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  *     ListNode *next;
 6  *     ListNode(int x) : val(x), next(NULL) {}
 7  * };
 8  */
 9 class Solution {
10 public:
11     ListNode* removeElements(ListNode* head, int val) {
12         
13         ListNode node(-1);
14         node.next=head;
15         ListNode *pre=&node;
16         while(head!=NULL)
17         {
18             if(head->val==val)
19             {
20                 pre->next=head->next;
21                 delete head;
22                 head=pre->next;
23             }
24             else
25             {
26                 pre=pre->next;
27                 head=head->next;
28             }
29 
30         }
31         return node.next;
32     }
33 };