203. Remove Linked List Elements (List)

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

/**
* 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) {
ListNode* newHead = new ListNode(0);
newHead->next = head;
ListNode* pre = newHead;
ListNode* cur = head;

while(cur){
if(cur->val == val){
pre->next = cur->next;
}
else{
pre = pre->next;
}
cur = cur->next;
}
return newHead->next;
}
};