题解 | #删除有序链表中重复的元素-II#

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    public ListNode deleteDuplicates (ListNode head) {
        // write code here
        ListNode node = head;
        ListNode newHead = new ListNode(-1);
        newHead.next = head;
        ListNode pre = newHead;
        while(node != null){
            if(node.next == null || node.val != node.next.val){
                pre = pre.next;
                node = node.next;
            }else{
                while(node.next != null && node.val == node.next.val){
                    node = node.next;
                }
                pre.next = node.next;
                node = node.next;
            }
        }
        return newHead.next;
    }
}