Hi guys!

Glad to invite you to Codeforces Round #599 to be held this Nov/06/2019 18:05 (Moscow time)!

My name is Evgeny Vihrov, this is already my 6th Codeforces contest as an author. To introduce myself, I have participated twice in the ACM ICPC Finals (2012, 2014) and currently I am co-coaching teams for the ICPC at the University of Latvia. This is my first solo round, and it took 3.5 years to make! (the last one was #347 with Alex_2oo8).

In this contest you will have to help Ujan deal with his renovation issues. Hopefully, everyone will find a problem matching their taste!

Huge thanks to arsijo for coordinating the preparation of the contest and for the patience with the frequent delays. :) Thanks to Xellos, Origenes, KAN and _overrated_ for generously testing the round. And as always, thanks to MikeMirzayanov for the panem et circenses Codeforces and Polygon systems!

Wish you an exciting round!

UPD1: McDic is joining as a coauthor of the contest (reasons to be revealed later)!

UPD2: Scoring:

Div. 1: 500-1000-1500-2000-2500

Div. 2: 500-500-750-1500-2000-2500

UPD3: Thanks for participating! Congratulations to the winners!!!

Div. 1:

1. Benq
2. jqdai0815
3. ecnerwala
4. AndreySergunin
5. tribute_to_Ukraine_2022

Div. 2:

1. hakobdilif
2. is1813r
3. Fype
4. KenMuse
5. tdas

UPD4: The editorial will be available tomorrow, sorry for the delay. :((

UPD5: The reason behind McDic entering as a coauthor is that one problem was exactly identical to some problem from some Codeforces round. We found out about it only at the last day before the contest, and McDic generously allowed to use his problem.

UPD6: Editorial is posted.

The MEX Foundation Contest #1 (supported by AIM Tech) that was held in the 37th Petrozavodsk Programming Camp now available in the Gym.

The authors of the contest are Jatana, cookiedoth, kiyotaka. The problems are of a good quality, a number of participants can approve it.

Special thanks to vintage_Vlad_Makeev for useful advices, LHiC for testing the contest, vintage_Vlad_Makeev for inspiration and AIM Tech Members for the problem review.

UPD: The editorial is published!

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Hello! Codeforces Round 598 (Div. 3) will start at Nov/04/2019 16:15 (Moscow time). You will be offered 6 or 7 problems (or 8) with expected difficulties to compose an interesting competition for participants with ratings up to 1600. However, all of you who wish to take part and have rating 1600 or higher, can register for the round unofficially.

The round will be hosted by rules of educational rounds (extended ACM-ICPC). Thus, during the round, solutions will be judged on preliminary tests, and after the round it will be a 12-hour phase of open hacks. I tried to make strong tests — just like you will be upset if many solutions fail after the contest is over.

You will be given 6 or 7 (or 8) problems and 2 hours to solve them.

Note that the penalty for the wrong submission in this round (and the following Div. 3 rounds) is 10 minutes.

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behavior. To qualify as a trusted participants of the third division, you must:

• take part in at least two rated rounds (and solve at least one problem in each of them),
• do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

Thanks to MikeMirzayanov for the platform, help with ideas for problems and for coordination of my work. Thanks to my good friends Daria nooinenoojno Stepanova, Mikhail awoo Piklyaev, Maksim Neon Mescheryakov and Ivan BledDest Androsov for help in round preparation and testing the round.

Good luck!

I also would like to say that participants who will submit wrong solutions on purpose and hack them afterwards (example) will not be shown in the hacking leaders table.

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Good day, Codeforces! Or in my language, magandang araw, Codeforces!

Codeforces Round 597 (Div. 2) will be held on Nov/01/2019 17:35 (Moscow time). Is it rated? Yes, but only for participants below 2100 rating.

Of course, this round is not made by me alone. So, I would like to thank the following people for their help in making this round possible:

• coordinator awoo, for coordinating my round even when he was very busy;
• testers antontrygubO_o, McDic, 300iq, adedalic, isaf27, farmersrice, 265918, vovuh, CaseRuten,Stresshoover, nooinenoojno, Pavlova, defolaut, and Arpa, for testing problems and giving very valuable feedback;
• and of course, MikeMirzayanov and Codeforces staff, for providing us with the amazing Codeforces and Polygon platforms!

There will be 6 problems, and you will be given 2 hours to solve them.

The scoring distribution is as follows: 750-750-1250-1750-2250-2500.

I hope you enjoy the round!

Update: editorial is out now

Hello, Codeforces!

The China Collegiate Programming Contest (CCPC) is a competitive programming contest series for college students in China, organized by the CCPC Committee, which consists of coaches of the competitive programming teams of Chinese universities. It started in 2015, and this year is the 5th edition of CCPC. There are 4 onsite CCPC contests this year, including three regional contests in Qinhuangdao, Harbin and Xiamen, as well as the CCPC Final in Beijing. Many Chinese universities use CCPC as an opportunity to practice before the ICPC regionals.

The 2019 CCPC Harbin Site has recently ended on October 13 in Northeast Forestry University. A total of 272 teams, most of whom were selected from the preliminary online contest, took part in the official onsite contest in Harbin. The problems for this contest were mostly prepared by retired ICPC participants of Zhejiang University, and the head judge was me.

