数据结构-双端链表

package 双端链表;

public class Link {

    public double data;
    public Link next;
    
    public Link(double d)
    {
        data = d;
    }
    
    //打印节点的方法
    public void displayLink()
    {
        System.out.print(data+"  ");
    }
    
}
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package 双端链表;

public class LinkLastFirst {

    private Link first;
    private Link last;
    
    public LinkLastFirst()
    {
        first = null;
        last = null;
    }
    //双端链表的头插入的实现
    public void insertFirst(double data)
    {
        Link newLink = new Link(data);
        if(isEmpty())
        {
            last = newLink;
        }
        else{
            newLink.next = first;
        }
            first = newLink;
        
    }
    private boolean isEmpty() {
        //判断双端链表是不是为空
        if(first == null)
        {
            return true;
        }
        return false;
    }
    
    //尾插法的实现
    public void insertLast(double data)
    {
        Link newLink = new Link(data);//生成的新的链接点
        if(isEmpty())
        {
            first = newLink;
        }else{
            last.next = newLink;
        }
            last = newLink;
        
        
    }
    
    //删除第一个节点的方法的实现
    public double deleteFirst()
    {
        double data = first.data;
        if(first.next == null)
        {
            last = null;
            
        }else{
            first = first.next;
            
        }
        return data;
        
        
    }
    
    
    public void displayList()
    {
        Link current =first;
        while(current != null)
        {
            current.displayLink();
            current = current.next;
        }
        System.out.println("  ");
    }
    
    
    
    
}