/*
 * @lc app=leetcode id=82 lang=java
 *
 * [82] Remove Duplicates from Sorted List II
 */

// @lc code=start
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode dummy = new ListNode(0);
        ListNode tail = dummy;
        dummy.next = null;
        ListNode cur = head;
        int v;
        while(cur != null) {
            if(cur.next == null || cur.val != cur.next.val) {
                tail.next = cur;
                cur = cur.next;
                tail = tail.next;
                tail.next = null;
            } else {
                v = cur.val;
                while(cur != null && cur.val == v) {
                    cur = cur.next;
                }
            }
        }
        return dummy.next;
    }
}
// @lc code=end