But why not!

Many people here seem to know me. Or maybe not quite? I am ready to answer your questions. Ask me anything! I plan to spend no more than 3 hours on answers. Sorry if I can't answer all the questions.

Let's more or less follow the rules from here https://www.reddit.com/r/IAmA/wiki/index

Below is actually a quote from the rules.

The interviewee begins the process by starting a post, describing who they are and what they do. Then commenters from across the internet leave questions and can vote on other questions according to which they would like to see answered.

The interviewee can go through and reply to the questions they find interesting and easily see those questions the internet is dying to have the answer to.

Because the internet is asking the questions, they're going to be a mix of serious and lighthearted, and you'll find yourself sharing all kinds of things you won't find in a normal interview.

Comments will be removed under a few circumstances:

• Abusive or harassing comments.
• Requests for personal favors from the OP (For example, "OP, can you send me a signed autograph").
• Top-level comments must ask a question.
• Comments where there would be no possibility of a real answer, especially where it is deliberately creepy or offensive.
• "I bet OP won't answer this"-type responses, which usually come after the OP has finished responding to questions.
• "Fluff," non-contributing responses from users, responding to all of the OP's comments for karma/attention.
• Repeatedly asking the same question.

Please, don't attempt to bypass the rules by adding a ? to a nonquestion.

Questions must be directed toward the individual(s) doing the IAMA.

Under our policies, astroturfing is the practice of an individual or group of individuals who plant questions in an IAmA post for a particular purpose. This kind of behavior is forbidden.

UPD 1: Oh, I'm kind of tired of doing this. Please keep asking questions. Tomorrow I will answer again. Don't forget to vote for the most interesting ones. I will not have time to answer everything, I will choose something. Thanks!

UPD 2:

Hi, Codeforces! Happy New Year!

I'm glad to invite you to Hello 2022, which will take place on Jan/03/2022 17:35 (Moscow time). You will have $$$2$$$ hours $$$15$$$ minutes to solve the problems. This round is rated for everyone.

All problems are authored by me. I would like to thank 74TrAkToR for excellent round coordination and MikeMirzayanov for great Codeforces and Polygon.

• Thanks to isaf27, budalnik, MichsSS, TadijaSebez, ijxjdjd, Um_nik, flamestorm, ashmelev, Monogon, errorgorn, Mr.Robot_28, AlexLuchianov, Kirill22, Prokhor08, romanasa, Dragonado, marzipan, magnus.hegdahl, olyazyryanova, DIvanCode, plagues, wxhtzdy, voventa, DanShaders, ptd, PurpleCrayon, stevancv for testing the round and giving valuable feedback.
• Thanks to Kapt, MForest for discussing some of the problems before the proposal with me.

There can be an interactive problem in this round. Don't forget to read the guide on interactive problems.

The scoring is $$$500-1000-1500-1750-2250-2750-3000-3500-4500$$$.

Good luck!

Editorial

Thank you for participation! Congratulations to the winners:

1. tourist

2. maroonrk

3. Radewoosh

4. Benq

5. djq_fpc

6. mnbvmar

7. ainta

8. 244mhq

9. ecnerwala

10. Rebelz

Hey!

Are you celebrating the New Year already? I wish you a Happy New Year. I wish you progress, joy and health.

We decided to show the current progress in the catalog of significant Codeforces posts.

So far, quite a bit has been implemented, but somehow you can already use it! Would you like to see it? Follow the link:

As planned, the catalog will collect and classify interesting and useful posts from Codeforces. Indeed, many useful articles have been written in Codeforces over 12 years (God, already 12 years!).

The catalog will be a kind of Codeforces golden fund in the future.

The catalog is a tree of topics to which posts can be added. We will still work on its functionality, for now there are only basic features. Don't be discouraged if something is not supported, which is very necessary — just let me know!

Any red user can enable directory editing. Remember that it is extremely important to make all changes thoughtfully and carefully. The tree should not become infinite in size. You need to have a sense of proportion when detailing topics. Please add only good, useful articles to the directory. If there is a disagreement on the contents of the catalog, the administration will make the final decision.

Hope this will be helpful. And together we can put together a catalog and keep the catalog up to date.

P.S. Many thanks to KAN who helped a lot with suggestions and catalog initial content.

Hello Codeforces!

We have a pleasure to invite you to Good Bye 2021, which will take place on Dec/29/2021 18:35 (Moscow time). You will have 2 hours to solve the problems. The round will be rated for participants of both divisions.

