This problem is used in private contest:程序设计原理_课堂练习1
[2020CIC] 2020 Programming Principle C/C++ Course Practice #1
[2021程序设计]课堂练习1
2021 程序设计原理 课堂练习 1 [05138, 03458班]
2021 程序设计原理 课堂练习 1 [03457班]