1 package com.liu.Link;
 2 
 3 //双端链表
 4 public class FirstLastList {
 5     private LinkLast first;
 6     private LinkLast last;
 7     public FirstLastList()
 8     {
 9         first = null;
10         last = null;
11     }
12     
13     public boolean isEmpty()
14     {
15         return first == null;
16     }
17     
18     public void insertFirst(long d)
19     {
20         LinkLast newLink = new LinkLast(d);
21         if(isEmpty())
22         {
23             last = newLink;
24         }
25         newLink.next = first;
26         first = newLink;
27     }
28     
29     public long deleteFirst()
30     {
31         long temp = first.dData;
32         if(first.next == null)
33             last = null;
34         first = first.next;
35         return temp;
36     }
37     
38     public void insertLast(long d)
39     {
40         LinkLast newLink = new LinkLast(d);
41         if(isEmpty())
42         {
43             first = newLink;
44         }else
45         {
46             last.next = newLink;
47         }
48         last = newLink;
49     }
50     
51     public void displayLast()
52     {
53         System.out.print("List (first-->last):");
54         LinkLast current = first;
55         while(current!=null)
56         {
57             current.display();
58             current = current.next;
59         }
60         System.out.println();
61     }
62 }
63 class LinkLast
64 {
65     public long dData;
66     public LinkLast next;
67     
68     public LinkLast(long dd)
69     {
70         dData = dd;
71     }
72     
73     public void display()
74     {
75         System.out.print(dData+" ");
76     }
77 }
78 
79 class FirstLastApp
80 {
81     public static void main(String[] args)
82     {
83         FirstLastList theList = new FirstLastList();
84         theList.insertFirst(22);
85         theList.insertFirst(44);
86         theList.insertFirst(66);
87         
88         theList.insertLast(11);
89         theList.insertLast(33);
90         theList.insertLast(55);
91         
92         theList.displayLast();
93         theList.deleteFirst();
94         theList.deleteFirst();
95         
96         theList.displayLast();
97     }
98 }