Hello, Codeforces!

I am happy to invite you to Codeforces Round 771 (Div. 2), which will take place on Feb/14/2022 17:35 (Moscow time). The round will be rated for participants with rating lower than 2100. You will have 2 hours to solve 6 problems. The problems were authored and prepared by me.

I would like to thank the following people who made the round possible:

• Artyom123 for coordination, help in problem preparation and translating the statements.
• KAN for helping with round preparation.
• geniucos and spatarel for discussing problems with me way before the round was proposed.
• gamegame, I_love_teraqqq, AlexLuchianov, Monogon, wxhtzdy, generic_placeholder_name, BlueDiamond, Devil, Ziware, Utkarsh.25dec, TeaTime, null_awe, manish.17, gojira, shishyando, snowysecret, ak2006, namanbansal013, viovlo and sus, for testing and providing valuable feedback.
• MikeMirzayanov for great Codeforces and Polygon platforms.

I hope you have no plans for Valentine's Day find the problems interesting and enjoy the round. See you in the standings! ❤

Scoring distribution: $$$500-750-1250-1750-2500-3250$$$

UPD: Thanks to ak2006, video editorials for some of the problems will be available on his channel after the round.

UPD: Editorial is out!

Hello, Codeforces! (づ｡◕‿‿◕｡)づ ❤

On Feb/12/2022 17:35 (Moscow time) we will host Codeforces Global Round 19.

It is the first round of a 2022 series of Codeforces Global Rounds supported by XTX Markets. 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 2022:

• 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.

The problems were written and prepared by Mangooste, TeaTime, __JustMe__ and EvgeniyPonasenkov.

We are very thankful to people, who made this round possible:

• DmitryGrigorev for the great coordinating and helping us with preparing problems.
• Our testers: gamegame, dorijanlendvaj, fedoseev.timofey, tfg, fastmath, allvik66, Pechalka, Alexdat2000, pakhomovee, Frankenween, philmol, Ultrasanic, tox1c_kid, Viktoriuss and Urvuk3 for their feedback, especially tfg for finding mistakes in the statements.
• MikeMirzayanov for codeforces and polygon platform!
• KAN for his contribution to this round as well.

You will have 2.5 hours to solve 8 problems. And we recommend you to read all the problems!

The score distribution will be announced closer to the start of the round.

UPD: The scoring distribution: 500 — 1000 — 1500 — 2000 — 2500 — 3250 — 4000 — 4000

UPD: Editorial.

Congratulations to the winners:

1. tourist
2. Um_nik
3. Maksim1744
4. heno239
5. ksun48
6. Vercingetorix
7. jiangly
8. SomethingNew
9. Laurie
10. VivaciousAubergine

Greetings to all humans and robots on this site!

sevlll777, crazyilian, Mangooste, purplesyringa and me (Alexdat2000) invite everyone to participate in the Codeforces Round #770 (Div. 2), which will take place this Feb/06/2022 17:35 (Moscow time). This round will be rated for all participants with a rating of strictly less than 2100. You will have 2 hours and 30 minutes to solve 6 problems. There will be an interactive problem in the round, so we recommend all new participants to read Interactive Problems Guide.

The traditional thank-you list:

• Thanks to antontrygubO_o for coordinating us for a very long time and helping to improve one of the tasks
• Thanks to alexxela12345 for tasks that did not survive till the final version of the round
• Thanks to Pechalka, alexxela12345, I_love_teraqqq, physics0523, PurpleCrayon, I_love_kirill22, tem_shett, FairyWinx, Dart-Xeyter, Vladithur, Igorfardoc, despair_101, shishyando, Brahma_tet and kLOLik for quality testing of the round and very helpful feedback
• Thanks to MikeMirzayanov for the Codeforces and Polygon

Scoring distribution: 500 — 1250 — 1500 — 2000 — 2500 — 3000.

Codeforces Round #770 (Div. 2) is ready to resist the rise of machines

We wish all participants high rating! Show that people are still worthy!

UPD: Editorial

Hello, codeforces!

Pinely is a high-frequency trading company. We trade at the exchanges all over the world. This year we are the sponsors of the online PTZ competitive programming camp. We have prepared a fun contest for camp participants and invite everybody to join it on CodeForces!

Pinely Treasure Hunt Contest will be held on Saturday, Feb/05/2022 13:00 (Moscow time).

The participants will be offered to solve an interactive optimization problem with open tests and will have 3.5 hours to work on it. You can join individually or in teams of up to 3 people. The contest will be unrated. Winners among camp participants as well as the 3 best teams in overall standings will be awarded with pinely t-shirts.

Since the contest is targeted for participants of the PTZ training camp, it'll be most interesting for participants with codeforces rating 2000+.

We are grateful to MikeMirzayanov for the opportunity to host the contest on codeforces.

