In the latest Codeforces round

I gave memset_inf my solution of A

and he used it to skip

he skipped successfully, but why the system said I got zero mark ???

by the way, memset_inf said he also used xay5421's code, but xay5421 is fine.

I asked one of the round writer Sulfox for this matter, but he said he don't know why it happens.

I don't want the rating I get with my hard work disappear because of some reason I really don't understand.

hope MikeMirzayanov or somebody who knows about it could help me with it.

I will appericiate it if you could help me.