Hello!

Yesterday I got to the Hollywood (not in California, but in Florida). Then I came out from airport, I felt hot, humid air. Not forgotten feeling from the ACM-ICPC finals tried to fool my brain, that I was not leaving Florida.

I was flying with Misha Kever (which the handle here?). Artem Rakhov (RAD) appeared when I was asleep. It seems that he has arrived together with Sergey Rogulenko(SergeyRogulenko).

It turned out that the rainy season is not over. So here “cloudy, possible rain." I did not like the ocean — very warm, quite without the waves, it is necessary to overcome large distance to swim on depth.

By the way, I’m in the room #1760. It will be good to see in comments rooms of other finalists.

As they say, to be continued ...

Hi!

I regret to inform you that the Codeforces Beta Round #88 is rescheduled for September, 23 (Friday), 15:00 (UTC). The main reason lies in me — because of trip to TopCoder Open, I must leave Saratov, and I can't make the round being in a train, in the middle ofendless Russian steppes.

I hope that the new schedule will be comfortable for some of you, and other will try to adjust plans to the schedule.

Hi everybody!

Okay, we've got good news and bad news. What do I start with? Okay, let's start with the bad news to finish more optimistically.

As I was removing the results of some recent vandalism acts (i.e. contribution cheating), I also accidentally removed the results of all your votes :(. I am really sorry and this situation is very unpleasant to me too. We've managed to restore most votes from the backups but the last month has been lost for good. Let me offer my deepest apologies for the incident. I've manually returned the rating to the main page posts, but the votes for other posts and commentaries of the last months have dropped to zero. To soothe the damage somehow, I can stress the popular notion that we are all here to solve problems and discuss the programming and the contribution is not nearly as important.

Yet every cloud has a silver lining: the incident has already inspired me to fix the daily backup system which had been malfunctioning ever since the infrastructure moved to the new server. By the way, the back-ups transfer every night to the VK data centre (our special thanks toVK) — so I'm not that afraid even of a nuclear bomb hitting the Saratov SU server room.

Besides, I guess it's high time we put effort into fight with spammers, bots and other vandals. The directions to work in have been voiced by the community members — we can limit the unrated members' actions, introduce captcha here and there, maybe there'll be something else.

Let me offer apologies once more, I hope I'll never ever re-live the emotions I experienced today. Just in case let me remind you that there is a beta letter in the logo not without a reason.

Now then, let me proudly present to you some small innovations.

• Direct links to the submission. They are of the following form http://codeforces.com/contest/contestId/submission/submissionId and are available though a submission pop-up window (cluck the # symbol in the title).
• We've introduced special Codeforces tags in posts/comments.

All tags possess the form [[tagName:param1,param2,...,paramN]], the square brackets are replaced by round ones in the examples below so that our innovations don't process the examples. Of course, when you use tags you should use square brackets. Now then, the details about the possible tags are as follows.

• Write ((user:handle)) to add a link to the user profile. The link gets bound to the current date so that the user has the color and rank valid at the moment of publication. For example, you can write the following in a comment "((user:Petr)) is number one in the Codeforces rating".
• Use ((contest:contestId)) to add a link to a contest. Such tag is displayed as a contest name but alternative contest is also acceptable. Try writing "I took part in the contest ((contest:115))" and also "I took part in the ((contest:115, contest))".
• A link to contest results is pasted similarly: "the results are available via link ((standings:115))" and "the results are available via the ((standings:115,link))".
• You can paste a link to problem (via the problem's code). E.g., "How to solve problem ((problem:115B))" or "how to solve ((problem:115B, this problem))".
• And at last, you can past a direct link to submission. The examples are "here's the submission link: ((submission:700734))" or "here's ((submission:700734, the problem submission link))".

Of course one should copy carefully when writing a tag as the copied HTML styles can interfere with the tag's contest. And finally, let us demonstrate some examples in action:

• Petr is number one in Codeforces rating
• Thanks to dolphinigle for Codeforces Beta Round 87 (Div. 1 Only) and Codeforces Beta Round 87 (Div. 2 Only)
• The results of the recent contest are available via this link
• 704386 — a short solution to the problem 115B - Lawnmower

That's the news for today,
MikeMirzayanov

As some of you have already noticed, we are introducing the innovation &mdash a virtual contest system. I guess this term was invented as far back as in 2002, as we were working on the site http://acm.sgu.ru/. Besides we were the first ones to come up with and carry out the interesting idea: enable the users to run the past contests in a special mode that would imitate a real competition. It feels just like a real contest with real contestants competing alongside with the participant who writes a virtual contest.

The idea was a success and it was picked up by some online judges. Although frankly speaking, those ideas haven't been carried out by the many.

And now it's time to introduce the virtual contest system to Codeforces! Of course, the original Codeforces rules aren't easily converted to virtual form. That's why all past Codeforces contests will be available as virtual contests by ACM-ICPC rules. In light of oncoming ACM-ICPC subregional and regional contests it can be regarded as yet another opportunity to train.