We are glad to invite you to participate in its online mirror: The 2019 China Collegiate Programming Contest Harbin Site in Codeforces::Gym! Please note that the mirror contest will start at Saturday, November 2, 2019, 18:00 (UTC+8). Click on the link to see when it starts in your timezone. We will be able to answer your questions during the mirror contest. The ghosts of the onsite participants are available, so you may take advantage of it.

This contest uses ACM-ICPC rules and of course, it is unrated. Team participation is recommended, but it is also possible to participate individually. As usual for Gym contests, you may register for this contest 6 hours before it starts, and you will be able to virtually participate and upsolve the problems after it ends.

My thanks go to:

• Volunteers and staff from Northeast Forestry University for holding a very successful onsite contest.

• Problem authors: lsmll, quailty, Claris, jiangshibiao, shb123 and reku.

• Testers: izban, 300iq, and many members of the competitive programming team of Zhejiang University, some of them are: Todobe, wxx_louisa, zx2017, SoSad, zhangqingqi and lyk248289469.

• MikeMirzayanov for the powerful Polygon and Codeforces system.

• The CCPC Committee and the sponsors of the onsite contest.

We kindly ask everyone who has already know the problems not to participate or discuss them before the mirror contest has ended. Hope you enjoy the problems!

UPD: Contest has ended, thanks everyone for your participation. Here is the link to the official editorial, unfortunately it is in Chinese. But feel free to ask in the comments if you have any questions about the problems.

Hello!

ICPC Southern and Volga Russian Regional Contest (Northern Eurasia) 2019 has ended on October 15. There were 76 teams onsite in Saratov, most of them were invited because of their result on the qualification stage.

On Oct/27/2019 12:35 (Moscow time) will start online-mirror 2019-2020 ICPC, NERC, Southern and Volga Russian Regional Contest (Online Mirror, ICPC Rules, Teams Preferred).

In this contest I play a role of Cheif Judge and the jury teams consists of ex-participants of ICPC from Saratov and jury members from other cities. Many thanks to all of them! I hope you will like the problems!

I invite ICPC teams and individual participants of Codeforces competitions to take part! Sure, the contest will be unrated.

— MikeMirzayanov

Hi,

We would like to invite you to participate in the live (with 30-minute delay) online mirror contest of The 2019 ICPC Asia Jakarta Regional Contest (our regional website, our regional in ICPC website, official contest portal) this weekend. The online mirror contest will start on Oct/27/2019 06:30 (Moscow time).

The contest consists of several problems and you can solve them in 5 hours.

See you on top of the leaderboard.

UPD1: Thanks for participating. The problems should be available for upsolving. The soft-copy of the problem analysis (the same as the one distributed to all contestants during the awarding ceremony) is available here.

UPD2: The full problem repository is available here. The full problem repository for Indonesia National Contest (INC) 2019, which is the national programming contest that serves as the online preliminary round for Indonesian teams to advance to The 2019 ICPC Asia Jakarta Regional Contest, is also available here. The problems are also available for upsolving in TLX (INC and ICPC)

We are aware about the issues with rating in Division 2. MikeMirzayanov is on it and will fix everything soon.

Congrats to the winners!

Technocup edition:

1. cookiedoth
2. MaksymOboznyi
3. AlFlen
4. talant
5. DANDROZAVR

Div. 1 round:

1. Benq
2. jqdai0815
3. tourist
4. Um_nik
5. TLE

Div. 2 round:

1. BBumblebee
2. twytch19
3. zhongyuwei
4. kpink
5. 1LLUS0RY

Analysis can be found here (if it doesn't show the analysis, just wait for a little bit).

Scoring distribution:

elimination round: 500-750+750-1500-2000-2750-3250-3750

division 2: 500-750+750-1500-2000-2750-3250

division 1: 500-1000-1750-2250-2750-3250Hi Codeforces!

This weekend, on Oct/26/2019 14:05 (Moscow time) we will hold Codeforces Round 596. It is based on problems of Technocup 2020 Elimination Round 2 that will be held at the same time.

Technocup is a major olympiad for Russian-speaking high-school students, so if you fit into this category, please register at Technocup 2020 website and take part in the Elimination Round 2.

Div. 1 and Div.2 editions are open and rated for everyone. As usual the statements will be provided in English and in Russian. Register and enjoy the contests!

Have fun!

Hello Codeforces!

On Oct/24/2019 18:05 (Moscow time) Educational Codeforces Round 75 (Rated for Div. 2) will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

This round will be rated for the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 7 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, Adilbek adedalic Dalabaev, Vladimir vovuh Petrov, Ivan BledDest Androsov, Maksim Neon Mescheryakov and me. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

Our friends at Harbour.Space also have a message for you:

Hello Codeforces,

We would like to invite all of you to Mike Mirzayanov's course Advanced Algorithms and Data Structures, which will take place in Barcelona, from the 6th to 24th of January, 2020.

The course will consist of three weeks of training, 5 training days each week. The program includes daily lectures and practical exercises. It will be quite educational, insightful and entertaining!

And you will have the opportunity to meet and talk with Mike, who will be happy to share his knowledge and stories about the history of Codeforces.

We are happy to offer a special price of 1,000 EUR* for all Codeforces users.

Register on the page below and we will contact you for the next steps. Hurry up! Only 10 spots available.

* The cost does not include travel or accommodation.

We would also like to recommend you an article published on our blog last week about the 5 reasons why traditional universities can’t keep up with humanity.

UPD: The start of the round is postponed by 30 minutes.

Congratulations to the winners:

96 successful hacks and 196 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

UPD: Editorial is out