Hello!

As you have already noticed the menu will link to the results of the competition has appeared. Drum roll, fanfare, applause, and the blinding spotlight! We congratulate the winners:

• Winner is Aleksey, 33 score points!
• The second place — mrButt, 30 points
• The third place — Sanya_M, 29 points
• The fourth place — Ruslan, 25 points
• The fifth place — MaxBuzz, 24 points

Congratulations to all winners! Note that the program by Aleksey has surpassed all expectations of the jury erred solely on hard-to-recognize archives.

I'm asking all winners to send me a private message, we have something to discuss.

MikeMirzayanov

UPD: One test has been found in which the author's answer was incorrect. I've rejudged solutions, but the order of participants has not changed :)

The round duration is increased to 2 hours and 30 minutes.

Hello!

As many of you have noticed we have new features on Codeforces. The tab “Friends” has appeared on the user ratings page. But it is only the first of improvements made. Now you can view a list of friends on problemset standings, contest registrants and contribution standings pages. Because of increasing popularity of Codeforces the pagination has been added to the rating page.

But that's not all. In order to classify problems, it was decided to introduce the ability to add tags to them. Search by tags is not implemented yet, but administrators and users with high (your color should be at least blue) rating can add tags right now. To do this, simply open the desired problem and add tags in the sidebar form.

As you can see, the project development is actively underway. We would like to hear from you new constructive suggestions. 

Updated:

In the near future will be implemented a compact view of tags in the problemset and a setting to show/hide tags.

Maxim Shipko, Codeforces Team

The coding phase has been finished. Please wait for the final testing and results.

Good day everybody.

Everything written below is not a April Fool's joke. Though it is also a funny occasion :)

We are glad to announce a new experimental contest on Codeforces, "Problem Parser Contest".

Have you ever made training sessions, using the previous contests' archives? Have you downloaded from the Internet contest archives to test for your solutions locally? If the answer is 'yes', then you couldn't help noticing that each organizer insists upon inventing his own way (format) to distribute problems. Yes, it is true!

I've prepared and organized a huge number of trainings based on the previous contests. It is often rather a monotonous task; one often has to write some scripts that rename the input/output files of the problem into the standard form. In archives they are called very differently: they can be river.in.1, river.out.1, river.in.2, river.out.2, etc. In another problem they can be tests/1.dat, tests/1.ans, tests/2.dat, tests/2.ans etc.

At some point I got fed up with it and wrote a script that told the patterns of paths to the test files, using some heuristics and the regularity I'd noticed. The script worked well, but it wasn't perfect.

Unusual tournament Manthan 2011 showed the weaknesses of the current rating formulas. After the end of contest the winner of the competition tourist has expected rating change equal to "-1":)

This has arisen due to reduction of the calculated changes in such a way, that total sum is equal to 0. That is, Gennady was in some pros before such changes, but as the sum of all the changes turned out to be positive, then all the ratings were a little reduced. As a quick dirty hack in the round I turned off this feature, leading to a one-time inflation. Even a small mistake: I noticed that participants in the second division get too many points after a good performance on "Div. 2 Only" rounds.