203. Remove Linked List Elements

Remove all elements from a linked list of integers that have value val.

Example
Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6
Return: 1 --> 2 --> 3 --> 4 --> 5

 1 /**
 2  * Definition for singly-linked list.
 3  * struct ListNode {
 4  *     int val;
 5  *     struct ListNode *next;
 6  * };
 7  */
 8 struct ListNode* removeElements(struct ListNode* head, int val) {
 9     struct ListNode* cur;
10     struct ListNode* pre;
11     if(NULL == head)
12         return head;
13     cur = head;
14     pre = head;
15     while(cur != NULL)
16     {
17         if(val == head->val)               //注意删除头结点的情况！
18         {
19             head = head->next;
20             cur = head;
21             pre = head;
22             continue;
23         }
24         if(val == cur->val)
25         {
26             pre->next = cur->next;
27             cur = cur->next;
28             continue;
29         }
30         pre = cur;
31         cur = cur->next;
32     }
33     return head;
34 }