Hi everybody.

The IndiaHacks finals will take place tomorrow (on Saturday). The contest is being organized by HackerEarth. Just after the official finals, the CF round will start (check-your-time) with almost the same problems. You can treat it as a standard CF round — there will be 5 problems in each of 2 divisions, and 2 hours to solve them. Two divisions will compete together on the problem set with 7 problems, with 2 hours to solve them.

I want to especially thank I_love_Tanya_Romanova for testing the problems, GlebsHP for help with making the CF round possible, and MikeMirzayanov for his awesome attitude and for the Polygon system. Setters: Lewin, k790alex, Sokolov, Errichto. Testers: I_love_Tanya_Romanova, Errichto. Small help: belowthebelt, raviojha2105, johnasselta, Radewoosh. And my big thanks to HackerEarth for inviting me to Bangalore, it's truly a vibrant city.

Some info only for 40 official finalists — Remember not to discuss anything until the CF round ends (so, at least 2 hours after the official contest ends). You will find all important information at link-to-the-contest. You can ask me questions by PM on CF or on HE, and I will put answers in the "Challenge Details" at the link provided. Do not use comments here because it can only confuse others. You can use some old blog about the IndiaHacks semifinals if you want to discuss something.

I wish you great fun and no frustrating bugs. Enjoy the contest.

Scoring: 500-1000-1500-2000-2500-3500-3500.

WINNERS

1. jqdai0815, the only one to solve all 7 problems!
2. JoeyWheeler
3. jcvb
4. andrew.volchek
5. ikatanic

In the official finals there were technical issues with the stack size (it was again only 8MB) and constraints in E weren't correct at the beginning. We want to fix it as much as possible, without any guessing though — we can't say how much time did you waste because of something. If you were affected then write to me PM with the description of the situation. Your time penalties will be canceled (and maybe some earlier submission will be accepted, if only the stack size didn't allow you to get AC).

Editorial is being created here.

Hey Codeforces!

The Elimination Round of the CROC 2016 Championship will take place on Friday, March 18 at 16:35 UTC. After our last round, Yang Liu (desert97), Michael Kural (pi37) and I realized that we haven't had enough, so we joined forces with Kevin Sun (ksun48) and Daniel Chiu (waterfalls) to prepare another problem set for you guys. Our contest will be for combined divisions and consist of seven problems. And although only those who pass the Qualification Round can participate officially, the round will be open to and rated for all Codeforces users. As always, we'll be taking the tractor to Bovinia for some farmland algorithmic adventures with Farmer John, Bessie and her best friend Elsie!

Before we begin, we'd like to thank GlebsHP for doing a wonderful job as contest coordinator—we'd be hopeless without you. We would also like to thank MikeMirzayanov and the Codeforces staff for creating the awesome Codeforces and Polygon platforms. And finally, we're immensely grateful to abacadaea for providing one of the problem ideas and to winger and AlexFetisov for test solving our round.

Formally, there will be two rounds on the same problem set (both rated):

• CROC 2016 — Elimination Round: for registered Championship participants who have passed the Qualification,
• CROC 2016 — Elimination Round (Rated Unofficial Edition): for all others.

To take part in the official round you have to be registered for the Championship and solve at least one problem in Qualification round. Both the elimination round and its unofficial edition will be rated. The only difference is that the top 50 participants in the official round will be invited to join the Finals in Moscow. Finalists will be responsible for organizing their trip (tickets, hotel, visas and so on). Each participant may claim reimbursement for transportation expenses not exceeding ~135 USD. Invitations should be accepted no later than March 25.

We hope you enjoy our problems and our cow-flavored text even more than you did last time! Good luck!

UPD1: System testing is delayed because we are investigating some technical issues.

UPD2: The editorial has been posted here. Thanks for participating!

UPD3: Since last ~15 minutes judging system was incorrectly configured for F in the contest "CROC 2016 — Elimination Round" (it is interesting story how it happened), you may appeal your rating change if it affected you much. If you have submitted a solution for F in last 15 minutes and you have strong arguments why incorrect verdict (WA/RE on the test 1) significantly affected your place, please write MikeMirzayanov to make your participation unrated. Sorry about the issue. You can do it before March, 19, 23:59 (UTC).

UPD4: I'd like to congratulate the winners of each round, as well as the top 50 in the Elimination Round for progressing to the CROC 2016 Championship Finals! In addition, Petr and jqdai0815 deserve a special shoutout for solving all seven problems!

CROC 2016 — Elimination Round

1. Petr
2. tourist
3. vepifanov
4. rng_58
5. I_love_Tanya_Romanova

CROC 2016 — Elimination Round (Rated Unofficial Edition)

1. jqdai0815
2. anta
3. Alex_2oo8
4. NaiveNaive
5. eddy1021

The Qualification Round of the "CROC 2016" Championship will start on March, 16, 09:00 (UTC).

Please, read about the Championship by the link http://codeforces.net/blog/entry/43229

You need to participate in the Qualification Round to make it to Round 1. All contestants who gain a positive score will advance to the Round 1.

At the Qualification Round you will find a few problems, roughly ordered by the increasing complexity. During the Qualification Round the problems are judged only on pretests and system testing will take place after the end of the Qualification Round (round continues for 48 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The Qualification Round has no hacks or decreasing values of the problems.

The round will last for 48 hours, but it does not mean that we encourage you to spend all this time solving of problems. We hope that most participants will cope with the problems (or with most problems) in a shorter period of time. This duration of the round is chosen so that each participant could find a convenient time to participate. The problems will be in English as well as in Russian.

