kostka's blog

By kostka, 2 days ago, In English
 
 
 
 
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By kostka, 12 days ago, In English

Remember when I asked if you would be interested in buying a book about the sports programming?

It's been a long journey and there's even a preprint version of this book sitting on my desk. But then I realized that I would hate myself if I tried to profit from this book. It contains a lot of knowledge that was shared with me by some of the members of this community. Therefore I decided to share the PDF for free, for everyone.

This book is a collection of algorithms and data structures used in sports programming that I found interesting with example problems from various past competitions. I also tried to describe various competitions and platforms. Hope some of you will find it helpful!

Obviously, the book may contain some errors (in particular please note that English is my third language). If you want to help, please let me know about them! I would love to fix them and then share a corrected version in the future. I might even send you a thank-you postcard or a physical copy of this book. The feedback form is available on my website, alongside the book.

Enjoy!

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By kostka, 12 days ago, In English

I believe it went a little bit unnoticed here, so let me congratulate the Top Coder Open 2022 winners:

  • First place and $10000: tourist (for the fifth time!)
  • Second place and $3500: maroonrk
  • Third place and $500: ecnerwala

And congrats to Psyho on his 7th win in the Marathon track!

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By kostka, 3 weeks ago, In English

In Sharm El Sheikh. It was announced on the stream.

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By kostka, 2 months ago, In English

From ICPC regional rules:

The ICPC World Finals cycle is still affected by the pandemic, and the ICPC World Finals Dhaka in November 2022 is for the teams qualified from the regional year 2020/21. To come back on track the ICPC is planning to determine the two World Championships for the regional years 2021/22 and 2022/23 simultaneously at the same event with separate acknowledgement of champions and medalists. The target date for this event is the last week of November 2023.

And further:

A student may compete in only one of these two Championships.

A qualified student on different teams that qualify for ICPC World Finals 2022 and ICPC World Finals 2023 will participate on the team qualifying for the 2023 World Finals. The coach of the team qualifying for the 2022 World Finals may request a qualified replacement. Details later.

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By kostka, 2 months ago, In English

In short: "TCO22 Finals has been moved to an all virtual event. Due to the lack of finalists able to join in person, we had to make the call to not have a full scale, in person TCO. "

Full article: https://discussions.topcoder.com/discussion/22462/2022-topcoder-open-finals-announcement-change-of-plans

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By kostka, 2 months ago, In English

Round F starts in less than an hour! See you on the scoreboard!

http://goo.gle/KS-2022-F

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By kostka, 3 months ago, In English

All the delegations participating in EJOI 2022 have been published: https://olympiads.jsoft.am/Olympiads/Details/45#

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By kostka, 4 months ago, In English

As the results of the IOI 2022 are now official, I would like to wholeheartedly congratulate:

  • Benjamin Bajd on the first gold medal for  Slovenia (after 4 tries!)
  • Egor Georgievskii on the first ever medal for  Montenegro (he was the only participant in his country's delegation this year)
  • Nicola Abusaad on the first ever medal for  Palestine
  • Rolly Mamani on the first ever medal for  Peru (this was also the first time when Peru participated in the IOI!)

Congratulations to all! I really hope you all just opened the bag of medals for your countries!

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By kostka, 4 months ago, In English

... will take place in Bolivia! This will be the second time that IOI will be hosted in South America, after IOI 1993 in Argentina!

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By kostka, 6 months ago, In English
 
 
 
 
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By kostka, 7 months ago, In English

Join us for another round of our online coding competition and tackle fun problems designed by Google engineers!

➡️ g.co/kickstart.

Round B starts in less than 24 hours (on April 23rd, 2022, at 23:00 UTC)!

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By kostka, 7 months ago, In English

As in the previous years, I want to create a list of people participating in the next IOI. Please add participants from your country using this form: https://forms.gle/5J8P4dG8vnUwjBjh7. Feel free to also comment here with their handles for visibility.

The list is available at https://kostka.dev/ioi/22/ .

Lists from the previous years: https://kostka.dev/ioi/21/, https://kostka.dev/ioi/20/ (I know the flags are broken, but I don't want to update them, as the ratings will change as well).

If you see any mistakes, either fill the form again with the correct data or message me.

Thanks!

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By kostka, 8 months ago, In English

The Code Jam Qualification Round has officially begun! → goo.gle/cj2022

You've got until 02:00 UTC on April 3 to register AND score enough points (at least 30) to advance to Round 1.

Registration closes at the end of the round!

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By kostka, 8 months ago, In English

It's a good movie. Go watch it.

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By kostka, 9 months ago, In English

Kick Start is back for our tenth year! Join this online global coding competition offering beginner to advanced coders the space to develop programming skills and become better acquainted with competitive programming. We offer challenges at different times throughout the year so you can join in on the fun whenever it’s convenient for you – check out the round schedule.

Our first official round of the year (round A) starts on March 20th 2022, 04:00 UTC.

