《Java数据结构与算法》笔记-CH5-链表-3双端链表 

  1 /**
  2  * 双端链表的实现
  3  */
  4 class LinkA {
  5     public long dData;
  6     public LinkA next;
  7 
  8     public LinkA(long d) {
  9         dData = d;
 10     }
 11 
 12     public String toString() {
 13         return "[" + dData + "]";
 14     }
 15 
 16     public void displayLink() {
 17         System.out.println(toString());
 18     }
 19 }
 20 
 21 class FirstLastList {
 22     private LinkA first;// 头部
 23     private LinkA last;// 尾部
 24 
 25     public FirstLastList() {
 26         first = null;
 27         last = null;
 28     }
 29 
 30     public boolean isEmpty() {
 31         return first == null;
 32     }
 33 
 34     /**
 35      * 在头部插入节点
 36      */
 37     public void insertFirst(LinkA l) {
 38         if (isEmpty())
 39             last = l;
 40         l.next = first;
 41         first = l;
 42     }
 43 
 44     /**
 45      * 在尾部插入节点
 46      * 
 47      * @param l
 48      */
 49     public void insertLast(LinkA l) {
 50         if (isEmpty())
 51             first = l;
 52         else
 53             last.next = l;
 54         last = l;
 55     }
 56 
 57     /**
 58      * 从头部删除一个节点
 59      * 
 60      * @return
 61      */
 62     public long deleteFirst() {
 63         long temp = first.dData;
 64         if (first.next == null)
 65             last = null;
 66         first = first.next;
 67         return temp;
 68     }
 69 
 70     public String toString() {
 71         if (isEmpty())
 72             return "{}";
 73         LinkA current = first;
 74         StringBuilder sb = new StringBuilder();
 75         sb.append("{");
 76         while (current != null) {
 77             sb.append(current.toString()).append(",");
 78             if (current.next == null)
 79                 break;
 80             else
 81                 current = current.next;
 82         }
 83         sb.deleteCharAt(sb.length() - 1);
 84         sb.append("}");
 85         return sb.toString();
 86     }
 87 
 88     public void displayList() {
 89         System.out.println(toString());
 90     }
 91 }
 92 
 93 public class FirstLastListDemo {
 94     public static void main(String[] args) {
 95         FirstLastList fll = new FirstLastList();
 96         for (int i = 1; i < 10; i++) {
 97             System.out.println("插入:"+i);
 98             if (i % 2 == 0)//i为偶数调用insertFirst
 99                 fll.insertFirst(new LinkA(i));
100             else//i为基数调用insertLast
101                 fll.insertLast(new LinkA(i));
102             fll.displayList();
103         }
104         System.out.println("插入完毕开始从头部删除");
105         while(!fll.isEmpty()){
106             fll.deleteFirst();
107             fll.displayList();
108         }
109     }
110 }

 

posted @ 2016-06-24 04:20  fstack  阅读(162)  评论(0)    收藏  举报