【例70.2】求A-B字符串

Status	Submit By	Time	Memory	Language	Code	Submit At
AC	高翊宸	33ms	512 KiB	C++98	249 Bytes	2026-1-24 11:01:42
AC	fzk	33ms	568 KiB	C++17(O2)	238 Bytes	2026-1-24 10:50:09
AC	wjy	33ms	564 KiB	C++17	253 Bytes	2026-1-24 10:57:36
AC	游客	34ms	512 KiB	C++17	288 Bytes	2026-1-24 10:58:28