Sometimes wrong solutions or get Accepted, being found wrong after months.
Sometimes the original tests are too weak that brute force passed.
I Think Codeforces should support Hacking even after the contest(while rating changes may not be modified).
What about that?
I think it would make Standings much more confusing. And people who were beaten by users with fake solutions would be mad at the author. It is also impossible to make system test which break every solution so there would be much more hacks over time.
I know it cost too much. But some OJs in China have supported this(They do not or just partially rejudge the old submissions to avoid the huge rejudge cost).
I think if you know a program is wrong but it displays AC, it would be worse.
Well, there are problems, such as "fake Hack" and Hack on Hashes.
It is worse, but most of the time you don't know about it.
It is worse, because most of the time you don't know about it.
It is worse, since sometimes I do know about it but I can do nothing.
Well, just an advice. (Most likely, it won't become true I guess
I think it is difficult as you can imagine the amount of rating changes that would occur because of this.
Well, I said maybe we can only judge the newest submissions with the Hack test cases, do not rejudge or paritially rejudge the old ones and keep rating unchanged.
;0