输出保留 12 位小数的浮点数

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	C23huangminzhe	32ms	756 KiB	C++11	128 Bytes	2023-9-15 20:22:59
AC	C23huangchengfu	36ms	808 KiB	C++11(O2)	483 Bytes	2024-8-5 20:45:55
AC	C24zhuchengyu	39ms	816 KiB	C++11(O2)	122 Bytes	2024-8-20 15:10:44
AC	C23lingyiyu	40ms	808 KiB	C++11(O2)	132 Bytes	2024-7-20 18:50:48
AC	C24zhangzheyuan	40ms	840 KiB	C++11(O2)	123 Bytes	2024-7-18 19:03:30
AC	C23zhangjiawei	41ms	816 KiB	C++11(O2)	132 Bytes	2024-7-17 20:26:01