Before the end of the round it is strictly forbidden to publish the problem statements/solutions/any thoughts and ideas about them elsewhere. It is forbidden to talk about the problems, discuss the statements and so on. Be honest and let the best participants make it into Round 1. When the Qualification Round is over, you can discuss the problems and solutions.

You can register for the round at any time up to its end.

The results of the round will not affect the rating. If you are not registered to the Championship officially, you can take part in the round out-of-championship.

Best of luck and enjoy solving the problems!

The final testing of VeeRoute Marathon is completed, the results are final. Congratulations to the winners!

I place, score: 488260.182 — Psyho

II place, score: 465947.075 — Rafbill

III place, score: 455743.464 — T1024

All of them will get their well-deserved reward. Additionally, by the organizer's decision, top 32 contestants will get a T-shirt: they are the contestants whose score is more than 300000. They represent 14 countries (Poland, France, Hungary, Belarus, Romania, Russia, Thailand, Lithuania, Hong Kong, Ukraine, Czech Republic, Sweden, Latvia and China) and used six different programming languages: C++, Java, Scala, Python, D and C#.

While the final testing took place, some of the contestants described their solutions:

• Psyho (1 place): greedy and two phases of simulated annealing;

• Rafbill (2 place): minimum cost bipartite matching: order chains and drivers;

• mugurelionut (7 place): graph on pairs (time, place) and greedy;

• LCM (19 place): greedy.

If you liked the marathon problem, we have good news: the second joint marathon is going to take place in two or three months. However, there's no reason to wait: if you are interested in a job at VeeRoute, fill the form, and the company representatives will contact you.

Speaking for myself, I'd like to thank the Codeforces platform and the company VeeRoute for the opportunity to conduct this contest.

The submission time is over for VeeRoute Marathon. Let us discuss the contest — the problem itself and related stuff — while the final testing takes place. Which solutions work best? Were the problem statement and materials sufficient to start solving, or something was lacking? What tools did you implement yourself?

Hi everybody!

Glad to tell you that tomorrow on 9:05 UTC there will be Codeforces Round #345. The round is formed of the first day of X Moscow Open Olympiad problemset with several additional problems created for this round. This round is brought to you by the scientific committee of Moscow Programming Olympiads controlled by GlebsHP, romanandreev and your humble servant, and also with a great help of fcspartakm who helped us make a complete problemset of our problems.

The round will be conducted under the standard Codeforces rules, you will be given 5 problems for 2 hours. Yes, this round is rated :)

Note that because of holding the main onsite round system testing and upsolving will be available no earlier than 12:35 UTC. Also we would like to ask you to not discuss problems in comments during the time between the end of the round and the end of the onsite competition. All comments with discussions will be removed and the most active violators will be punished. Thanks for your understanding.

UPD Sorry, the round start was moved to 9:25 UTC. It is not easy to run onsite round and Codeforces Round simultaneously!

UPD2 You may discuss the solutions! System testing will be run shortly.

UPD3 The editorial has finally appeared: http://codeforces.net/blog/entry/43677 Sorry for the delay!

Hello, Codeforces!

We are glad to invite all of you to test out our new Online Judge platform at csacademy.com. We're a Romanian based start-up that focuses on online education. Up until this point we've been working on creating a new environment for competitive programming contests.

Our first beta round took place in January and it was an IOI-style contest of medium difficulty. You can have fun solving the problems in our archive. Pay attention though, it is necessary to have an account in order to solve any problems on our website. You can connect via Facebook or Google+, or you can simply create a new account by providing a valid email address. Once you have an account you can choose a username, but all Codeforces handles are already reserved (so no tourist for the locals :D). We have created for you the possibility of connecting your Codeforces user here. Once connected, your Codeforces handle becomes available, otherwise it stays reserved for an indefinite amount of time.

Our second beta round will take place on Friday, Mar/04/2016 17:00 (UTC). If you want to take part in this round you need to register before the contest begins. Just like the previous round, the difficulty will be moderate (similar to a Codeforces Div. 2). You will have to solve 6 problems in 2 hours and 30 minutes.

This time around the format of the round will be different:

• There will be full feedback throughout the entire contest.
• Tasks will not have partial scoring, so you need to pass all test cases for a solution to count (ACM-ICPC-style).
• Tasks will have dynamic score. According to the number of users that solve a problem the score will vary between 100 and 1000.
• Besides the score, each user will also get a penalty that is going to be used as a tiebreaker. The penalty is computed taking into account the minute of the last accepted problem and the number of wrong submissions (only submissions for accepted tasks count).

More about our platform:

• For the best user experience we recommend using Google Chrome. We are still in beta and we didn't have time to check if everything works on other browsers.
• We currently support C++14, Java8, Python2 and Python3. We recommend using only C++ and Java for a contest, as the time limits are not calibrated for Python.
• We have a pretty cool online editor. We use it ourselves, so give it a try ;)

If you find any bugs please email us at [email protected]

People currently involved with CS Academy include:

• Mikester
• AndreiNet
• alex.velea
• Kira96
• gheorghemihai
• wefgef
• mihaic
• vladb

Don't forget to like us on Facebook, VK and follow us on Twitter.

EDIT: The editorial is ready. Congratulations to all the users and we hope you had a great time. Beta round 3 is around the corner, keep your fingers crossed!

EDIT2: We're hosting Beta Round #3.