LeetCode - Remove Duplicates from Sorted List II - GoldmanSachs - Easy - C+++

 ListNode* deleteDuplicates(ListNode *head){
        if(head == NULL || head -> next == NULL){
            return head;
        }
        ListNode* kow = head -> next;
        if(kow -> val == head -> val){
            while(kow != NULL and head -> val == kow -> val){
                kow = kow -> next;
            }
            return deleteDuplicates(kow);
        }else{
            head -> next = deleteDuplicates(kow);
            return head;
        }
    }