// @Title: 删除排序链表中的重复元素 II (Remove Duplicates from Sorted List II)
// @Author: qisiii
// @Date: 2024-01-14 16:46:32
// @Runtime: 0 ms
// @Memory: 42 MB
// @comment: 递归思路
每轮重复的话就跳过这个节点
这一轮存在重复，那么head直接重新来，等于拿新的节点来计算
如果这一轮不存在重复，那么head节点就是稳定的，从head.next开始计算
// @flag: WHITE
/**
 * 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) {
        if(head==null||head.next==null){
            return head;
        }
        boolean repeat=false;
        while(head!=null&&head.next!=null&&
        head.val==head.next.val){
            repeat=true;
            head=head.next;
        }
        if(repeat){
            head=head.next;
            head=deleteDuplicates(head);
        }else{
            head.next=deleteDuplicates(head.next);
        }
        
        return head;
    }
}

// @Title: 删除排序链表中的重复元素 II (Remove Duplicates from Sorted List II)
// @Author: qisiii
// @Date: 2024-01-15 09:47:27
// @Runtime: 0 ms
// @Memory: 42.2 MB
// @comment: 
// @flag: 
/**
 * 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) {
        if(head==null||head.next==null){
            return head;
        }
        boolean repeat=false;
        while(head!=null&&head.next!=null&&
        head.val==head.next.val){
            repeat=true;
            head=head.next;
        }
        if(repeat){
            head=head.next;
            head=deleteDuplicates(head);
        }else{
            head.next=deleteDuplicates(head.next);
        }
        return head;
    }
}