练7.2 保留12位小数

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	3149991033	12ms	552 KiB	C	105 Bytes	2024-10-24 20:00:41
AC	Weiyi_Hobe	13ms	256 KiB	C	106 Bytes	2025-4-17 19:52:39
AC	郑式	14ms	520 KiB	C	116 Bytes	2024-9-24 19:57:18
AC	AAA懒大王	14ms	552 KiB	C	104 Bytes	2024-10-20 17:01:17
AC	陈浩彬	14ms	552 KiB	C	95 Bytes	2024-10-21 19:16:38
AC	李一飞	15ms	520 KiB	C	115 Bytes	2024-10-17 17:41:09
AC	石雅妮	15ms	516 KiB	C	107 Bytes	2024-10-17 17:34:33