字符串的展开

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	maxinyue	18ms	752 KiB	C++11(O2)	945 Bytes	2025-8-18 11:12:33
AC	lilyjiang	19ms	532 KiB	C++14(O2)	903 Bytes	2025-8-10 12:49:06
AC	tangyiqi	19ms	536 KiB	C++11(O2)	913 Bytes	2025-8-18 11:06:57
AC	duyusen	24ms	576 KiB	C++11(O2)	860 Bytes	2025-8-18 10:51:20