicclassMyStack{ Queue<Integer> q;publicMyStack(){// int size():获取队列长度;//boolean add(E)/boolean offer(E):添加元素到队尾;//E remove()/E poll():获取队首元素并从队列中删除;//E element()/E peek():获取队首元素但并不从队列中删除。q =newLinkedList<>(); }publicvoidpush(in...
int pop()Removes the element on the top of the stack and returns it. int top()Returns the element on the top of the stack. boolean empty()Returnstrueif the stack is empty,falseotherwise. Notes: You must useonlystandard operations of a queue, which means that onlypush to back,peek/pop...
Depending on your language, queue may not be supported natively. You may simulate a queue by using a list or deque (double-ended queue), as long as you use only standard operations of a queue. You may assume that all operations are valid (for example, no pop or top operations will be...
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...
You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack). 要求使用双队列实现一个栈的所有的功能,是一个很经典的问题,需要记住学习。 建议和这道题leetcode 232. Implement Queue using Stacks 双栈实现队列 一起学习。
1 审题 LeetCode 225E 栈Stack:后进先出,last-in-first-out LIFO 队列Queue:先进先出,first-in-first-out FIFO 题目要求: 最多使用2个队列,来实现栈; 支持栈的方法: push(x), 把元素 x 推入栈; top/peek(), 返回栈顶元素; pop,移除栈顶元素; ...
(self):"""Initialize your data structure here."""# 声明两个队列,由于模拟栈self.queue1 = deque()self.queue2 = deque()# self._empty指向当前空的队列self._empty = self.queue1# self._filled指向当前有填充的队列self._filled = self.queue2def push(self, x):"""Push element x onto stack....
class Stack: # initialize your data structure here. def __init__(self): self.q_ = Queue() # @param x, an integer # @return nothing def push(self, x): self.q_.push(x) for _ in xrange(self.q_.size() - 1): self.q_.push(self.q_.pop()) # @return nothing ...
}// Return whether the stack is empty.boolempty(){returnq1.empty() && q2.empty(); }private: queue<int> q1; queue<int> q2;voidgather(queue<int>& q1, queue<int>& q2){while(!q2.empty()) { q1.push(q2.front()); q2.pop(); ...