Seavec Not Rejudged

My submissions for the problem Seavec in the November Challenge have not been rejudged.
Submission id’s:

1.) 2961472

2.) 2961383

The above submissions generate a score of 46.016234 when submitted under the practice section.

Submission id: 2982089.

@admin kindly look into the matter asap.

3 Likes

@admin please see this
Submitted after the contest : http://www.codechef.com/viewsolution/2982159 (21.565174)
Same code during the contest : http://www.codechef.com/viewsolution/2973467 (0.000192)which is the score for 2test cases only…this clearly shows the submissions were not rejudged

There seems to be an issue with rejudging of challenge problem of November long 2013. We are looking into this. We regret the inconvenience caused.

3 Likes

My guess is that the problem lies in the scoring method and the selection of test cases and not in the rejudge. This problem failed on both fronts:

  1. Getting lucky with some random choice of elements on some small test case can give you a huge advantage while pushing everyone else to 0. And you can’t make up this difference on other test cases because I assume the score is summed over test cases and only then evaluated relative to the best sum. Instead, you should use relative scores on individual cases and use an average or sum of these relative scores as the final score.

  2. How is a secret test case generation method still an option? It has been demonstrated several times that it’s bad. I would assume that the sizes of input data would be randomly and uniformly distributed over the given range. Or will there be mostly small cases where I can score huge points? Perhaps there won’t be any small cases and I’m wasting my effort. It’s a guessing game that noone likes.

Just look at some submission that scored a huge number of points and then check the ones submitted by the same contestant just before and after. They are basically the same but give insanely different number of points, which clearly illustrates the influence of getting lucky with the random seed. The problem’s scoring method and it’s test data make this luck factor very important.

6 Likes

@admin please also look through my solution http://www.codechef.com/viewsolution/2978279 and http://www.codechef.com/viewsolution/2982256 its giving me some points in practice room but according to current status I did not get any point.

Point 2 added to the fact that only score of a small percentage of the test cases is shown turns it into a “hope for the best” type of problem.

@thocevar I never used a random function in my solution. So ideally the scores in the practice and the contest after rejudging should match, which don’t.

Interesting, then the situation is even worse than I thought.

Apparently there was an issue with the judge software that indicated the end of rejudging. The CC guys are working on it. Hopefully things will get back to normal soon. :slight_smile:

@aichemzee so by when can we expect to see the updated scores?

@thocevar: The only contestant who seems to fit your description of scoring many points and “getting lucky” is @tibip , who has a time-dependent rand seed in his best scoring submission. I resubmitted his solution in the Practice section but it keeps getting TLE (so I cannot evaluate how variable his score may be and, thus, how lucky he was). Anyway, the scoring method was known to all of us (the final score is the average score over all test cases), so we just had to make the best of the conditions we had (although I also didn’t like those conditions).

1 Like

@thunderking I have no idea. They said they would rejudge, but as it turns out, only my above mentioned two submissions have been rejudged after this post. I have like 70 odd ACed solutions still pending a rejudge. No action still.