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By ICPCNews, 8 days ago,

Hello, Codeforces!

This challenge edition is very special, as it will be happening in conjunction with the ICPC World Finals! For those who are not participating in the finals — ICPC and Codeforces are offering a unique chance to compete during a 4-day Challenge Marathon and win amazing prizes from Huawei!

ICPC Challenge Marathon (open to public, unrated): October 9-13, 2021, 00:00 UTC:

REGISTER

This time we’re delighted to provide you with a future-oriented topic – routing algorithms for next-generation communication. During this Challenge we will provide you with a super-large inter-satellite optical network to properly plan message paths, to reduce communication latency and improve resource utilization. However, finding the optimal path in a network with limited resources is an NP-hard problem. Considering the physical constraints of optics and circuits, our algorithm faces greater technical challenges:

• How can we model and abstract device constraints and design algorithms in the most appropriate way?
• Is there an algorithm that takes almost the same time to calculate routes as the network scale increases?
• Is there any way to obtain the theoretical optimal solution in a short period for ultra-large networks?

We hope that these satellite communications challenge questions can help you understand the problems that Huawei's software algorithm researchers face every day. All the best!!!

#### Prizes

For 3-hours onsite ICPC World Finals Challenge Huawei will provide prizes to the winners in 2 groups of participants:

• Group 1: TOP 30 ICPC World Finalists, who participate individually:

 1st-10th place HUAWEI MATE 40 Pro 11th-20th place HUAWEI MatePad Pro 21st-30th place HUAWEI WATCH 3 Pro

• Group 2: TOP 9 ICPC World Finals Coaches and Co-Coaches, who participate individually:

 1st-3rd place HUAWEI MATE 40 Pro 4th-6th place HUAWEI MatePad Pro 7st-9th place HUAWEI WATCH 3 Pro

For 4 days online Challenge Marathon, Huawei will provide prizes to TOP 30 individual participants:

 1st place* HUAWEI MateBook X Pro + 5000 USD 2st — 4th place HUAWEI MateBook X Pro 5th — 10th place HUAWEI MATE 40 Pro 11th — 16th place HUAWEI MatePad Pro 17th — 22nd place HUAWEI WATCH 3 Pro Classic 23rd — 30th place HUAWEI FreeBuds Studio

* The 1st place winner will get additional bonus in amount of 5000 USD. If the bonus cannot be transferred to the winner due to any reason, it may be replaced by a prize of the same value.

If the allocated Huawei Challenge prize cannot be delivered to your region for any reason it may be replaced by another prize of the same value (if no legal restrictions), at the discretion of the sponsor.

By participating in this Challenge, you agree to the Challenge Rules and Conditions of Participation

Good luck to all participants!

• +146

By awoo, history, 3 days ago, translation,

Hello Codeforces!

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!

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 tourist 6 82
2 LayCurse 6 158
3 LJC00118 6 159
4 mtsd 6 207
5 kefaa2 6 212

Congratulations to the best hackers:

Rank Competitor Hack Count
1 DreamingLeaf 20:-4
2 tzc_wk 12:-5
3 ooooxxxx 9
4 SSerxhs 9:-1
5 fireblaze777 10:-6
84 successful hacks and 270 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A Ormlis 0:01
B rasengans 0:01
C gleb.astashkin 0:05
D tourist 0:12
E tourist 0:21
F Potassium 0:23

UPD: Editorial is out

• +281

By MikeMirzayanov, 3 days ago,

Hello.

Sorry for it. Actually, right now I don't have any idea why testing is so slow now. Obviously, it doesn't work as expected. It is not because of problems. So please don't blame writers or coordinators. I'm investigating the reason, but don't see it now.

I myself am very upset and I apologize to the authors, coordinator, and participants. I will do my best to find the cause and fix it. Surprisingly, we haven't made any big changes to this part of the system lately. But something went wrong.

Mike.

