java实现双向链表

package 数据结构.链表.双链表;

public class DoubleNode {
    private DoubleNode precursor;
    private int date;
    private DoubleNode next;

    public DoubleNode(int date) {
        this.date = date;
    }

    public DoubleNode(DoubleNode precursor, int date, DoubleNode next) {
        this.precursor = precursor;
        this.date = date;
        this.next = next;
    }

    public DoubleNode getPrecursor() {
        return precursor;
    }

    public int getDate() {
        return date;
    }

    public DoubleNode getNext() {
        return next;
    }

    public void setPrecursor(DoubleNode precursor) {
        this.precursor = precursor;
    }

    public void setDate(int date) {
        this.date = date;
    }

    public void setNext(DoubleNode next) {
        this.next = next;
    }

}

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package 数据结构.链表.双链表;

/**
 * Author : PingLu
 * TimeBegin : 2022/03/06
 * 双链表  实现增删改操作  CURD
 * DoneTime 2022/03/07
 */
public class DoubleLink {
    private DoubleNode head;
    int size = 0;

    public DoubleLink(){
        //默认构造一个带有头系结点的双链表
        head = new DoubleNode(null,0,null);
    }

    public DoubleNode getHead() {
        return head;
    }

    public void setHead(DoubleNode head) {
        this.head = head;
    }

    public int getSize() {
        return size;
    }

    //判断链表是否为空
    public boolean LinkIsEmpty(){
        return head.getNext() == null;
    }

    //遍历输出链表
    public void printDoubleLink(){
        DoubleNode pMove = head;
        System.out.println("当前链表为:"+head.getDate()+"\t大小为:"+this.size);
        while (pMove.getNext() != null){
            System.out.print(pMove.getNext().getDate()+"<-->");
            pMove = pMove.getNext();
        }
        System.out.println();
    }

    //增加结点  效率高
    public void addNode(DoubleNode node){
        //如果链表中只有头节点结点直接加到头结点之后,否认需要找到链表的最后一个元素加到最后一个元素的后面
        if(head.getNext() == null){
            head.setNext(node);
            node.setPrecursor(head);
            node.setNext(null);
            size ++;
            return;
        }
        DoubleNode pMove = head;
        while (pMove.getNext() != null){
            pMove = pMove.getNext();
        }
        pMove.setNext(node);
        node.setPrecursor(pMove);
        node.setNext(null);
        size ++;
    }

    //删除结点  效率高
    public void delNode(int date){
        if(LinkIsEmpty()){
            System.out.println("Link is Empty!");
            return;
        }
        if(!findNode(date)){
            return;
        }
        DoubleNode tempNode = head;
        while(tempNode.getDate() != date){
            tempNode = tempNode.getNext();
        }
        //删除操作
        DoubleNode f = tempNode.getPrecursor();
        DoubleNode t = tempNode.getNext();
        f.setNext(t);
        t.setPrecursor(f);
        size --;
        System.out.println("Delete Node"+date+"Successful!");
    }

    //查找结点
//    public void findNode(int date){
//        if(LinkIsEmpty()){
//            System.out.println("Link is Empty!");
//            return;
//        }
//        DoubleNode pMove = head;
//        while(pMove.getNext() != null){
//            if(pMove.getDate() == date){
//                System.out.println(pMove.getDate()+"Find!!!");
//                return;
//            }
//            pMove = pMove.getNext();
//        }
//        System.out.println("Not Find This Node!");
//    }
    //查找结点
    public boolean findNode(int date){
        DoubleNode tmpNode = head;
        if(LinkIsEmpty()){
            System.out.println("Double Link Is Empty!");
            return false;
        }
        while(tmpNode.getDate() != date){
            tmpNode = tmpNode.getNext();
            if(tmpNode.getNext() == null){
                System.out.println("No This DoubleNode!");
                return false;
            }
        }
        System.out.println(tmpNode.getDate());
        return true;
    }

    //修改结点 修改结点前需要判断结点是否存在
    public void modifyNode(int date, int updateDate){
        if(LinkIsEmpty()){
            System.out.println("Link is Empty!");
            return;
        }
        if(!findNode(date)){
            return;
        }
        DoubleNode tempNode = head;
        while(tempNode.getDate() != date){
            tempNode = tempNode.getNext();
        }
        //修改操作
        tempNode.setDate(updateDate);
        System.out.println("MetaDate:"+date+"\tUpdate:"+updateDate+"Successful!");
    }
}
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package 数据结构.链表.双链表;

public class DoubleLinkTest {
    public static void main(String[] args) {
        DoubleNode node1 = new DoubleNode(2);
        DoubleNode node2 = new DoubleNode(34);
        DoubleNode node3 = new DoubleNode(4);

        DoubleLink DL1 = new DoubleLink();
        DL1.printDoubleLink();

        System.out.println(DL1.LinkIsEmpty());
        DL1.addNode(node1);
        DL1.printDoubleLink();


        DL1.addNode(node3);
        DL1.printDoubleLink();

        DL1.addNode(node2);
        DL1.printDoubleLink();


        DoubleNode node4 = new DoubleNode(41);
        DL1.addNode(node4);

        DL1.addNode(new DoubleNode(343));

        DL1.printDoubleLink();
        System.out.println(DL1.findNode(41));

        System.out.println("删除结点操作");
        DL1.delNode(41);

        DL1.printDoubleLink();

        DL1.modifyNode(4,888);
        DL1.printDoubleLink();
    }
}

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