package Data_Structure;import java.util.NoSuchElementException;
import java.util.Random;//链队列，附设头结点
public class LinkQueue<T> {//内部结点类private static class Node<T>{T data;Node<T> next;public Node(T val){data=val;}public Node(){}public T getData() {return data;}public Node<T> getNext() {return next;}public void setNext(Node<T> next) {this.next = next;}}private final Node<T> head; //头指针private Node<T> tail; //尾指针private int size; //队列大小//初始化public LinkQueue(){head = tail = new Node<>(); //创建头结点，不存储具体数据//空队列为head和tail指向头结点}//入队public void enQueue(T val){Node<T> newNode = new Node<T>(val); //创建新结点tail.setNext(newNode); //指向新结点newNode.setNext(null); //队尾的next必为空tail = newNode; // 设置新队尾。size++;}//出队public T deQueue(){//处理队空if(head==tail){throw new NoSuchElementException("队列中没有元素");}T val = head.getNext().getData(); //获取队头元素head.setNext( head.getNext().getNext()); //出队//出队后，如果head.getNext为空，则代表队列中只有一个元素，则需更新尾指针if(head.getNext()==null){tail = head;}size--;return val;}// 查看队头元素（不移除）public T peek() {if (head==tail) {throw new NoSuchElementException("队列为空，无法获取队头元素");}return head.getNext().getData(); // 使用getter方法}//清空队列public void clear(){Node<T> p = head.getNext();while(p!=null){Node<T> temp = p.getNext();p.setNext(null);p=temp;}head.setNext(null);tail = head;size= 0;}// 查看队列元素public void show(){if(head==tail)throw new NoSuchElementException("队列为空");Node<T> current = head.getNext(); //获取首元结点while(current!=null){System.out.print(current.getData()+" ");current = current.getNext();}System.out.println();}public static void main(String[] args){LinkQueue<Integer> linkQueue =new LinkQueue<Integer>();for(int i=0;i<10;i++){Random ran = new Random();Integer val = ran.nextInt(999 - 100 + 1) + 100; //自动装箱linkQueue.enQueue(val);}linkQueue.show();System.out.println(linkQueue.peek());System.out.println("被出队的元素:"+linkQueue.deQueue());linkQueue.show();}}
