HJ11 数字颠倒题目：https://www.nowcoder.com/practice/ae809795fca34687a48b172186e3dafe?tpId=37&tqId=21234&rp=1&ru=/exam/oj/ta&qru=/exam/oj/ta&sourceUrl=%2Fexam%2Foj%2Fta%3FtpId%3D37&difficulty=undefined&judgeStatus=undefined&tags=