Java实现双向循环链表的基本操作

  1 package Eric.ADT;
  2
  3 /**
  4  * <p>
  5  * Title:doubleLinkedList
  6  * </p>
  7  * <p>
  8  * Description:用java实现双向循环链表的基本操作
  9  * </p>
 10  * <p>
 11  * Location:Frostburg
 12  * </p>
 13  *
 14  * @author: Eric.Chen
 15  * @date:2017年9月23日下午12:54:05
 16  */
 17 public class doubleLinkedList {
 18     class Node {// 节点元素
 19         private Node prev;
 20         public Object value;
 21         private Node next;
 22     }
 23
 24     private Node header = null;
 25
 26     void initiate()// 初始化链表
 27     {
 28         header = new Node();
 29         header.prev = header;
 30         header.value = null;
 31         header.next = header;
 32     }
 33
 34     public void insertList(int i, Object n)// 在链表的i位置插入元素n
 35     {
 36         if (i <= 0 || i > size()) {
 37             System.out.println("插入位置不合法！！！" + "链表长度为:" + size());
 38         } else {
 39             Node e = new Node();
 40             e.value = n;
 41             if (header.prev == header)// 说明这是第一次插入元素，在头结点后面插入元素
 42             {
 43                 e.prev = header;
 44                 e.next = header;
 45                 header.next = e;
 46                 header.prev = e;
 47
 48             } else if (i == size())// 在最后插入元素
 49             {
 50                 e.next = header;
 51                 e.prev = header.prev;
 52                 header.prev.next = e;
 53                 header.prev = e;
 54             } else {// 在i位置插入元素
 55                 Node temp = header;
 56                 int count = 0;
 57                 while (temp.next != header) {
 58                     count++;
 59                     if (count == i) {
 60                         e.next = temp.next;
 61                         e.prev = temp;
 62                         temp.next.prev = e;
 63                         temp.next = e;
 64
 65                     }
 66                     temp = temp.next;
 67                 }
 68
 69             }
 70         }
 71     }
 72
 73     public void deleteByIndex(int i)// 删除指定位置上的元素
 74     {
 75         if (i <= 0 || i > size()) {
 76             System.out.println("删除的位置误" + "链表长度为:" + size());
 77         } else {
 78             Node temp = header;
 79             int count = 0;
 80             while (temp.next != header) {
 81                 count++;
 82                 if (count == i) {
 83                     temp.next = temp.next.next;
 84                     temp.next.prev = temp;
 85
 86                 }
 87
 88                 temp = temp.next;
 89             }
 90
 91         }
 92
 93     }
 94
 95     public int size()// 返回链表的长度
 96     {
 97         int count = 1;
 98         Node temp = header;
 99         while (temp.next != header) {
100             count++;
101             temp = temp.next;
102         }
103
104         return count;
105     }
106
107     public void printList() {
108         Node temp = header;
109         while (temp.next != header) {
110             System.out.print(temp.next.value + " ");
111             temp = temp.next;
112         }
113     }
114
115     public void deleteByEle(Object element)// 删除链表中指定元素
116     {
117         Node temp = header;
118         int count = 0;
119         int num = 0;
120         while (temp.next != header) {
121             count++;
122             if (temp.next.value == element) {
123                 num = count;
124             }
125             temp = temp.next;
126         }
127         deleteByIndex(num);
128     }
129
130     public Object findEleByIndex(int i) {
131         int count = 0;
132         Object p = null;
133         if (i <= 0 || i > size()) {
134             System.out.println("输入数据有错！" + size());
135             return -1;
136         } else {
137             Node temp = header;
138             while (temp.next != header) {
139                 count++;
140                 if (count == i) {
141                     p = temp.next.value;
142                 }
143                 temp = temp.next;
144             }
145         }
146         return p;
147     }
148
149     public static void main(String[] args) {
150         doubleLinkedList list = new doubleLinkedList();
151         list.initiate();
152         for (int i = 1; i <= 10; i++) {
153             list.insertList(i, i);
154         }
155         System.out.println("原来的链表为:");
156         list.printList();
157         System.out.println();
158         System.out.println("链表的长度为:" + list.size());
159         /*list.deleteByEle(8);
160         System.out.println("删除元素后的链表为:");
161         list.printList();
162         System.out.println();
163         System.out.println("删除元素后的链表的长度为:" + list.size());*/
164         int idem =(int) list.findEleByIndex(8);
165         System.out.println(idem);
166
167     }
168 }