• +1473

Hello Codeforces!

Asymmetry and I are glad to invite you to Codeforces Round #743 (Div. 1) and Codeforces Round #743 (Div. 2), which will be held on Sep/18/2021 17:35 (Moscow time).

Each division will have 6 problems and 2 hours to solve them. All problems were written and prepared by Asymmetry and me. The round will be rated for both divisions.

We would like to thank:

We've put great efforts into preparing this round and we hope that you will enjoy it.

Good luck!

UPD: We would also like to thank Ari for testing the round and KAN for translating the statements into Russian.

UPD2: Here are the scoring distributions:

Div. 1: $500$ — $1250$ — $1750$ — $2500$ — $2500$ — $3250$

Div. 2: $500$ — $1000$ — $1500$ — $2250$ — $2750$ — $3500$

UPD3: We are sorry that the round became unrated due to the long queue. We hope that you enjoyed the problems anyway.

## Winners

Congratulations to the winners!

Div1.

Div2.

UPD4: Editorial is out!

• +873

By shishin, 12 days ago,

Hello, Codeforces!

On Sep/12/2021 17:35 (Moscow time) we will host Codeforces Global Round 16.

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

The prizes 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 prizes 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 shishin and Artyom123.

We would like to thank these people:

You will have 2.5 hours to solve 8 problems. As always, we highly recommend reading all problems. Moreover, we really hope you upsolve the problems after the round, there are some interesting things to find out!

One of these problems is interactive, please see the guide of interactive problems if you are not familiar with it.

Score Distribution:

5007501000(750 + 1000)2000250030003750

Editorial:

The editorial

Winners

System testing finished, congrats to the winners!

Announcement of Codeforces Global Round 16

• +692

By awoo, history, 2 weeks ago, translation,

Hello Codeforces!

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!

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 Geothermal 6 183
2 qpEDop_MuXauJloBu4 6 216
3 hanbyeol_ 6 219
4 tute7627 6 221
5 fastmath 6 287

69 nice successful hacks and 304 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A Geothermal 0:00
B Geothermal 0:04
C Geothermal 0:07
D jayeshaw 0:18
E tzc_wk 0:28
F jiangly 0:30

UPD: Editorial is out

• +256

By MikeMirzayanov, 2 weeks ago,

Hello Codeforces!

I am in the process of making improvements and updates to the judgment machines. I've read the post https://codeforces.com/blog/entry/94587 and I think, maybe it is a good idea to make such a compilation line -O3 -funroll-loops -march=native -mtune=native? I haven't done any research that it is definitely better than -O2 and it is best in the general case for CP solutions. In a way, this will only strengthen the gap from Python/PyPy/Java, on the other hand: in pragmas and so you can set up everything. What do you think? What are suggestions to the command line?

P.S. You got it right. Yes, gcc11 std=c++20, pypy3 64-bit and more are coming.

• +822

By ScarletS, 3 weeks ago,

Hey there Codeforces!

flamestorm and I are glad to invite you to our first-ever Codeforces round, Codeforces Round #742 (Div. 2), which will be held on Sep/05/2021 17:35 (Moscow time). This round will be rated for participants with rating lower than 2100.

Special shoutouts to:

You will have 2 hours to work on (and solve!) 6 problems. At most one of the problems will be interactive. Make sure to read this blog and familiarize yourself with these types of problems before the round! You are highly encouraged to read all the problems ;).

UPD: The score distribution is 500 — 1000 — 1500 — 1750 — 2250 — 2750.

Good luck, and see you on the scoreboard!

UPD: Editorial is out!

UPD: Congrats to the winners!

Div. 2 (the only 5 contestants to solve the whole set!):

Div. 1 + 2:

We hope you enjoyed the round. See you soon!

• +967

By deltixlab, 4 weeks ago,

Hi Codeforces!

