java数据结构与算法--双端链表链表与双向链表

1、双端链表

package com.evior.linklist;

public class Node {

    //数据域
    public long data;
    //指针域
    public Node next;

    public Node(long value) {
        this.data=value;
        next=null;
    }

    /**
     * 显示的方法
     */
    public void  display(){
        System.out.println(data+" ");
    }
}

package com.evior.linklist2;

import com.evior.linklist.Node;

public class LinkList2 {

    //头节点
    private Node first;

    //尾节点

    private Node last;

    public LinkList2(){
        first=null;
        last=null;
    }


    //插入(从头)
    public void insertFirst(long value){
        Node node=new Node(value);
        if (isEmpty()){
            last=node;
        }
        node.next=first;
        first=node;
    }


    //插入（从尾）
    public void insertLast(long value){
        Node node=new Node(value);
        if (isEmpty())
        {
            first=node;
        }else {
            last.next=node;
        }
        last=node;
    }

    //删除
    public Node deleteFirst(){
        Node temp=first;
        if (first.next==null){
            last=null;
        }
        first=temp.next;
        return temp;
    }

    //打印
    public void display(){
        Node current=first;
        while (current!=null){
            current.display();
            current=current.next;
        }
    }


    //查找的方法
    public Node find(long value){
        Node current=first;
        while (current.data!=value){
            if (current==null){
                return null;
            }
            current=current.next;
        }
        return current;
    }

    //删除方法，根据数据域来进行删除
    public Node delete(long value){
        Node current=first;
        Node previous=first;
        while (current.data!=value){
            if (current==null){
                return null;
            }
            previous=current;
            current=current.next;
        }
        //判断删除的是否为头结点
        if (current!=first){
            previous.next=current.next;
            current.next=null;
        }else {
            current=first;
            first=current.next;
            current.next=null;
            last=null;
        }
        return current;
    }


    /**
     * 判断是否为空
     * @return
     */
    public boolean isEmpty(){
        return first==null;
    }
}

2、测试

package com.evior.linklist2;

public class Test {



    public static void main(String[] args) {
        LinkList2 linkList2=new LinkList2();

        linkList2.insertFirst(1);
        linkList2.insertFirst(2);
        linkList2.insertLast(0);
        linkList2.display();
        linkList2.deleteFirst();
        linkList2.display();
        linkList2.delete(1).display();
        linkList2.display();
        linkList2.find(0).display();
    }
}

3、结果

4、双向链表

package com.evior.doublelinklist;

public class Node {

    //数据域
    public long data;
    //指针域
    public Node next;

    public Node previous;

    public Node(long value) {
        this.data=value;
        next=null;
        previous=null;
    }

    /**
     * 显示的方法
     */
    public void  display(){
        System.out.println(data+" ");
    }
}

package com.evior.doublelinklist;

public class DoubleLinkList {

    //头结点
    private Node first;


    //尾节点
    private Node last;


    public DoubleLinkList(){
        first=null;
        last=null;
    }


    /**
     * 插入一个结点，在头结点后进行插入
     * @param value
     */
    public void insertFirst(long value){
        Node node=new Node(value);
        //判断是否为空
        if (isEmpty()){
            last=node;
        }else {
            first.previous=node;
        }
        node.next=first;
        first=node;
    }


    /**
     * 插入一个结点，从尾结点进行插入
     */
    public void insertLast(long value){
        Node node=new Node(value);
        if (isEmpty()){
            first=node;
            last=node;
        }else {
            last.next=node;
            node.previous=last;
            last=node;
        }

    }


    /**
     * 删除头节点
     * @return
     */
    public Node deleteFirst(){
        Node current=first;
        if (first.next==null){
            last=null;
            first=null;
            return current;
        }else {
            first.next.previous=null;
            first=current.next;
            return current;
        }
    }


    /**
     * 删除尾节点
     * @return
     */
    public Node deleteLast(){
        Node current=last;
        if (current.previous==null){
            last=null;
            first=null;
            return current;
        }else {
            current.previous.next=null;
            last=current.previous;
            return current;
        }
    }


    /**
     * 显示方法
     */
    public void display() {
        Node current = first;
        while(current != null) {
            current.display();
            current = current.next;
        }
        System.out.println();
    }


    /**
     * 查找
     */
    public Node find(long value){
        Node current=first;
        while (current.data!=value){
            if (current.next==null){
                return null;
            }
            current=current.next;
        }
        if(current == first) {
            first = first.next;
        } else {
            current.previous.next = current.next;
        }
        return current;

    }


    /**
     * 判断是否为空
     */
    public boolean isEmpty() {
        return (first == null);
    }

}

5、测试

package com.evior.doublelinklist;

public class Test {

    public static void main(String[] args) {
        DoubleLinkList doubleLinkList=new DoubleLinkList();
        doubleLinkList.insertFirst(1);
        doubleLinkList.insertFirst(2);

        doubleLinkList.insertLast(3);
        doubleLinkList.insertLast(4);

        doubleLinkList.display();
        doubleLinkList.deleteFirst();
        doubleLinkList.display();
        doubleLinkList.deleteLast();
        doubleLinkList.display();

        doubleLinkList.find(1).display();
    }
}

6、结果