Java递归

class Solution {
    public ListNode deleteDuplication(ListNode head) {
         if(head==null||head.next==null) return head;
         ListNode next=head.next;
         if(head.val==next.val){
             while(next!=null&&head.val==next.val){
                 next=next.next;
             }
             head=deleteDuplication(next);

         }else head.next=deleteDuplication(next);
         return head;
    }
}