输出保留 12 位小数的浮点数

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	Harry	32ms	808 KiB	C++14	177 Bytes	2025-8-18 18:50:33
AC	严晨航	32ms	808 KiB	C++14(O2)	143 Bytes	2025-8-26 15:56:04
AC	张叶朵	32ms	816 KiB	C++14(O2)	162 Bytes	2025-8-27 23:11:00
AC	杨家齐xly2025	32ms	728 KiB	C++14(O2)	135 Bytes	2025-8-7 19:39:29
AC	谭博文	33ms	696 KiB	C++14(O2)	136 Bytes	2025-10-7 14:19:40
AC	maochengjun	34ms	808 KiB	C++14	143 Bytes	2025-7-9 11:38:25
AC	张芷若xly2025	34ms	744 KiB	C++14(O2)	145 Bytes	2025-8-7 20:08:12
AC	龙肖瑾xly2025	34ms	728 KiB	C++14(O2)	143 Bytes	2025-7-27 22:03:47
AC	若白	35ms	816 KiB	C++17(O2)	124 Bytes	2025-7-11 14:38:46
AC	sage2012	35ms	808 KiB	C++14(O2)	127 Bytes	2025-9-20 17:17:09
AC	王思懿	35ms	812 KiB	C++14(O2)	145 Bytes	2025-8-18 10:52:34
AC	女乃龙	35ms	824 KiB	C++14(O2)	143 Bytes	2025-7-11 14:41:55
AC	w20120404	36ms	688 KiB	C++14(O2)	139 Bytes	2025-8-19 15:14:45
AC	陈国瑞	36ms	808 KiB	C++14(O2)	157 Bytes	2025-7-15 17:18:47
AC	卢皓禹xly2025	36ms	808 KiB	C++14(O2)	153 Bytes	2025-9-6 16:10:41
AC	lyd	37ms	808 KiB	C++14(O2)	142 Bytes	2025-9-25 17:13:56
AC	_chjich_	39ms	732 KiB	C++14(O2)	124 Bytes	2025-7-11 9:31:56
AC	曾彦彬contest	39ms	804 KiB	C++14(O2)	167 Bytes	2025-7-7 19:41:37
AC	xzh13579	39ms	808 KiB	C++14(O2, GCC 9.3.0)	184 Bytes	2025-7-24 23:23:41
AC	Mch121018	40ms	808 KiB	C++17(O2)	149 Bytes	2025-9-9 22:13:40
AC	刘熠辰	40ms	808 KiB	C++14(O2)	124 Bytes	2025-9-25 15:25:30