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.

Wrong Edition.

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        if(!head) return head;
        if(!head->next) return head->val == val ? NULL : head;
        
        while(head->val == val)
            head = head->next; //avoid the case where continuous val at the head
        if(!head) return NULL;
        
        ListNode* current = head;
        while(current){
            if(current->next->val == val){
                ListNode* temp = current->next;
                while(temp && temp->val == val)
                    temp = temp->next;
                current->next = temp;
            }
            current = current->next;
        }
        return head;
    }
};

Runtime: 36ms

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        if(!head) return head;
        
        ListNode* pre = new ListNode(0);
        pre->next = head;
        ListNode* move = pre;
        
        while(move->next){
            if(move->next->val == val)
                move->next = move->next->next;
            else
                move = move->next;
        }
        return pre->next;
    }
};