I'm excided to finally show my interview with ko_osaga that was recorded way too long ago (at World Finals, sorry ko_osaga). Still, I believe the conversation is timeless, so check it out! I was a big fan of ko_osaga back in high school, as he was one of the few top guys that was still active in the Olympiad community. He's the original creator of the OI checklist, IOI gold medalist and finalist of most big competitions you can think of. Now, he's a PhD candidate at MIT — we talk about the journey from competitive programming to algorithms research, competitive programming in South Korea and much more.

P.S. As I mentioned in my last blog post, I've changed jobs and have much less time for working on Olympicode. I've also finished my ICPC career at last World Finals, so I don't expect to travel to many competitions in the near future, so this might be the last interview for a while. Might try switching to some online interviews, but I feel like that takes away a lot of the magic of in-person interviews.

Additionally, since only a few people are submitting to Olympicode Judge a month and I've been paying for the hosting and everything, I decided to shut it down for now, until I decide what to do with it. We'll port the Olympicode Open Olympiad to the Codeforces Gym at some point (or another judge is welcome to publish it, all the data is in the OOO blog post). Everything else you can now submit elsewhere.

Thank you all for the support, it was great meeting some of you in-person and stay tuned for what the future holds (once I figure it out :) ).

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg
• m

  aroonrk
  : https://youtu.be/HFK9gqur93Y
• pashka
  : https://youtu.be/IyuQBbBJhe4
• e

  rrorgorn
  : https://youtu.be/fMEeE-Icjv4
• Psyho
  : https://youtu.be/fB0piX9YbEg
• TheScrasse
  : https://youtu.be/4v0kaUtecoY
• E

  rrichto
  : https://youtu.be/IsEPi_c0Y2A

After a few crazy months of travel, changing jobs, trying to finish university and so on, it's finally time to release the next interview :)

Back when I was in Warsaw I sat down with Errichto, who probably doesn't need much of an introduction, but still — he deserves it. He's a huge pillar of the community, with his educational content, YouTube channel, classes, problemsetting and so much more. He's one of the best ambassadors for the sport and it was fun to talk to him about what his beginning were, as well as what his life looks like now. You won't want to miss this one :)

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg
• m

  aroonrk
  : https://youtu.be/HFK9gqur93Y
• pashka
  : https://youtu.be/IyuQBbBJhe4
• e

  rrorgorn
  : https://youtu.be/fMEeE-Icjv4
• Psyho
  : https://youtu.be/fB0piX9YbEg
• TheScrasse
  : https://youtu.be/4v0kaUtecoY

A few months ago (yes, I'm very slow at editing these), I got the chance to talk to TheScrasse at the Midnight Code Cup. We talk about how he started coordinating on Codeforces, how he creates new problems and his overall competitive programming journey.

We also talk about one of my favorite topics — coding duels. He was one of the pioneers in this area, having done a few great livestreamed duels in the past few years. Watch to see his opinions on coding duels.

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg
• m

  aroonrk
  : https://youtu.be/HFK9gqur93Y
• pashka
  : https://youtu.be/IyuQBbBJhe4
• e

  rrorgorn
  : https://youtu.be/fMEeE-Icjv4
• Psyho
  : https://youtu.be/IyuQBbBJhe4

PS. A few of you came up to me on World Finals to let me know you watch the interviews — thanks a lot! Creating these takes a lot of effort (also, equipment is really hard to carry on trips :) ), so it means a lot to meet the people that enjoy these.

A few weeks ago, a huge story shook the competitive programming world. Headlines everywhere asked the same question: is this the last human champion? Even local Serbian newspapers joined the debate, wondering if the recent AtCoder World Tour Heuristic Finals would be the final time a person could defeat an AI.

I went to Warsaw to meet the man who pulled it off — Psyho. We talked about the contest itself, what he knew about the AI bot going in, and how he managed to come out on top.

If you don’t already know, Psyho is the greatest heuristic competitive programmer of all time, with over 20 years of experience. He was also one of the first employees at OpenAI, where he worked on the Dota bot — one of their earliest landmark projects.

We cover all of that, and more, in the longest episode yet!

