In the discussion at http://codeforces.ru/blog/entry/6870#comment-125383 it became apparent that Jacob has submitted a solution for Round 172 Problem E that passed all system tests, and was not challenged, but in the end he didn't get the score for it because a tester has decided to stress-test it against a correct solution and add tests where it fails to the system test.
I think this is an awful, awful decision, as it goes against the spirit of progamming competitions: automatic judging and complete objectivity it gives.
There are so many ways this can discriminate against Jacob:
Had I submitted a solution for problem E, the tester might not suspect it would be a wrong greedy (because I'm in top 10 by rating) and would not add tests, and I'd get the points.
Maybe some people who opted for solving problem D instead also submitted wrong solutions, but since there were more than one of them, the testers did not think to stress-test them.
Had he submitted his solution right before the end of the contest, the tester might not decide to read it because he'd have other things to do.
But these points are minor compared to the main point, which I want to reiterate:
- This breaks everyone's faith that the competition is fair and objective. The beauty and appeal of programming competitions, in my opinion, relies on this one aspect: automatic judging. Please don't take it away from us.
In this particular situation, I propose to remove the tests in question and give Jacob the score for this problem. In the future, I propose to keep to the formal procedure — use the tests prepared before the contest plus successful hacks. This is the only way to make sure the competition is not subjective.
I don't blame the particular author or tester for this problem — I actually applaud them for bringing this problem to light and explaining their actions clearly. Thanks a lot! Hopefully we can learn from this situation and avoid similar issues in the future.