判断元素是否存在

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	C23caimingfeng	33ms	404 KiB	C++11	375 Bytes	2024-1-25 8:58:13
AC	C23guanhonggang	34ms	508 KiB	C++11	410 Bytes	2024-1-23 11:28:55
AC	C23lingyiyu	34ms	408 KiB	C++11	375 Bytes	2024-1-23 11:17:53
AC	C23huangzhiyuan	34ms	404 KiB	C++11	375 Bytes	2024-3-23 10:55:20
AC	C23chensiyu	35ms	404 KiB	C++11	311 Bytes	2024-1-23 11:32:21
AC	C23zhanghao	35ms	404 KiB	C++11	375 Bytes	2024-1-24 9:38:59
AC	C23huangyuran	35ms	404 KiB	C++11	269 Bytes	2024-10-22 13:44:49
AC	C23huyating	35ms	508 KiB	C++11	345 Bytes	2024-1-24 10:10:22
AC	C23wutongyu	35ms	404 KiB	C++11	372 Bytes	2024-1-28 10:21:06
AC	C23pengweixuan	36ms	404 KiB	C++11	345 Bytes	2024-1-23 11:21:33
AC	C23xiehaoxuan	36ms	508 KiB	C++11	375 Bytes	2024-1-27 11:18:53
AC	C23chenxinglin	36ms	404 KiB	C++11	375 Bytes	2024-1-26 9:52:55
AC	C23zhangshangkuan	36ms	404 KiB	C++11	375 Bytes	2024-1-28 11:55:33
AC	C23lvzekai	36ms	404 KiB	C++11	697 Bytes	2024-1-26 13:35:31
AC	C22hepeilin	36ms	404 KiB	C++11	375 Bytes	2024-1-27 9:16:42
AC	C23linboming	36ms	408 KiB	C++11	375 Bytes	2024-1-23 11:20:21
AC	C23yuzirui	36ms	404 KiB	C++11	425 Bytes	2024-1-23 11:55:44
AC	C24zhaozicheng	36ms	408 KiB	C++11	414 Bytes	2025-2-8 21:38:39
AC	C23fufuhang	36ms	404 KiB	C++11	345 Bytes	2024-1-26 9:49:38
AC	C23huangyuanhao	36ms	408 KiB	C++11	375 Bytes	2024-1-28 9:33:54
AC	C23luohaotian	36ms	404 KiB	C++11	440 Bytes	2024-1-23 14:53:22
AC	C23liyanlan	37ms	508 KiB	C++11	375 Bytes	2024-1-26 10:10:07
AC	C24zhangzheyuan	37ms	408 KiB	C++11	440 Bytes	2024-10-30 17:13:06
AC	C24zhengfujia	37ms	408 KiB	C++11	333 Bytes	2025-3-19 20:43:10
AC	C23fengrui	37ms	404 KiB	C++14	375 Bytes	2024-1-25 9:30:42
AC	C23zhangjiawei	37ms	508 KiB	C++11	182 Bytes	2024-3-9 16:13:32
AC	C23liupeilin	37ms	508 KiB	C++11	411 Bytes	2024-1-23 11:15:00
AC	C24wanghongming	37ms	404 KiB	C++11	355 Bytes	2025-3-14 9:58:22
AC	C24kongxiangtai	38ms	408 KiB	C++11	400 Bytes	2025-4-3 14:01:45
AC	C23liwenyu	38ms	508 KiB	C++11	375 Bytes	2024-1-23 11:33:14