By MikeMirzayanov, history, 2 months ago, In English

Hello, Codeforces.

I have implemented automatic translation of problem statements in Polygon (yes, yes, through ChatGPT). Here's an example of how to use it:

  • Suppose we have a problem statement only in Russian and we want to have it in English as well.

  • Create an empty problem statement in English.

  • Go to the bottom of the problem statement and click on "Add automatic translation."

  • In the popup window, you can choose the original language for translation (we only have Russian, so there's nothing to choose) and the section of the problem statement to translate (by default, it usually selects the appropriate option — translate everything).

  • Click the "Translate" button.

  • Wait for ChatGPT to translate the text (it may take up to a couple of minutes).

  • When the translation is ready, it will be loaded into the popup window.

  • Click "Save Translation."

  • Done.

  • Remember to proofread the statement yourself. Although it's a quality machine translation, it's still a machine translation.

One useful thing to note is that this method of translation miraculously preserves most of the LaTeX markup.

When using it, remember that the API is not free. I have set quotas, and if they are exceeded, I will have to turn off the feature. I hope this doesn't happen.

There are a few more ideas on how to use ChatGPT for peaceful purposes. Don't go too far.

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By pooty, 2 months ago, In English


Hello, Codeforces community!

We are happy to invite you to participate in National University of Singapore (NUS) CS3233 Final Team Contest 2023 Mirror on Monday, April 10, 2023, at 09:35 UTC. CS3233 is a course offered by NUS to prepare students in competitive problem solving.

The contest is unofficial and will be held in Codeforces Gym. Standard ICPC rules (Unrated, ICPC Rules, Teams Preferred) apply. The contest is unrated. Note the unusual starting time.

The problems are written and prepared by user202729_, rama_pang, and pooty.

We would also like to thank:

  • Dr. Steven Halim for coordinating and teaching the CS3233 course;
  • user202729_ and rama_pang as teaching assistants;
  • (Pyqe, hocky, faustaadp) for testing the contest;
  • errorgorn for existing;
  • the Kattis team for the platform used in the CS3233 course and in the official contest;
  • Codeforces Headquarters for letting us announce on the main page; and finally
  • MikeMirzayanov for the amazing Codeforces and Polygon platform!

The contest will last for 5 hours and consist of 14 problems. While it is preferred to participate in a team, individual participation is also allowed.

The problems themselves may be quite standard as they are targeted toward those who have just learned competitive problem solving. However, we have also included a few challenging problems for stronger teams, such as ex-IOI or ICPC participants taking part in the course as well. So, the participants can expect a good mix of problems of varying difficulty levels, that we hope can be educational!

We hope you will enjoy and have fun in the contest. Good luck!

UPD: Contest is over! Editorial is up!

Congratulations to P+P+P (998batrr, 244mhq, 353cerega) for the win!

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By culver0412, 2 months ago, In English

Happy Easter, Codeforces! Sadly the round will not be Easter themed :(

We (arvindf232, culver0412, dbsic211, happy.potato, jerryliuhkg) are delighted to invite you to participate in Codeforces Round 865 (Div. 1) and Codeforces Round 865 (Div. 2), which will take place on Apr/09/2023 17:45 (Moscow time). Participants with a rating lower than 1900 will participate in Division 2, while participants with a rating of at least 1900 will participate in Division 1. Notice the unusual starting time.

All the problems were authored and prepared by arvindf232, culver0412, dbsic211 and happy.potato. Huge thanks to the following people, without whom the round would not be possible:

In both divisions, you will have 2 hours and 15 minutes to solve 6 problems. One of the problems is interactive, please see the guide of interactive problems if you are not familiar with it.

Wish you good luck and high ratings!

UPD1: Score distribution is as follows:

  • Div. 1: 500-1250-1750-2500-3000-3500
  • Div. 2: 500-1000-1250-2000-2500-3250

UPD2: Editorial

UPD3: Congratulations to the winners!

First solves

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By rui_er, history, 2 months ago, In English

Hello, Codeforces!

AC-Automation and I rui_er are glad to invite you to participate in Codeforces Round 864 (Div. 2), which will be held on Apr/08/2023 17:05 (Moscow time). Please note the unusual start time.

This round is rated for the participants with ratings strictly lower than 2100. You will be given 6 problems and 2 hours to solve them. All the problems are prepared by AC-Automation and me.

We would like to thank:

There will be a finite number of interactive problems, so please see the guide of interactive problems if you are not familiar with it.

The main character of the problems is Li Hua.

Who is Li Hua?

Statements and editorials will be available in Chinese (Simplified) after the contest.

This is our first round. We've tried our best to make the round enjoyable. We are looking forward to your participation and hope you gain a non-negative delta in this round.

UPD1: Score distribution: 500 — 1000 — 1500 — 1750 — 2250 — 3000.

UPD2: Editorial is out.

UPD3: Statement in Chinese and Editorial in Chinese are out.

UPD4: Congrats to the winners!


  1. syf2008
  2. zhukovaliza
  3. zhouzizhe
  4. psz1
  5. wnmrmr

Div.1 + Div.2:

  1. jiangly
  2. heno239
  3. SSRS_
  4. BurnedChicken
  5. Heltion

Also congrats to the only div.2 participant who solves problem F: reborn2023!

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By awoo, history, 2 months ago, translation, In English

Hello Codeforces!

On Apr/06/2023 17:35 (Moscow time) Educational Codeforces Round 146 (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 6 or 7 problems and 2 hours to solve them.

The problems were invented and prepared by Adilbek adedalic Dalabaev, 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:


Hey, Codeforces!

Once again, it is time for another exciting scholarship opportunity from Harbour.Space!