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg
• m

  aroonrk
  : https://youtu.be/HFK9gqur93Y
• pashka
  : https://youtu.be/IyuQBbBJhe4
• e

  rrorgorn
  : https://youtu.be/fMEeE-Icjv4

After a few months break from interviews, we're back with some interesting discussions. I have recorded 4 interviews since the last published one and will be releasing them in the near future. First one is a great discussion with errorgorn. He's a two time IOI gold medalist, an LGM and of course a great contributor to the community through his round coordination and blogs (which shows on the contribution ranklist!). Listen in to hear about his coordinating philosophy and his journey through competitive programming.

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg
• m

  aroonrk
  : https://youtu.be/HFK9gqur93Y
• pashka
  : https://youtu.be/IyuQBbBJhe4

Hey everyone,

I will be in Warsaw for a few days recording some interviews. I will be also meeting Radewoosh again and since I already had the chance to ask him questions, we thought it would be cool to give you the opportunity as well!

We will be recording in a few days (probably Thursday), so post your questions below and we will record the answers to as many as we can :)

Hey everyone,

Last month I participated at the Midnight Code Cup in my hometown with milisav and Pajaraja. We enjoyed it so much, I made a video with Paja discussing our favorite (and not so favorite) moments. If you're interested in the discussion of the event, problems and general vibe of the onsite, you can check out our video here. Overall, it was incredibly fun, so once again, thanks to the organizers :)

I also recorded two interviews during the competition — as usual, let's give some hints and you can guess the guest in the comments!

• He participated at the Midnight Code Cup finals (obviously)
• He is a Legendary Grandmaster
• Apart from Competitive Programming and math, you can often find him discussing learning languages on his blog

First person to guess it gets to see the video before everyone else :)

No, this is not clickbait (maybe). Researchers Ran Duan, Jiayi Mao, Xiao Mao, Xinkai Shu and Longhui Yin recently published a paper showing their deterministic $$$O(m\log^{2/3} n)$$$ algorithm for the directed Single-Source Shortest Path problem on sparse directed graphs — breaking almost 70 years of Dijkstra's reign in this field. I have yet to read it (looking forward to it, hopefully I can understand it) — but this shows that the common misconception that all interesting algorithms have been discovered is very wrong.

Also, if the name Xiao Mao sounds familiar — it did to me as well. It's the real name of matthew99, former LGM and ICPC World Champion — not sure if that's him, but it would be cool. Also found a GM Jiayi Mao on CF — AbstractKangaroo. Again — I have no idea how common these names are, but it wouldn't surprise me if it's them :)

We're trying something new at the Olympicode channel, I tested some of my friends' CP lore knowledge (and might have expected too much on this first one). It was really fun for us to record, hopefully it will be fun for you as well (and hopefully it will be even better in the further episodes as I get the hang of it more)

If you're missing the interviews, I'll be at the Midnight Code Cup finals in Belgrade and I already have some interviews lined up (and might film some other cool stuff as well). Let me know what you think of this new format and how many you got right :)

Thanks Pajaraja, milisav and stefanbalaz2 for participating :)

A lot of you guessed correctly that the next guest is pashka! He's the 2004 ICPC World Champion and World-Class Algorithm teacher, with a free course that has helped tens of thousands of people online.

We talked about about his 30+ year experience in Competitive Programming, how he keeps in good form for so long, how he became a teacher and he gives us some tips for Competitive Programming from a teacher's perspective.

I hope you'll enjoy it! Let Pavel know if the comments how he has helped you on your CP journey, I'm sure he'd like to know :)

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg
• m

  aroonrk
  : https://youtu.be/HFK9gqur93Y

P.S I don't have new podcasts planned for the very near future (1-2 months, though something might pop up!). We'll be experimenting with some other formats that hopefully give you value. Let me know which of these sound interesting (you can choose multiple if you like them):

1. Onsite Competition Vlogs
2. Stories/Lore from the world of competitive programming (personal and global)
3. Tips from a coach
4. Competitive programming challenges, quizzes, games...

As promised, here is the second interview from Japan — with one and only Riku maroonrk Kawasaki. You might know him from often being in the top 10, but he's also writing and coordinating some of the best contests in the world — the AtCoder Grand Contests and World Tour Finals. Apart from this, he is also an IOI and ICPC WF gold medalist!

We talked about about his criteria for great problems, being part of Japan's golden IOI generation and working at AtCoder. If you want to see these interviews before I post them here on Codeforces, make sure to subscribe!