The problems for this round were prepared by 300iq, with the help of excellent coordinators KAN and 74TrAkToR.

We would like to thank all the testers, who made this round possible: gamegame, thenymphsofdelphi, ko_osaga, golions, Ashishgup, izban, prabowo, 74TrAkToR, Devil, manish.17, taran_1407, minhcool, AlFlen, Utkarsh.25dec, NemanjaSo2005, wxhtzdy, ajit, mnaeraxr, Scrubpai, YashDwivedi, eatmore!

And of course, MikeMirzayanov for great platforms Codeforces and Polygon.

This round is supported by NEAR, a company founded by former competitor AlexSkidanov. NEAR is built by many prominent competitive programmers, including twice ICPC champion eatmore and GCJ and TCO winner Egor.

The participants who end up in the first 255 positions will receive prizes. The participant on the first place will receive Ⓝ128, the next two participants will receive Ⓝ64, the next four participants will receive Ⓝ32, etc.

NEAR is a modern blockchain protocol and a development platform. NEAR applications have digital assets as a first class concept, and are hosted in a way that anyone can ascertain the correctness of their execution. This allows building applications that by design provide users with ownership over their assets, data and the power of governance.

If you want to try building on top of NEAR, join Metabuild, a hackathon running until February with $1M in prizes: https://metabuild.devpost.com/

We hope you will enjoy the problem set! Good luck!

Congratulations the winners!

1. tourist
2. ecnerwala
3. ksun48
4. Radewoosh
5. Benq

UPD: Editorial

Hello.

Here's a small improvement for posts and comments. Likes can now be specified in their markup. Maybe this will be useful for organizing some kind of polls or collecting feedback.

Here are some examples:

Yes, I know that this feature can be improved. I would prefer that we try to use it a little and understand what exactly is missing the most. Maybe we need to implement the fully functional polls.

Let's do a small survey using the new feature.

1. What is your age range?

   • under 16:
   • 16-20:
   • 21-25:
   • 26-35:
   • 36+:

2. Tabs or spaces?

   • tabs:
   • spaces:

3. Have you had covid??

   • yes:
   • no:
   • I don't know:

4. Lately, there have been a lot of meaningless blogs on Codeforces. Is it worth strengthening measures to fight against them?

   • yes definitely:
   • rather yes, but not necessarily:
   • rather no, I read some of them:
   • no definitely:

Hello Codeforces!

Kotlin Heroes: Episode 8 was the third round of the Kotlin Heroes series in 2021. The “8” from “Kotlin Heroes: Episode 8” symbolizes our infinite respect for all who participated! We are very happy to see new people learn Kotlin and perform brilliantly in the competition. All the previous rounds are available to be used for practice here: Episode 1, Episode 2, Episode 3, Episode 4, Episode 5: ICPC Round, Episode 6, and Episode 7.

Сongratulations to the top three contestants:

• SpyCheese
• Sugar_fan
• eatmore

A Kotlin Heroes t-shirt and exclusive Kotlin stickers will be presented to:

These participants also won branded t-shirts:

We will contact the winners soon to coordinate the delivery of your prizes!

The Kotlin Heroes: Episode 8 practice round took place during the ICPC World Finals. Gennady “tourist” Korotkevich, a repeat winner of Kotlin Heroes, was solving the practice round tasks during the event opening. We invite you to watch this presentation.

For those who would like to get to know Kotlin better, we invite you to check out Kotlin Basics track on JetBrains Academy, take a look at basic Kotlin, solve Koans in the free course from JetBrains Educational Products, visit Kotlin Playground, check out the tutorial, and these videos on competitive programming in Kotlin.

More information about Kotlin Heroes contests: https://kotlinlang.org/lp/kotlin-heroes/.

We wish you luck and hope you enjoy Kotlin!

Hello, Codeforces!

I am really excited to invite you to Codeforces Round 763 (Div. 2) on Dec/28/2021 16:35 (Moscow time)! The start time is unusual, so please pay attention.

All the problems were authored and prepared by me. I would like to give special thanks to everyone who made this round possible:

• KAN for excellent coordination with a lot of valuable advice!
• KAN again for translation of statements!
• tdpencil, Stepavly, Supermagzzz, minhcool, snowysecret, generic_placeholder_name, QuangBuiCPP, thenymphsofdelphi, PurpleCrayon, xuanquang1999, vinfat, hieplpvip, tourist, Lihwy, flamestorm for testing and valuable feedback!
• MikeMirzayanov for great Codeforces and Polygon platforms!
• You, for participating!