We are DELTIX. Founded in 2005, DELTIX is one of the market leaders in software development for financial research and products for systematic and algorithmic trading. In 2020 DELTIX joined the EPAM family. Our mission is to turn promising ideas into breakthrough products fast.

We are experts in:

• aggregation, storage, and processing large volumes of time-series data
• data modeling
• testing and deployment of quantitative models

In our team we value such skills as:

• knowledge of algorithms
• high-performance coding
• low latency data streams processing

We are excited to announce that one of our products TimeBase Community Edition joined a FinTech Open-Source Foundation (FINOS) on the 14th of July.

TimeBase is a multi-faceted, open-source data-streaming powerhouse, combining a time-series database, message broker, data modeling, and a well-optimized serialization framework. Originally, TimeBase was designed to address use cases in the financial domain. Nevertheless, we take on new challenges in other areas such as IoT, cloud computing, clustering, high-performance computing, parallel data processing, and Big Data to name a few.

Throughout the year, once per quarter, we will be inviting you to join DELTIX rounds at Codeforces. Today, we are excited to welcome you to the second installment of our rounds (joined Div. 1 and Div. 2) — Deltix Round, Summer 2021 (open for everyone, rated, Div. 1 + Div. 2), that will start on Aug/29/2021 17:35 (Moscow time).

It is an open and rated round for both divisions.

We have prepared the following trophies for you:

• 1st place = MacBook Air
• 2nd place = iPad Pro
• 3rd place = iPad Air
• 1-100 = branded t-shirts

Another 100 t-shirts will be distributed randomly between participants outside the top-100 but within the top-1000 and who participated in rated Codeforces rounds before.

All problems, except the last one, have been prepared by members of our team: Vladik, netman and AleXman111.

We would like to say a word of appreciation to:

We will offer participants 8 problems and 150 minutes to solve them. We wish everybody good luck and high ratings!

Fill out a short contact form if you are interested in employment opportunities or would like to speak with recruiters or members of our team.

Contact Form →

UPD: After processing all testers' feedback, we decided to extend the competition by 15 minutes. The total duration is 150 minutes.

UPD2: The scoring distribution is 500 — 1000 — 15001500 — 2000 — 2500 — 3000 — 3500. Note the equal complexity of C and D.

Thank you all for participating! (editorial)

Congratulations to the winners:
1. Miracle03
2. jiangly
3. Benq
4. Egor
5. TLE
6. ainta
8. Golovanov399
9. ecnerwala
10. maroonrk

• +595

By Wind_Eagle, 4 weeks ago,

Choose the way, five paths there for you to find
Turn the page, the question lies between the lines...

Hello, Codeforces!

I hoped that once there will be my second round, and finally, here it is!

I am very glad to invite you to the Codeforces Round #741 (Div. 2), which will take place in Aug/26/2021 17:35 (Moscow time). This round will be rated for the participants with rating lower than 100000110100 (2100).

My thanks to:

• antontrygubO_o for rejecting problems A his great coordination of this round! Thanks!

• gepardo made a lot. There wouldn't have been this contest if he didn't help me. Thanks!

• EIK this is the person who taught me competitive programming — my Informatics teacher. Thanks!

• MikeMirzayanov for Codeforces and Polygon platforms. Thanks!

• You for participating in this round. Thanks!

You will have 2 hours and 15 minutes for solving 6 tasks, one of which will be divided into easy and hard verions.

One of the problems will be interactive. So, it is recommended to read the ultimate guide on your favourite type of problems before the round.

I hope you will enjoy the round!

Round testers: kefaa2, BigBag, DreamingLeaf, Kuroni, programmer228, hu_tao, Vladik, bWayne, kassutta, asrinivasan007.

Score distribution: 500-1000-1250-(1250+1250)-2750-3500.

UPD: It was decided to add a sixth task to the round to balance the difficulty.

UPD2: Editorial is here!

UPD3: Congratulations to the winners!

Winners
Some other people who deserve congratulations