Hello, Codeforces!

I'm quite excited to invite you to participate in Codeforces Round #447 (Div.2 Only) which will be held on November 19 16:55 MSK.

All five problems are created by Zerui Cheng (Marco_L_T), Bingheng Jiang (NOIRP), Yiming Feng (whfym). And it's our first round on Codeforces. We want to show our great thanks to our school The High School Affiliated to Anhui Normal University and our coach Guoping Ye in competitive programming training.

And we also want to show our great appreciation to Mikhail Krivonosov (mike_live), Gleb Lobanov (Glebodin), Weihao Zhu (Tommyr7), Shiqing Lyu (cyand1317) for testing the problems, to Nikolay Kalinin (KAN) for coordination and to Mike Mirzayanov (MikeMirzayanov) for the fantastic Codeforces and Polygon platforms. The round can't be realized without their great help.

The contest will consist of 5 problems and you'll be given 2 hours to solve them. As usual, the scoring will be announced shortly before the start of the contest.

The contest is rated for Div. 2 contestants. And the same as before, Div. 1 contestants can take part out of competition.

Wish everyone high rating and bugless code!

See you on the leaderboard!

Clarification: In the mail, it reads that the duration is 2 hours and 30 minutes and it'll contain 6 problems. There's a mistake. The duration of the contest is 2 hours and there will be 5 problems.

UPD1: Scoring: 500-1000-1500-2000-2500

UPD2: The contest is finished! Have fun hacking!

UPD3: The system test is finished! Congrats to the winners!

And do you find something interesting in the statements,especailly for Chinese contestants?

Div.1 & Div.2:

1. fateice_ak_ioi (solved all the problems and got 22 hacks)

2. peace (solved all the problems and got 10 hacks)

3. dreamoon_love_AA

4. KrK (solved all the problems)

5. Benq (solved all the problems)

Div.2:

1. fateice_ak_ioi (solved all the problems and got 22 hacks)

2. peace (solved all the problems and got 10 hacks)

3. ec24 (made 16 hacks)

4. daaaaaaaaaaaaaaaaaaa

5. QYitong1

UPD4: Maybe you're complaining that there're too many hacks and the pretests are so weak,but it's our intention to do so. We regard hacks as a very important part and a feature of Codeforces.Do you agree?

UPD5: Editorial

Maybe B and C are a little harder than before,we'll be cautious about this next time.

Hope you have fun in solving the problems and hacking!

See you next time!

Hi Codeforces!

I'd like to invite you to join Codeforces Round #446 which will be held on November 17 at 17:35 MSK.

And yes it is rated.

The contest is prepared by Omid Azadi (omidazadi), Mehrdad Saberi (Batman), Arshia Soltani (ckodser), Aryan Esmailpour (Aryan) and me (I honestly didn't do anything).

And also thanks to Mahdi Amiri (Amiri), AmirReza PoorAkhavan (Arpa) for helping us, Weihao Zhu (Tommyr7) for testing the round and Nikolay Kalinin (KAN) for round coordination and Mike Mirzayanov (MikeMirzayanov) for awesome platforms Codeforces and Polygon.

You will have 2 hours and 5 problems each division.

Contest theme will be about Seven Deadly Sins but the statements will be short and brief.

The scoring distribution will be posted soon and good luck and stuff.

Update 1 : The scoring for both divisions is 500 — 1000 — 1500 — 2000 — 2500.

Update 2 : The round is over. Hope everybody had fun and enjoyed it. And as you can see the round is rated so yay!

Top 5 Div1 participants :

1.jqdai0815 (The only one who solved all problems)

2.Radewoosh

3.dotorya

4.SkyDec

5.ksun48

Top 5 Div2 participants:

1.shoob

2.mosthenio

3.SLLN

4.fdoer

5.dl1997

The editorial is posted.

Hey everyone!

Good news — Russian AI Cup 2017 has started! This competition is being held for the sixth time, and this time, hopefully, we will make happy all the fans of the RTS game genre — you will be controlling 500 vehicles of 5 different types at once. The task is to destroy the opponent!

Try yourself in creating an artificial intelligence, it's simple and fun. Go to Russian AI Cup site and enter the battle. Good luck!

The contest is declared unrated. For Technocup, results of this round will be counted for elimination. Also, we plan to hold one more (the fourth) elimination round to compensate this failure. Stay tuned for updates. We apologize for the situation, hope you enjoyed the problems.

