求1+2+3+...+n 的和

状态	递交者	时间	内存	代码	递交时间
AC	Dancs	21ms	7.6 MiB	190 Bytes	2023-10-21 11:20:14
AC	longhaorui	21ms	7.2 MiB	206 Bytes	2023-10-21 11:21:36
AC	johnDeng	21ms	7.2 MiB	342 Bytes	2023-10-21 11:32:27
AC	longhaorui	21ms	7.2 MiB	206 Bytes	2023-10-21 11:22:51
AC	CWj	21ms	7.2 MiB	190 Bytes	2023-10-21 11:22:16
AC	wangqilun23010	22ms	7.6 MiB	193 Bytes	2023-10-21 11:19:48
AC	熊瑾瑜	22ms	7.4 MiB	193 Bytes	2023-10-21 11:15:40
AC	longhaorui	25ms	6.9 MiB	171 Bytes	2023-8-18 18:33:25