I hope you'll enjoy it!

Our previous podcasts in case you missed them:

• Pajaraja
  : https://youtu.be/ax4xjGBda-o
• R

  adewoosh
  : https://youtu.be/F7sTxKfx5VU
• E869120
  and
  square1001
  : https://youtu.be/AZY1zXFvSbg

PS. I recorded the next episode a few weeks ago. Wanna guess the guest? Here are some hints:

• He's a past ICPC World Champion — but not in the last 10 years!
• On IOI he won a silver medal.
• He's participating in the 2025 Universal Cup Finals.

Winner gets to see the interview a bit before it's released next month :)

Edit. Yep, it seems I made it too easy! Next month's guest is pashka. For guessing correctly, rm-rf, Think_Only_Once and TimDee will get to see it first :)

After sitting down with Pajaraja (blog) and Radewoosh (blog), I got the chance to go to Japan (more videos about this to come!) and talk to some very cool people there.

The first interview is with the Yoneda brothers, square1001 and E869120, known for their extensive contribution to the competitive programming world — setting 4 IOI tasks (and many other contests), writing many guides on preparation. Of course, they are incredible programmers as well — together, they have an ICPC World Finals medal and separately, 3 IOI Gold medals and the ICPC Challenge Championship trophy. Interestingly, Masataka also wrote three books about math and programming, which we discuss in the interview.

We talk about their origin story, competing together and against each other, brotherly rivalry and everything in between. There'll be much more content soon (some podcasts and some totally new), if you'd like to see it subscribe :)

I hope you'll enjoy it!

I had the chance to sit down and talk to a legend — Mateusz Radecki Radewoosh. Here's a little treat while you're waiting for system testing link in case the embed doesn't work:

This is a series of interview I'm doing called Competitive Programming Podcast. You can check the last one on our channel. I already recorded two more interviews with legends which will come out in the next couple of months. If you don't want to miss them you can subscribe :)

Recently, I've had a wish to sit down with great competitive programmers that I find interesting and pick their brains about different topics. For the first iteration, I talked to my good friend Pajaraja, as I'm sure he's unknown to many of you, but he's well known in Serbia as one of the best — both problemsetters and competitive programmers (and especially competitive mathematicians).

Some of his accomplishments:

• 2x Gold medalist at the International Mathematical Olympiad (as well as a Silver medalist)
• Silver medalist at the International Olympiad in Informatics
• 3x ICPC World Finals participant (including a recent 15th place in Luxor)
• IOI Problemsetter (IOI 2021 — Fountain Parks)
• Google HashCode finalist
• many more!

We discuss differences between competitive math and competitive programming, problemsetting, his motivation, pressure and success among other things. Link in case the embed doesn't work.

We prepared two versions (with same tasks) — one is sorted (according to our thoughts), with subtasks (for individual practice), the other is shuffled, with ICPC scoring — this version is great for people practicing for team competitions. You can find both versions in this group. If enough people do it and like it, we can do a follow up problem analysis :)

Even if you don't have the time to watch our discussion, I highly recommend you check out the problemset!

Our team qualified for ICPC World Finals 2022 on November 21st, 2021 at SEERC. We will participate at the World Finals this Thursday, April 18th, 2024 in Luxor. We've been thinking how much time has passed since then and about all the things that occurred since. Here are a few of my notes:

• 879 days have passed, or 2 years 4 months and 28 days
• Got engaged and married
• My rating dropped by 116 points
• I gained 35kg
• My teammates moved into two different countries to study
• Novak Đoković won 4 Grand Slams, 3 Masters and 2 ATP Finals
• Two major international wars were (re)started
• Messi became World Champion
• India became most populous country
• Queen Elizabeth died
• Everybody started caring about AI again

I'm sure many of you have the same experience as us, leave any cool facts in the comments :)

Best of luck to everyone, especially those not directly competing with us!

P.S. Don't take this as a dig at ICPC — while I dislike this long pause, some of the stuff has been really bad luck on their side. I'm thankful to finally have the opportunity to participate at this grand event. One thing they could fix is not knowing whether we qualified until last August...

Since the second round of this season of COCI (Croatian Open Competition in Informatics) was held last saturday, here is the continuation in the series of COCI appreciation posts (I will post one after each COCI round, so six in total!). For my coaching, I went through all COCI contests since 2006 to gather tasks and selected some of my favorite ones.