Hello.

If you are upset about today round, I understand you. Please, downvote this blog instead of the official announcement. The coordinator, writers and tester did a great job making the round. But technical issues erased their effort.

The chain of technical issues leaded to so bad work of the website. This week our server with Polygon system had broken and Mail.Ru quckly replaced it with another one. I forgot to reconfigure Polygon on the new server and it leaded to 502 during the contest. Also today one Codeforces server stopped to respond and I do not know the reason yet (it is first time issue with this server).

Right now I feel myself very upset and thinking about the way to change an approach to have enough time to setup, monitor and develop the system.

Sorry again about it.

Hi all!

This weekend, at 16:05 UTC on November 12th, 2017 we will hold Codeforces Round 445. It is based on problems of Technocup 2018 Elimination Round 3 that will be held at the same time.

Technocup is a major olympiad for Russian-speaking high-school students, so if you fall into this category, please register at Technocup 2018 website and take part in the Elimination Round.

I want to thank MrKaStep, komendart, veschii_nevstrui, bixind, AndreySergunin and DPR-pavlin, who authored and prepared problems for Technocup, and Lewin, who kindly suggested the last problem. I also want to thank zemen and AlexFetisov for testing the round.

Div. 1 and Div.2 editions are open and rated for everyone. Register and enjoy the contests!

UPD: We apologize that we run into technical issues during the round. The round will be unrated. I hope you liked the problems.

Anyway, congratulations to winners!

Технокубок 2018 - Отборочный Раунд 3

1. potapov_al
2. 300iq
3. qoo2p5
4. Vosatorp
5. manoprenko

Codeforces Round 445 (Div. 1, based on Technocup 2018 Elimination Round 3)

1. V--o_o--V
2. Petr
3. Um_nik
4. SirShokoladina
5. LHiC

Codeforces Round 445 (Div. 2, based on Technocup 2018 Elimination Round 3)

1. mosthenio
2. Ingus
3. paulsohn
4. xX_ucfNOTpt_Xx
5. Omar_Morsi

Editorial is published.

Hello Codeforces!

On November 09, 18:05 MSK Educational Codeforces Round 32 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.

The round will be unrated for all users and will be held on extented ACM ICPC rules. After the end of the contest you will have one day 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 prepared by Mikhail awoo Piklyaev and me.

Good luck to all participants!

UPD: Editorial.

I also have a message from our partners, Harbour.Space University:

Thank you for taking part in the 2nd Hello Barcelona Programming Bootcamp in collaboration with Moscow Workshops ACM ICPC. It was a pleasure to have you on board. We hope you enjoyed it and we would love to have you back next time.

Congratulations ITMO and Harbour.Space University teams for winning divisions A and B! It was amazing watching the scoreboard throughout all nine days as teams from New South Wales, Saint Petersburg, Tokyo, among many others, challenged the top spots. Watch the recap here!

``Geometry is the key to success in modern contests'' states Andrey Stankevich, coach of 7 ACM-ICPC World Champions

Lecturing both divisions A and B, Andrey brought a vast wealth of knowledge to the boot camp, and shed light on how to better tackle the problem sets that teams will face in their upcoming regional competitions.

“What technology should we use to analyze big data?” asks Alexey Dral, Head of Data Science School at Corporate University of Sberbank

Leisure day was a full one, with bus city tours, to gaming, to lectures and workshops. We had many special guests Sberbank, including Alexey Dral, who talks about the impact of a boot camp that is not only focused on the coding aspect, but the machine learning, the data processing and the practices that each participant can utilise to become an ACM-ICPC competitor to be reckoned with.

Scholarship Information

We are offering a Scholarship for each of our three tech programmes: Data Science, Computer Science and Cyber Security — fill out the Form for the January 2018 programme start period or the September 2018 programme start period. We will contact you soon. Can't wait to see you here!

Go to form

Hi everyone!

On this Saturday I'm giving a lecture on Fast Fourier Transform on Moscow International Workshop ACM ICPC. Due to this I wrote lecture notes which anybody can use as reference for Fast Fourier Transform. I added there almost anything one should need while using FFT in contests. Even if you suppose you know the algorithm I dare you to look this paper through since there still can be some new ideas for you. Also you can see Russian version here.