We are looking for talented individuals who want to launch their careers in Cyber Security with a 50% scholarship to study in Barcelona.

If you love technology and looking for an exciting career, then Cyber Security might be for you!

But don't just take our word for it — as a member of the Codeforces community, you know the value of continuous learning and growth. The Cyber Security master’s programme at Harbour.Space responds to a growing market need, driven by increasing threats of global cyberwarfare, for cyber professionals with advanced training in both defensive cybersecurity and offensive cyber actions. The programme is designed to provide the knowledge, skills, and abilities required to perform critical cybersecurity tasks successfully.


  • Bachelor’s Degree
  • Professional fluency in English
  • Your CV in English

What you will learn:

  • Applied Threat Intelligence
  • Threat Hunting
  • Reverse Engineering and Malware Analysis
  • Digital Forensics and Incident Response
  • Pentesting and Ethical Hacking
  • Hardware Conception of Processing Modules for the IoT
  • Networks and Protocols
  • Crisis Management and Communications
  • BlockChain and IAM
  • Soft Skills: Team Building, Presentation Skills and Meeting Facilitation
  • And more

Make sure to apply before April 30th, 2023, to be eligible for the scholarship and reduced application fee.


Keep in touch and follow us on LinkedIn for more scholarship opportunities. And follow us on Instagram to evidence student life, events, and success stories from students.

We are always happy to see Codeforces members join the Harbour.Space family.

Apply now to learn from the best in the field and take your career to the next level!

Good luck on your round, and see you next time!

Harbour.Space University

UPD: The contest is unrated. We apologize for the inconvenience.

UPD: Editorial is out

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By george_stelian, 2 months ago, In English

Dear Codeforces,

I am honored to share that the IX-th edition of the AGM International Programming Contest has officially begun!

AGM is addressed to High School students who compete in teams of up to 3 members, ICPC-style. The contest has 2 rounds:

  1. The Qualification Round held online, on Saturday, the 22nd of April between 15:00 and 20:00 GMT+3 (timeanddate)
  2. The Final Round held onsite, hosted by ICHB in Bucharest (Pallady Campus). The date and time will be announced soon.

Registrations are opened until Thursday, the 20th of April at 17:00 GMT+3:

The problem sets are entirely developed by current and former university students from the United Kingdom, Romania, and the Netherlands.

The top 10 teams of the Final Round will receive Diplomas. Additionally, the top 3 teams of the Final Round will receive cash prizes:

  • I-st place: 1200 RON
  • II-nd place: 900 RON
  • III-rd place: 600 RON

In the meantime, please have a look over the last three years' problem sets here.

Here are some useful links:

Finally, I am more than delighted to present our team: patrick.sava (the heart of the project), teoionescu, carabet.cosmin, Mihai22e, Stelutzu, munteanuvlad98, caesar2001, MiricaMatei, tinca_matei, georgerapeanu, kerO_o, popovicirobert, Alex18mai, ionan6ix, butasebi, Stefan_Radu, eman98, mihaicristian, and me

We are looking forward to welcoming everyone!

Kind regards,


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By Vladosiya, 2 months ago, translation, In English

Hello! Codeforces Round 863 (Div. 3) will start at Apr/04/2023 17:35 (Moscow time). You will be offered 6-8 problems 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 a rating of 1600 or higher, can register for the round unofficially.

The round will be hosted by rules of educational rounds (extended ICPC). Thus, solutions will be judged on preliminary tests during the round, and after the round, it will be a 12-hour phase of open hacks.

You will be given 6-8 problems and 2 hours and 15 minutes to solve them.

Note that the penalty for the wrong submission in this round 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 participant of the third division, you must:

  • take part in at least five 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 our work. Problems have been created and written by ITMO University team: MikeMirzayanov, myav, Aris, Gornak40, DmitriyOwlet and Vladosiya.

We would like to thank: Heltion, doreshnikov, powergee101, pashka, KseniaShk, 74TrAkToR, stefanbalaz2, playerr17, diskoteka, Nafis, nigus, erankyun, plourde27, Be_dos, donghoony, lucasxia01, Jostic11, sansen, gigabuffoon, akulenok, pwned, vrintle for testing the contest and valuable feedback. List of testers will be updated.

Good luck!

UPD: Editorial

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By Alexdat2000, 2 months ago, translation, In English

Hello, everyone at!

In this round, I (Alexdat2000) and two of my friends — FairyWinx and sevlll777 — prepared 6 problems for you (one of which is divided into two subtasks), and you will have 2 hours to solve them. Everyone is welcome to follow the link: Codeforces Round 862 (Div. 2) at Apr/02/2023 17:35 (Moscow time). This round will be rated for all participants with a rating of strictly less than 2100.

And now a few acknowledgements:

Scoring distribution: 500 — 750 — 1250 — 1750 — 2250 — (1750 + 1750).

UPD: Editorial

UPD-2: Congratulations to the winners of the round!

Top 5 official participants:

Place Participant Problems solved =
1 China b6e3 6 6987
2 Taiwan Darren0724 6 6683
3 cpbeginner 6 6520
4 China suckthembi 6 6269
5 GOD_0F_DEATH 6 5915

Top 5 of all participants:

Place Participant Problems solved =
1 China amiya 7 8214
2 China SSerxhs 7 7786
3 China Heltion 7 7750
4 Japan maspy 6 7623
5 Japan noimi 6 7255

Participants who sent the first correct solution to the problems:

Task Participant Penalty
A A_G 0:00
B USA Geothermal 0:02
C USA BucketPotato 0:08
D Hungary peti1234 0:11
E China b6e3 0:11
F1 BeyondHeaven 0:26
F2 China SSerxhs 1:37

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