// 重写
class Solution
{
public:

    ListNode *reverseList(ListNode *head)
    {
        if(head==NULL)
            return NULL;
        else if (head->next == NULL)
            return head;
        else
        {
            ListNode *tmp = reverseList(head->next);
            head->next->next = head;
            head->next = NULL;
            return tmp;
        }
        return reverseList(head);
    }
};