83. Remove Duplicates from Sorted List

    public ListNode deleteDuplicates(ListNode head) {
        if(head == null) {
            return null;
        }
        ListNode dummy = new ListNode(-1);
        dummy.next = head;
        while(head != null && head.next != null) {
            if(head.val == head.next.val) {
                head.next = head.next.next;
            } else {
                head = head.next;
            }
        }
        return dummy.next;
    }

第10行是else，不是每次执行，这样连续重复数字才能被处理