You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack). 题意及分析:用标准的queue实现stack。这里关键就是添加完成时,刚添加的点要在queue最前面,将queue的前面的点依次取出并添加到queue尾就可以实现这个stack添加功能。 代码: 1 2 3...
queue_1.add(x); top = x; }/** Removes the element on top of the stack and returns that element. */publicintpop(){if(empty()){thrownewRuntimeException("MyStack空了!"); }while(queue_1.size() >1){ top = queue_1.remove(); queue_2.add(top); }intlast_ele=queue_1.remove()...
import java.util.LinkedList; import java.util.Queue; class Solution { Queue[] queues; int cur; Solution() { queues = new LinkedList[2]; queues[0] = new LinkedList<Integer>(); queues[1] = new LinkedList<Integer>(); cur = 0; } // Push element x onto stack. public void push(int ...
while(!queue2.isEmpty()){ top = queue2.poll(); queue1.offer(top); } }else{ while(!queue1.isEmpty()){ top = queue1.poll(); queue2.offer(top); } } return top; } /** Returns whether the stack is empty. */ public boolean empty() { return queue1.isEmpty() && queue2.isE...
import java.util.ArrayList;import java.util.LinkedList;import java.util.Queue;classMyStack{privateQueue<Integer>q=newLinkedList<Integer>();// Push element x onto stack.publicvoidpush(intx){q.offer(x);}// Removes the element on top of the stack.publicvoidpop(){if(q.isEmpty())return;Array...
You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack). java中的LinkedList实现了Queue接口,可以直接使用。 queue提供了offer()方法和poll()方法,用于加入元素和删除队首元素。
importjava.util.LinkedList;importjava.util.Queue;classMyStack{privateQueue<Integer>queue_1=newLinkedList<>();privateQueue<Integer>queue_2=newLinkedList<>();privateint top;/** Initialize your data structure here. */publicMyStack(){}/** Push element x onto stack. */publicvoidpush(int x){queu...
import java.util.*;classMyStack{Queue<Integer>q1;Queue<Integer>q2;/** Initialize your data structure here. */publicMyStack(){q1=newLinkedList<Integer>();q2=newLinkedList<Integer>();}/** Push element x onto stack. */publicvoidpush(intx){q1.offer(x);}/** Removes the element on top ...
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 s = q.size(); q.push(val); for (int i=0...
思路:Queue是先进先出FIFO,Stack是先进后出FILO。使用Stack模拟实现Queue的功能,可以使用两个Stack,一个进行入Stack操作,一个进行出Stack操作。这两个Stack中的元素位置是颠倒的。比如,一个元素在第一个Stack位于Stack头,那么这个元素在另一个Stack则位于Stack尾。