[leetcode] Remove Duplicates from Sorted List II

public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode newHead = new ListNode(-1);
        newHead.next = head;
        ListNode pre = newHead;
        ListNode cur = head;

        while (cur != null && cur.next != null) {
            if (cur.val == cur.next.val) {
                while (cur != null && cur.next != null && cur.val == cur.next.val) {
                    cur = cur.next;
                }
                cur = cur.next;
                pre.next = cur;
            }

            else {
                pre = cur;
                cur = cur.next;
            }

        }

        return newHead.next;

    }

    public static void main(String[] args) {
        ListNode head = ListUtils.makeList(1, 1, 2, 3, 3);
        ListUtils.printList(head);
        head = new Solution().deleteDuplicates(head);
        ListUtils.printList(head);
    }

}