The round consists of 5 problems and you have 2 hours to solve them.

Wish you good luck and high ratings!

UPD0: The score distribution 500 — 1000 — 1750 — 2500 — 2750.

UPD1: Congratulation to the winners of the round!

Div. 2

1. wanyuezaifengli
2. ZhuJianfeng
3. proton1126
4. qazsxdew
5. Hayasaka

Div. 1 + 2

1. heno239
2. Geothermal
3. Vercingetorix
4. dorijanlendvaj
5. wanyuezaifengli

UPD2: The Editorial is out!

Hope that you guys enjoy the rounds, and thank you again for participating! <3

Hello Codeforces!

On Dec/27/2021 17:35 (Moscow time) Educational Codeforces Round 120 (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, Vladimir vovuh Petrov, Ivan BledDest Androsov, Maksim Neon Mescheryakov, Roman Roms Glazov and me. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

UPD: Editorial is out

Hello Codeforces!

Oh yes, 2021 ends! I recently realized that 2022 is pronounced like "2020 too". Not that. I want a completely different year!

Anyway, we did a nice job this year. I hope we have pleased you with interesting problems. Thanks to the round coordinators and writers! You make our community richer. Please make us happy in 2022!

I wish you all interesting tasks and brilliant solutions! I wish you error-free code and wish us only rated rounds :-)

Hello, 2022!

And we have traditional gifts!

Change Handle Feature

Hurry! Only until the 10th of January, you can change your handle (but only once)! Note that it will be possible to roll back the changes or change the handle again only after a year. Be careful what you wish for.

You can change your handle to the new one which wasn't used before by anybody or which was used by you before. The links to a profile page with an old handle would automatically redirect to the actual profile.

Again, this year if you took part in at least 10 rounds you can request a handle of an inactive participant. It means that the participant should have a period of activity on Codeforces of at most 180 days, this period should be in 2019 or earlier. The inactive participant can't have posted comments, messages, and so on. It can't take part in more than 2 contests. It will be automatically renamed and informed by email. A user has the opportunity to request back his/her handle: in this case, we will roll back the change and return your previous handle to you. If you can't change your handle to another, it means that some requirements don't meet. Please do not ask me to do something with it. Especially, I do not like requests like "this is my second account, I took an interesting handle myself". I'm not Santa Claus.

Talking about handles I always
reminisce the following story. Once a user wrote me the message: "Please change my handle from I_love_Valya to I_love_Sveta, as I no longer love Valya ..."

New Year's Masquerade of Colors and Ranks

The traditional magical tab has appeared in the profile setting. Happy New Year!

Happy Holidays!

On Dec/24/2021 17:35 (Moscow time) we will host Codeforces Global Round 18.

It is the sixth round of a 2021 series of Codeforces Global Rounds. The rounds are open and rated for everybody.

The presents for this round:

• 30 best participants get a t-shirt.
• 20 t-shirts are randomly distributed among those with ranks between 31 and 500, inclusive.

The presents for the 6-round series in 2021:

• In each round top-100 participants get points according to the table.
• The final result for each participant is equal to the sum of points he gets in the four rounds he placed the highest.
• The best 20 participants over all series get sweatshirts and place certificates.

Thanks to XTX, which in 2021 supported the global rounds initiative!

The problems were written and prepared by the hard-working elves Monogon, BledDest, and PurpleCrayon.

We would like to thank the everyone who made this round possible:

• The fabulous reindeer awoo, QuangBuiCPP, manish.17, Lyde, penguinhacker, Maksim1744, BucketPotato, magnus.hegdahl, ecnerwala, ItayOtto, ijxjdjd, actinium16, gamegame, kpw29, Um_nik, TadijaSebez, and AliShahali1382 for testing the round and providing valuable feedback to the problems!
• antontrygubO_o, the most famous reindeer of all!
• adedalic, for excellent coordination of the round!
• Saint Micholas Mirzayaclaus, MikeMirzayanov, for the amazing Codeforces and Polygon platforms!
• All the nice boys and girls who participate!

You will have 2.5 hours to solve 8 problems.

UPD: The scoring distribution: 250 — 1000 — 1750 — 2250 — 2750 — 3000 — 3750 — 4000

UPD: Editorial is out!

Good luck, have fun, and stay off the naughty list!