输出保留 3 位小数的浮点数

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	C23huangminzhe	34ms	808 KiB	C++11	126 Bytes	2023-9-15 20:22:04
AC	C23huangchengfu	38ms	808 KiB	C++11(O2)	481 Bytes	2024-8-5 20:45:52
AC	C24zhuchengyu	39ms	816 KiB	C++11(O2)	120 Bytes	2024-8-20 15:09:15
AC	C23lingyiyu	40ms	792 KiB	C++11(O2)	128 Bytes	2024-7-20 18:50:34
AC	C23zhangjiawei	40ms	848 KiB	C++11(O2)	128 Bytes	2024-7-17 19:58:01
AC	C24zhangzheyuan	41ms	808 KiB	C++11(O2)	119 Bytes	2024-7-18 18:53:57
AC	C23liukaiyan	42ms	880 KiB	C++11(O2)	108 Bytes	2024-7-10 20:57:02