A couple of words about pinely: we conduct algorithmic trading on various exchanges. Our offices are located in Amsterdam, Singapore and Cyprus. Our colleagues face various challenges, such as: coming up with trading strategies and implementing them, optimizing trading systems to achieve the fastest reaction to the market events, storage and processing of high volumes of historical data. Ability to write effective C++ code, algorithmic thinking and mathematical intuition are all useful in our day-to-day work, so a significant part of our team participates in various programming and math competitions.

To learn more about pinely you can visit pinely.com or you can find our colleagues on CF in pinely organization. You can send us your CV to [email protected], even if you are not participating in the contest.

Good luck and have fun!

UPD Congratulations to the winners!

Winners of the joint contest:

1. itmo.algo.teaching: tourist, pashka, budalnik

2. SPb NRU ITMO 3: VArtem, antonkov, qwerty787788

3. xyr and his friends: wygzgyw, frame233, wasa855

Winners among the participant of PTZ training camp:

1. Never Give Up: Valera_Grinenko, ivanz, 353cerega

2. Saratov SU Daegons: awoo, Neon, vovuh

3. A-SOUL_Unofficial: Pub, pigstd, dXqwq

Hello, community.

Today DeepMind announced a new achievement of AI. And it is directly related to what we love — programming problems.

They have developed AI capable of solving some competitive programming problems! The future has arrived.

You should read solutions of SelectorUnlimited, WaggleCollide, and AngularNumeric solutions. All solutions are written automatically. The only input for writing solutions is a problem statement in English.

Details can be read at the link https://deepmind.com/blog/article/Competitive-programming-with-AlphaCode

Apparently, if these accounts would take part in real competitions, then their rating would be about 1300.

Terminator is ready to take part in Codeforces Round #770 (Div. 2)

In 1997 Kasparov played against (and lost) the supercomputer DeepBlue. Perhaps we will be witnessing a confrontation between tourist and AI in near future. What do you think?

Hello Codeforces!

On Jan/31/2022 17:35 (Moscow time) Educational Codeforces Round 122 (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 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.

Hi, Codeforces!

Vladithur and I are pleased to invite you to our Codeforces Round 769 (Div. 2), which will be held on Jan/30/2022 17:35 (Moscow time). This round will be rated for participants with rating lower than 2100.

We would like to express our great gratitude to:

• irkstepanov and KAN for not rejecting our tasks excellent coordination of the round and assistance in preparing problems.
• Ormlis, antontrygubO_o, generic_placeholder_name, Alexdat2000, Dart-Xeyter, wxhtzdy, sohsoh, glebustim, radal, snowysecret, stevancv, maxverr, Scrubpai, Artem1303, RomkaRS and MaxShch for testing the round and providing useful feedback.
• MikeMirzayanov for cool platforms Codeforces and Polygon.

You will have 2 hours to solve 5 problems, one of which is divided into two subtasks.

The scoring distribution is 500 — 1000 — 1500 — 2000 — (1500 — 1500)

We have tried to make clear statements and strong pretests for the problems and hope you will have fun and increase your rating!

Good luck!

Also, we would like to start the trend of evaluating the round's problems. We think it will give valuable feedback to authors and make future contests better. So please, vote for each problem after the round's end.

UPD: Editorial is here.

UPD2: Congratulations to the winners!

Div. 1 + Div. 2:

1. kotatsugame
2. tute7627 and jiangly
3. -
4. I_Iove_chtholly
5. Alan_girlfriend

Div. 2:

1. I_Iove_chtholly
2. Alan_girlfriend
3. Wlxsohandsome
4. 778
5. i_will_be_less_than_blue

Hello codeforces!

BrayanD, dmga44 and I are glad to invite you to Codeforces Round 768 (Div. 1) and Codeforces Round 768 (Div. 2) which will be held on 27.01.2022 17:35 (Московское время).

Each division will have 6 problems, and you will have 2 hours to solve them. The round will be rated for both divisions.

We would like to thank:

• Aleks5d for his excellent round coordination.

• albertolg101 and jmrh_1 for helping in the early stages of the contest.

• ashmelev, nweeks, 16204, amanbol, Ali.Kh, vaaven, marcOS, low_, Riladavin, TeaTime, MDario, aniervs, Dragonado, Saborit, 4qqqq and saarang for testing and providing useful feedback.

• MikeMirzayanov for the great platforms Codeforces and Polygon.

Score Distribution:

Div. 2: $$$500 - 1000 - 1500 - 2250 - 2250 - 3000$$$.

Div. 1: $$$500 - 1250 - 1250 - 2000 - 2500 - 3000$$$.

Good luck to all participants! Hope you enjoy the contest.

UPD1: Editorial

UPD2: Congratulations to the winners.

Div. 1:

1. Um_nik

2. kiwihadron

3. heno239

4. ksun48

5. Radewoosh

6. maroonrk

7. 244mhq

8. Vercingetorix

Congratulations to all of them for solving all problems!

Div. 2:

1. YuulBA

2. wcdr

3. Dalia12

4. hrgd

5. Pure__Vessel