统计一个数中7和9的个数

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	王梓宸W	3ms	376 KiB	C++14(O2)	240 Bytes	2025-3-13 19:40:38
AC	徐崇瑞	3ms	376 KiB	C++14(O2)	178 Bytes	2026-3-30 19:01:49
AC	刘金诚	3ms	376 KiB	C++14(O2)	236 Bytes	2025-3-18 19:49:14
AC	丁奕轩	3ms	376 KiB	C++14(O2)	214 Bytes	2026-3-30 19:09:50
AC	张博森0903	3ms	380 KiB	C++14	245 Bytes	2025-3-11 23:06:08
AC	盛俊祎	4ms	504 KiB	C++14(O2)	248 Bytes	2026-4-5 20:37:34
AC	黄蕴之	4ms	504 KiB	C++14(O2)	191 Bytes	2026-3-31 18:06:00
AC	董峻熙	4ms	528 KiB	C++14(O2)	271 Bytes	2025-10-22 16:54:22
AC	杭芊帆2	4ms	376 KiB	C++14(O2)	205 Bytes	2026-4-5 16:32:44
AC	张佳硕	4ms	376 KiB	C++14(O2)	195 Bytes	2026-3-31 21:39:35
AC	周敬轩	4ms	412 KiB	C++14(O2)	204 Bytes	2026-4-5 16:35:45
AC	李东骏	4ms	408 KiB	C++14	260 Bytes	2025-3-9 11:25:03
AC	程梓萱	4ms	384 KiB	C++14(O2)	407 Bytes	2025-3-9 0:36:28
AC	王辰鑫	4ms	376 KiB	C++14(O2)	191 Bytes	2026-2-8 11:10:18
AC	周圣博	4ms	372 KiB	C++14(O2)	233 Bytes	2025-3-10 22:31:59
AC	赵祥成	4ms	376 KiB	C++14(O2)	231 Bytes	2026-2-8 11:15:46
AC	杨宸	4ms	376 KiB	C++14(O2)	218 Bytes	2026-3-22 17:10:31
AC	xiezhuoyou	4ms	388 KiB	C++14(O2)	305 Bytes	2025-12-13 12:01:07
AC	方子睿	4ms	384 KiB	C++14(O2)	208 Bytes	2025-12-10 18:12:34
AC	吕剑秋	4ms	504 KiB	C++14(O2)	249 Bytes	2025-10-23 20:45:04
AC	ymhxxyz	4ms	500 KiB	C++14	240 Bytes	2025-4-26 13:57:23
AC	孙渤淘	4ms	384 KiB	C++14(O2)	230 Bytes	2026-3-22 17:09:53
AC	盼盼测试号	4ms	376 KiB	C++14(O2)	219 Bytes	2025-7-11 15:07:29
AC	李新屹	4ms	384 KiB	C++14(O2)	205 Bytes	2026-2-8 11:19:16
AC	鲍佳慧	4ms	420 KiB	C++14	280 Bytes	2025-10-6 10:55:29
AC	jasonXu	4ms	376 KiB	C++14(O2)	245 Bytes	2025-7-18 14:42:49
AC	于子洋	4ms	504 KiB	C++14(O2)	270 Bytes	2025-10-14 19:26:18
AC	谢文铄	4ms	376 KiB	C++14	304 Bytes	2026-1-30 15:10:48
AC	张尚	4ms	504 KiB	C++14(O2)	261 Bytes	2025-3-13 19:29:43
AC	15153285272	4ms	384 KiB	C++14	229 Bytes	2025-12-11 21:09:57
AC	陈易凡	4ms	380 KiB	C++14(O2)	228 Bytes	2025-3-15 12:53:22
AC	yangzhili	4ms	416 KiB	C++14(O2)	308 Bytes	2025-11-16 12:48:44
AC	王恒悦	4ms	516 KiB	C++14(O2)	250 Bytes	2026-2-8 11:08:50
AC	18953256693	4ms	412 KiB	C++14(O2)	230 Bytes	2025-12-6 19:30:08
AC	杜若铭	4ms	504 KiB	C++14	732 Bytes	2025-4-26 14:46:31
AC	管鋡希	4ms	504 KiB	C++14(O2)	254 Bytes	2026-3-22 16:31:48
AC	高源鸿	4ms	376 KiB	C++14(O2)	220 Bytes	2026-2-8 11:11:10
AC	王彤鑫	4ms	376 KiB	C++14(O2)	208 Bytes	2026-2-8 11:06:51
AC	王昭蒙	4ms	416 KiB	C++14(O2)	311 Bytes	2025-12-23 21:31:10
AC	lishuxi	4ms	364 KiB	C++17(O2)	296 Bytes	2025-4-26 14:46:49
AC	蔡艺赫	4ms	424 KiB	C++98	261 Bytes	2025-12-6 18:09:31
AC	wangjianlin	4ms	544 KiB	C++11	316 Bytes	2025-5-4 18:50:12
AC	秦鹏越	4ms	376 KiB	C++14	241 Bytes	2025-10-25 17:31:52
AC	李沐麟	4ms	424 KiB	C++14(O2)	221 Bytes	2025-12-4 18:43:29
AC	karry	4ms	376 KiB	C++14	218 Bytes	2025-4-26 15:21:30
AC	刘恩成	4ms	504 KiB	C++14(O2)	223 Bytes	2026-3-22 16:40:19
AC	郭宸硕	4ms	504 KiB	C++11	213 Bytes	2026-1-30 8:56:12
AC	陈炎朔	4ms	376 KiB	C++14	339 Bytes	2025-12-13 16:16:56
AC	杭芊羽2	4ms	376 KiB	C++14(O2)	196 Bytes	2026-3-22 17:03:30
AC	朱芫墨	4ms	420 KiB	C++14	289 Bytes	2025-12-12 19:06:02
AC	王艺喆	4ms	412 KiB	C++14(O2)	252 Bytes	2025-12-6 20:05:06
AC	糖糖	4ms	504 KiB	C++14(O2)	246 Bytes	2025-4-26 15:19:17
AC	许家瑜	5ms	424 KiB	C++14(O2)	207 Bytes	2025-12-7 12:13:42