Virtual contests are available to individuals as well as to teams. If you participate as a team, please make sure that the registered team represents all your team members and nobody else. If it is not the case, change it. So far there's only one contest available for alpha-testing: it's Codeforces Beta Round #76 (Div. 2 Only), but you won't have to wait much - soon all contests will be available in this mode. Now all the past contests are available as virtual contests.

When you take part in virtual contests please follow those simple rules:

• don't participate if you've already seen the tasks;
• don't participate if you only want to commit one problem or if you don't want/can't participate in the whole contest;
• during the contest don't read tutorials, don't use somebody else's code, don't talk to other people;
• try to make it an efficient and enjoyable training!

I expect some of you to write the offered contest virtually and share your impressions. For example, JKeeJ1e30 has already participated!

I hope you like the new opportunities. We'll add something, too, to give the system final flourish, but in any way we're waiting for your commentaries rich in interesting ideas and suggestions.

The first information letter

General information

From 1nd to 11th August 2011 Saratov State University runs an international student summer school in computer programming. Teams of three people and individual participants are invited to take part in it.

The school will take place in a picturesque place at one of Saratov resort centers on the Volga bank. The participants will be provided comfortable rooms for 2-4 people and meals three times a day. The resort center owns a beach and sport grounds.

It will be 10 training days. The school includes lectures by Saratov state university coaches, joint trainings, problems tutorials and topical workshops. The curriculum is designed for younger university students who aspire to achieve high results at programming competitions. Official language — Russian.

The fees are 16000 RUR (~ 570 USD) for a person. Moreover, each team or an individual participant should bring a laptop with the support of WI-FI.

All interested participants and teams should register at http://acm.sgu.ru/sazanka-2011/ till 20th June 2011. Don't postpone the registration, as the number of participants we can take is limited.

You can get additional information by e-mail mirzayanovmr[symbol-at]gmail.com. As since the official language of the school is Russian, the registration requires knowledge of Russian. Also it is recommended to view this page in Russian.

About Saratov State University

Saratov State University, regularly achieves significant advances in programming competitions. The following are the main achievements of the university in international competitions:

• 2002 ACM-ICPC World Finals silver medals, Europian Champions
• 2003 ACM-ICPC World Finals silver medals
• 2006 ACM-ICPC World Finals golden medals, Europian Champions, World Champions
• 2007 ACM-ICPC World Finals silver medals
• 2009 ACM-ICPC World Finals golden medals
• 2010 ACM-ICPC World Finals silver medals
• 2011 ACM-ICPC World Finals silver medals

Hello!

I remind you that tomorrow will be ACM-ICPC World Finals Contest which will begin at 13:00 (UTC). The live results probably will be available by the links: http://zibada.ru/finals/ or http://icpc.baylor.edu/.

Watch! Ail! Share your impressions!

On May, 25 in the evening we attended a dinner show called "Treasure Tavern". Dinner combined with show is a rather popular entertainment format here. There were several variants and we chose this as the least childish one. In fact, the show combined elements of a stand-up comedy, a musical and a circus. It all was spiced up with the entourage of a kind of a cabaret tavern with waitresses in short dresses. However, apart from a dosen of vulgar jokes the tavern theme didn't develop. During the show we didn't understand lots of stuff, but the artists' performance was on the top level. We were impressed by a dancing couple, where the woman was sometimes hidden for literally a second behind a special curtain and the next moment she appeared in a new garment. The gymnasts' performance was also on the top level. We weren't particularly impressed by the food, but on the plus side, it was the first time I've tasted meat with blood and I liked it. On our way home Artem even went to Burger King (I understand him).

The performers tried to make a superstar out of Kolya but he refused

The train number nine from Saratov to Moscow was a pleasant surprise. Every compartment in our wagon had a small TV, outlets, and each passenger could use a personal safe with a code lock. Of course, we didn't turn the TV on and didn't use the safes. Imagine how ironic it would be if we put there, say, a passport and forgot the code number.

Note that there's not only a TV, but also also outlets behind Nickolay.

In Moscow we had a little snack in some seedy railway eatery (in fact, Kolya and Artem went to Mcdonalds) and got on an express to the Domodedovo Airport. The fun lasted 40 minutes and cost 12 USD rubles each. Russian Railways have a good business!

Today Saratov delegation will go to the championship's finals. As you remember, we've been planning to go to Sharm El-Sheikh since January, watching their great February revolution anxiously. As a result, the finals were moved to Orlando (Florida, USA). Our delegation got a little smaller too, as May is a hot month and it's a long way from Russia to the USA.

