[LeetCode] 82. Remove Duplicates from Sorted List II

public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head==null) return head;
        ListNode fakeHead=new ListNode(0);//新建一个头结点
        fakeHead.next=head;
        ListNode pre=fakeHead, cur=head;
        while(cur!=null){
            while(cur.next!=null&&cur.val==cur.next.val)
                cur=cur.next;
            if(pre.next==cur)//相邻元素没有重复
                pre=pre.next;
            else 
            pre.next=cur.next;
            cur=cur.next;
          }
        return fakeHead.next;
    }
}

public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
            if(head==null) return head;
        if(head.next!=null&&head.next.val==head.val){
                while(head.next!=null&&head.next.val==head.val)//循环直到找到一个不重复的node
                    head=head.next;

            return deleteDuplicates(head.next);
        }
        else head.next=deleteDuplicates(head.next);//相邻无重复
        return head;
        }
}