Leetcode: Remove Duplicates from Sorted List

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