Our team is famous on Codeforces. And that's not surprising! Just look at them:

• Maxim Ivanov (e-maxx) spends considerable time among the top rated users and among the top contributors. Many know his wonderful site http://e-maxx.ru/, of course. Attentive users recognize him as a determined bug filer in gcc issue tracker and an author of some contests. Maxim is on the fifth year in SSU Mechanics and Mathematics Department and his interests include "programming, programming and... oh yeah, programming :), zen, taoism, philosophy, psychology, the bike".
• Artem Rakhov (RAD) is known as the Codeforces problems' coordinator, the participant of all on-site prestigious competitions (TopCoder Open, Google Code Jam, Faceboook Hacker Cup) and a great Cola fan. Personally, I've known Artem since the eight year at school and I shudder to think how many problems he has solved since then :)
• Nikolay Kuznetsov (NALP) is known as the author of several rounds and the one who fights ardently for clear statements. He used to be in one team with Artem back at school days. I remember how surprised I was when I learned that he got to TopCoder High School Competition. Nikolay is a third-year student of the Department of Computer Science and Informational Technologies of SSU and he is my student. On July, 10 I exam him on the theoretical course in Programming Methods. By the way, Kolya, let me remind you that you haven't yet got the pass for the practical work!

Besides, the team has me as the coach and Antonina Fedorova as the team leader.

I will do my best to keep you up to date on how the trip's going (mostly on the actual finals, of course). However:

I urge the participants of the event not to keep their interesting impressions hidden and bottled up. I want you to share them. For example, you can publish them on Codeforces!

As a conclusion to the entry, I want to ask a question to those who have already planned the whole trip. As far as I understand, the couple of days before the finals in Orlando won't be spent uselessly: there are some grand amusement parks around. I've got a question to those who are prepared and to those who are keen on that: which place will be most interesting for the ACM-ICPC team? As far as I understand, the tickets to those parks are not exactly cheap, but in one can get a discount now and then - how should we purchase the tickets?

Just in case I inform the Saratov residents that we leave today, on May 23, on train 9.

Hello.

This round will start Yandex.Algorithm 2011. The problems of the round were prepared by me, of course, with the help of the Codeforces team and Yandex.

I hope you enjoy the problems and their solution will start a successful performance at the tournament.

As you have already noticed — the system operates in a somewhat truncated form. We decided to run it in safe mode and turn off some functionality at the time of the contest. After the round everything will be back.

I recall that the top 500 participants will receive a ticket to the first online round of the Yandex.Algorithm. However, if you do not get to qualify at this time, do not despair — you can participate in the second qualification, which will be held on May 6 at 15:00 (UTC).

I wish you have a fun,
MikeMirzayanov

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 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.

Last night I don’t want to sleep, so – I was working. I reread my old post "Contribution 2.0" (in Russian) and decided to implement some ideas. Taking into account the comments that everyone (no matter the color nor the position in the contribution) has the right to express their opinions in the form of pluses or minuses, I did not restrict users the opportunity to express opinion.

On the other hand, the rules of contribution changing depending on your votes have modified. Since we have already appeared bots, trolls and other vermin, I will not reveal details, but note that:

• Contribution may change after some time after the processing of your vote - it is normal.
• Not all your votes may be taken into account when calculating the contribution changing - this is also normal, we will defend ourselves from dirty tricks.
• contribution slightly scaled - the numbers got bigger. Maybe it's nicer?

Just want to say that the bots usage, following the principles of "blood feuds," etc. serve as a reason for your disqualification. Do not tempt fate.

Soon, the problems coordinator, the user RAD will leave official lists of both contributions and rated, as he is active member of the Codeforces team.

I wish you high contribution
MikeMirzayanov

We are delighted to inform you that Codeforces has collaborated with CodeFest'11, the annual international online coding festival of Computer Engineering Society, IT-BHU. CodeFest is a unique fest wherein concepts of mathematics, logic, artificial intelligence, algorithms, language syntax, etc. are required to be deployed in programming; these concepts manifest themselves in solving problems effectively and efficiently!

Codeforces is the programming partner of CodeFest'11. In fact, Manthan:, which is the algorithm intensive programming contest being organised by CodeFest will be hosted on Codeforces.

• Mathmania: A mathematical puzzle contest inspired by Project Euler. Main event to be held on 27th Feb, 2200 hours IST. Prizes worth 30,000 INR to be won.
• Manthan: An algorithm intensive programming contest. It is a Google sponsered event with Prizes worth 50,000 INR Event to be held on 13th March, 2200 hours IST. Registrations are on!
• Perplexed!: Constraints based C programming contest. Event to be held on 11th March, 1800 hours IST. Prizes worth 30,000 INR to be won.
• Virtual Combat: An educational game of robotic tank. Watch this out. Phase - 1 submission deadline - 7th March. Prizes worth 35,000 INR.

More than 2500 programmers from 59 countries have already registered for CodeFest'11. Come and be a part of the biggest coding extravaganza in Asia.

Feel free to contact us at [email protected] or reach us personally at:

• Mohit Bansal [email protected] (+91-930-505-3020)
• Saket Saurabh [email protected] (+91-945-282-5690)

Be free and Happy coding,
CodeFest and Codeforces team