Before the round, be sure to:

  • Take a look at our helpful tutorial video, to learn more about the competition platform and some useful tips and tricks.
  • Practice out past problems and review the FAQ.
  • Check out our YouTube playlist, where you’ll find problem walkthrough videos hosted by Google engineers.

Sign up today!

Hope you'll join us for Round A!

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By kostka, 9 months ago, In English

IOI has issued a statement: https://ioinformatics.org/news/ioi-response-to-invasion-of-ukraine/40

In short:

  • the IC strongly condemns the invasion of Ukraine by the Russian Federation
  • the Russian delegation will not be invited to IOI 2022 (but they can participate online under the IOI flag)
  • there is still an ongoing discussion regarding the Belarusian delegation

I am curious about what the community thinks of this decision and its repercussions.

Update, 26 April 2022: The delegation from Belarus will be subject to the same restrictions as described above for Russia.

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By kostka, 9 months ago, translation, In English

This post will probably become very political, but I am very worried about things happening right now in Ukraine. I know this is not the best place for such discussions, but fuck it, a lot of people visit this website and some things have to be discussed.

Can you please tell me, dear Russians, do people there (you, your friends, and your families) really believe in all the things that Putin says about Ukraine? Are you proud of living in a country that invades a neutral neighbour?

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By kostka, 10 months ago, In English

Coding Practice with Kick Start Session 1 is underway!

Join this four-day session to:

  • Get familiar with the Kick Start platform
  • Work on algorithmic coding problem problems
  • Improve your coding skills with help from Googlers

Register now → http://goo.gle/KickStart2022

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By kostka, 10 months ago, In English

How junior olympiads (grade 8 or less) look like in your countries? Can you share some info/your experiences/links?

In Poland, we have an annual contest with three stages (first online, second and third onsite). During the first stage, we also have a test checking language proficiency (C++ or Python) and the ability to solve algorithmic puzzles. During the final stage, top X contestants are selected to attend the preparation camp and the EJOI.

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By kostka, 14 months ago, In English

Whether you’re looking to practice your coding, prepare for an upcoming interview, connect with a global community, or have some fun — Kick Start is here to help! Round G 2021 starts in less than 24 hours on October 16 starting at 12:00 UTC. You will have 3 hours to solve what you can during the round.

Hope to see you in Round G 2021!

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By kostka, 14 months ago, In English

... for "solving the problem of making sure there's an opportunity for everyone to participate" (the program is called ACPC for girls). What about all the issues related to this regional that are still unanswered (link 1, link 2)?

Good job, ICPC, again! Now give each team the 4th computer!

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By kostka, 14 months ago, In English

Whether you’re looking to practice your coding, prepare for an upcoming interview, connect with a global community, or have some fun — Kick Start is here to help! Round F 2021 starts in less than 24 hours on September 18 starting at 17:00 UTC. You will have 3 hours to solve what you can during the round.

We are excited to announce we are now supporting PyPy3 and updated compilers and interpreters for several languages. You can find more information in the Platform section of the FAQ.

Hope to see you in Round F 2021!

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By kostka, 15 months ago, In English

Join our online coding competition and tackle fun problems designed by Google engineers! ➡️g.co/kickstart

Round E starts in less than 12 hours (on August 22nd at 03:30 UTC).

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By kostka, 16 months ago, In English

In the last contest, both tourist and ko_osaga copied the author's solution from the problem Matrix from Petrozavodsk Winter Camp 2013 Warsaw U contest: 123723552 and 123727448 respectively. You can easily verify that they didn't write this code themselves by looking at the comments in these solutions (written in Polish).

This is against the Codeforces rules. According to this post, we have the following rules:

Solutions and test generators can only use source code completely written by you, with the following two exceptions:

  1. the code was written and published/distributed before the start of the round,
  2. the code is generated using tools that were written and published/distributed before the start of the round.

and

Currently, the only reliable proof is the presence of code on the Internet and the presence of the used edition in the cache of well-known search engines.

For example, this rule accepts the use of the code from the website http://e-maxx.ru/ if the code was written and published/distributed before the start of the round. With the help of search engine caches, it can be easily shown that such code doesn't violate the rules. Similarly, it is permissible to use the code from a book/article that was published before the contest. On the other hand, using team reference code (for example, prepared for ACM-ICPC World Finals) is not allowed if there is no reliable and objective way to prove that the code was written before the contest.

This code is not available on the Internet publicly and was never published anywhere (at least I am not aware of that). There are two ways to get access to this code: either ask the author or have admin access to one of the contests where this problem is used. In my opinion, this falls into the second category (same as team reference code), as only a small number of people have access to this. Moreover, imagine if a similar issue would occur to some unknown, green or grey contestants. Their solutions for sure would be skipped. Please stop this elitism and ratism and treat all the contestants equally.

I am not saying that we should ban them or skip their solutions, but we should make sure that the rules are clear and fair and there are no exceptions. Maybe if you are using a third-party code, you need to add a comment mentioning the original source of the problem and this solution doesn't have to be widely available, but can be verified upon the request of someone investigating this potential cheating case? If that's the rule that we currently use, please add this to the aforementioned blog.

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