Java数据结构--链表节点

java中的指针

public class Test {
    public static void main(String [] args){
      A a=new A();//a是一个对象
        A b=a;A c=a;//b 和 c都是指向同一个对象a的指针
        b.a=20;//b是指针 这里其实修改了a.a
        System.out.println(c.a);//c也是指向a的指针 //所以输出20
    }
}
class A{
    int a=10;
}

利用指针写一个简单的的单向链表

class ListNode<E> {
    private E item;//存放泛型变量
    public ListNode<E> next;//这是指针

    public ListNode(E thatItem) {
        this.item = thatItem;
        next = null;//初始指针指向null
    }

    public void setNext(E target) {
        next = new ListNode(target);//把指针指向一个构造出来的对象
    }

    public E getItem() {
        return this.item;
    }

    public void setItem(E thatItem) {
        this.item = thatItem;
    }
}

一个简单的双向链表

public class DoubleListNode<E> {
    private ListNode front;
    public DoubleListNode(E item) {//constructor
       front=new ListNode(item);

    }
    public void addTop(E target){//类似链表栈的push
        front =front.ListNodeNext(target,front) ;
    }
    public void addBack(E target){//类似链表栈的add
        ListNode node=front;
        for(;node.getNext()!=null;node=node.getNext()){

         }
        node.setNext(new ListNode(target));
    }

}
class Main{
    public static void main(String[] args){
       DoubleListNode ls=new DoubleListNode("a");
        ls.addBack("b");
        ls.addTop("c");
    }
}

public class ListNode<E> {//双向节点
    private E item;  //节点的item
    private ListNode<E> next; //左指针
    private ListNode<E> pre;//右指针

    public ListNode(E item) { //constructor
        this.item = item;
        next = null;
        pre = null;
    }
    public ListNode ListNodeNext(E item,ListNode thatNext){//类似链表栈的push
        ListNode node =new ListNode(item);
        node.setNext(this);
        this.pre=node;
        return node;
    }
    public ListNode ListNodePre(E item,ListNode thatNext){//类似链表栈的push
        ListNode node =new ListNode(item);
        node.setPre(this);
        this.next=node;
        return node;
    }

    public E getItem() {
        return item;
    }

    public ListNode<E> getNext() {
        return next;
    }

    public void setItem(E item) {
        this.item = item;
    }

    public void setNext(ListNode<E> thatNext) {//使用tahtNext 设置两条链接
        this.next = thatNext;
        thatNext.pre=this;
    }

    public ListNode<E> getPre() {
        return pre;
    }

    public void setPre(ListNode thatPre) {
        this.pre = thatPre;
        thatPre.next=this;  //设置两条链接
    }

}