11、链表反转

• 输入: 1->2->3->4->5->NULL
  输出: 5->4->3->2->1->NULL

public ListNode reverseList(ListNode head) {
        ListNode cur = null, pre = head;
        while(pre != null){
            ListNode t = pre.next;
            pre.next = cur;
            cur = pre;
            pre = t;
        }
        return cur;
    }

运行结果