Java 递归

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