[Leetcode] 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

Credits:
Special thanks to @mithmatt for adding this problem and creating all test cases.

 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         if (head == NULL) return NULL;
13         ListNode *cur = head, *next = head->next;
14         while (next != NULL) {
15             if (next->val == val) {
16                 cur->next = next->next;
17                 delete next;
18                 next = cur->next;
19             } else {
20                 cur = cur->next;
21                 next = next->next;
22             }
23         }
24         if (head->val == val) {
25             cur = head;
26             head = head->next;
27             delete cur;
28         }
29         return head;
30     }
31 };