Notes

• Check out the first post for notes about the process and the problemset.
• There are 9 tasks in this problemset since I accidentally forgot to put one task (Zoo) last time, so it's included now.

Tasks

A: 2016/2017, Contest 5: Ronald

Author: Adrian Satja Kurdija (satja)

Tags:

Note:

Difficulty range: 1300-1500

B: 2011/2012, Contest 2: Kompići

Author: Adrian Satja Kurdija (satja)

Tags:

Note:

Difficulty range: 1300-1500

C: 2013/2014, Contest 2: Putnik

Author: Adrian Satja Kurdija (satja)

Tags:

Note:

Difficulty range: 1500-1700

D: 2020/2021, Contest 5: Planine

Author: Daniel Paleka and Paula Vidas (dpaleka,paula)

Tags:

Note:

Difficulty range: 1700-1900

E: 2013/2014, Contest 2: Linije

Author: Domagoj Ćevid

Tags:

Note:

Difficulty range: 1900-2100

F: 2019/2020, Contest 1: Trobojnica

Author: Daniel Paleka (dpaleka)

Tags:

Note:

Difficulty range: 2100-2300

G: 2014/2015, Contest 4: Stanovi

Author: Mislav Balunović (mislav)

Tags:

Note:

Difficulty range: 2100-2300

H: 2016/2017, Contest 6: Sirni

Author: Domagoj Bradač (DBradac)

Tags:

Note:

Difficulty range: 2200-2400 (my guess :) )

Bonus task (since I forgot it last time):

2019/2020, Contest 1: Zoo

Author: Ivan Paljak (ipaljak)

Tags:

Note:

Difficulty range: 2200-2400

I hope you find these tasks useful!

Since a new season of COCI (Croatian Open Competition in Informatics) started last saturday, here is the first in a series of COCI appreciation posts (I will post one after each COCI round, so six in total!). For my coaching, I went through all COCI contests since 2006 to gather tasks and selected some of my favorite ones.

Notes

• I skipped a lot of the really hard tasks because they weren't useful for my students. I kept a list of these tasks, if someone wants it, they can PM me. Also, I only considered COCI, not COI. This current season is not being considered.
• There are many great tasks outside of the 48 shown (throughout the series), so it's worth it to go through other tasks as well. I have selected just my favorite ones.
• These tasks are maybe not always the most innovative, I have selected the tasks that are most useful for coaching and learning new ideas, so for people who already know the idea, the difficulty might be much lower. Still, there are some really interesting tasks.
• You can do these tasks either individually or as a virtual contest. There is a lot of them, so I wouldn't recommend less than 3h.
• The notes are meant for coaches, to know if they can use that task for a lecture that they are preparing. They can also serve as hints for competitors (but sometimes they just give out the solution). Both the tags and the notes should be considered spoilers.
• The given difficulty ranges might be completely wrong as I might be out of touch with the easier grades, they are just given as a loose guide.
• Most solutions can be found on the official site by looking up the appropriate season and contest. If not, I'll try to provide the best resource I can.
• Let me know if you know some missing info (author/author cf handle).

Tasks

A: 2015/2016, Contest 4: Deathstar

Author: Dominik Gleich (Dgleich)

Tags:

Note:

Difficulty range: 1100-1300

B: 2013/2014, Contest 1: Organizator

Author: Domagoj Ćevid

Tags:

Note:

Difficulty range: 1300-1500

C: 2017/2018, Contest 5: Birokracija

Author: Ivan Zufić (falanga)

Solution (thanks bmerry)

Tags:

Note:

Difficulty range: 1400-1600

D: 2009/2010, Contest 7: Svemir

Author: Goran Žužić (Zuza)

Tags:

Note:

Difficulty range: 1600-1800

E: 2014/2015, Contest 6: Kratki

Author: Dominik Gleich (Dgleich)

Tags:

Note:

Difficulty range: 1600-1800

F: 2019/2020, Contest 6: Index

Author: Marin Kišić (mkisic)

Tags:

Note:

Difficulty range: 2100-2300

H: 2016/2017, Contest 1: Vještica

Author: Dominik Gleich (Dgleich)

Tags:

Note:

Difficulty range: 2200-2400

I hope you find these tasks useful!