链表

 1 package struct;
 2 
 3 /**
 4  * Created by moi on 2017/10/18.
 5  */
 6 public class LinkList {
 7     /**
 8      * Definition for singly-linked list.
 9      */
10     public class ListNode {
11         int val;
12         ListNode next;
13 
14         ListNode(int x) {
15             val = x;
16         }
17     }
18 
19 
20     /**
21      * 移除链表相同值
22      * @param head a ListNode
23      * @param val  an integer
24      * @return a ListNode
25      */
26     public ListNode removeElements(ListNode head, int val) {
27         if (head == null) {
28             return null;
29         }
30         if (head.next == null) {
31             if (head.val == val) {
32                 return null;
33             } else {
34                 return head;
35             }
36         }
37         ListNode current = head;
38         ListNode pre = null;
39         boolean flag = false;
40         while (current.next != null) {
41             if (current.val == val) {
42                 if (pre != null) {
43                     pre.next = current.next;
44                 }
45                 current = current.next;
46             } else {
47                 pre = current;
48                 if (flag == false) {
49                     head = current;
50                     flag = true;
51                 }
52                 current = current.next;
53             }
54         }
55         if (pre == null) {
56             return null;
57         }
58         if (current.next == null) {
59             if (current.val == val) {
60                 pre.next = null;
61             }
62         }
63         return head;
64 
65     }
66     
67 }