重复的保留一个node

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
public ListNode deleteDuplicates(ListNode head) {
    if(head == null){
        return null;
    }
    ListNode newhead = new ListNode(-1, head);
    ListNode cur = head;
    ListNode before = newhead;

    while(cur.next != null){
        if(cur.val == cur.next.val){
            before.next = cur.next;
            //System.out.print("here");
        }
        else{
            before = before.next;
        }
        
        
        cur = cur.next;
    }

    return newhead.next;
}

重复都删除

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
public ListNode deleteDuplicates(ListNode head) {
    if(head == null){
        return null;
    }
    ListNode newhead = new ListNode(-1, head);
    
    ListNode cur = head;
    ListNode before = newhead;

    while(cur != null && cur.next != null){
        if(cur.val == cur.next.val){
            ListNode end = cur.next;
            while(cur.val == end.val){
                if(end.next == null){
                    end = null;
                    break;
                }
                else{
                   end = end.next; 
                }
                
            }
            before.next = end;
            cur = end;
            //System.out.print("cur val "+ cur.val+"\n");
        }
        else{
            before = before.next;
            cur = cur.next;
        }
    }
    return newhead.next;
}