PeterASteele's blog

By PeterASteele, history, 7 years ago, In English

I greatly enjoy solving problems on codeforces in preparation for ICPC contests. The codeforces rating system is fun, and at Virginia Tech, we have a website that uses the codeforces API to rank members of our team. I say this to establish how much I enjoy training on the codeforces platform, and that I do not mean to insult Mike or the codeforces team.

At the bottom of Div1 there is a frustrating phenomenon: If a user does not submit, rating is not computed. At first thought, this seems well-intentioned. It would be quite unfortunate for a user to register and forget, and lose rank as a result. But the side effects of this are too great. The side effect is that if you do not solve problem A quickly, it is better not to submit. Over 1/3rd of the people who register take advantage of this during contest, and it is quite frustrating for low div1 members.

This effect was quite pronounced this last contest, and out of 650+ people registering, only 391 made a submit. Of those people, nearly all made a submit early on the first problem. The ELO system continues to work, but only among people who already think they have a good chance at doing well.

This last contest, 370 people out of 391 solved problem A and problem B. Only 2 people failed to solve both A and B problems. This is not because A and B were trivial; they were not (see div2 results for the same problem). As a result of so many people leaving the contest, it makes it extremely hard to maintain a rank without leaving during your own bad contests. As more people do this, it snowballs. It becomes more and more punishing NOT to leave the contest if you don't have a perfect start.

The fix is simple: Make people lose rank if they register and do not submit. Late registration has a delay for submits, but this could be increased to ~30 minutes to reduce the chances of people abusing late registration to jump in the contest if they like the first problem.

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