An Interview with rng_58, Our New SRM Coordinator

The 2011 TopCoder Open is over. Makoto Soejima, with his famous handle rng_58, won the Algorithm Track. He successfully defended his champion title after winning last year’s TCO. An impressive two-streak win!

Who would ever think that the TCO11 Championship Round was his last SRM? Yes, starting from SRM 520, he became a new algorithm coordinator, replacing Ivan Metelsky (mystic_tc).

Of course, this is a very interesting promotion. Unfortunately, this happened so fast that we couldn’t actually know what has happened behind the scene. So, I contacted Makoto and “interviewed” him with some questions. It was actually possible after we prepared SRM 520 together, with me as the writer and Makoto as both the tester and the new coordinator.

Here it goes…

TCO11 Algorithm Victory

This was my first time to watch TCO Algorithm Finals in the Arena. It was very exciting experience. I entered the only room in the Arena together with the other online spectators. It was fun to be able to chat there; the finalists won’t see our chats.

The finals happened with a strong tense. All three Japanese finalists started with the 1000 first, while the other started with the 250. The Easy seemed not to be easy enough as it took quite a lot time for most coders to solve (except ACRush). Seven coders eventually submitted the 250, with only five of them survives the system tests. Five coders submitted the 500, all passing the system tests. It turned out that solving the Easy and the Medium was not enough to win TCO, as rng_58 finally submitted the 250 and 1000, passed all system tests, and won the competition!

Petr wrote a nice live coverage for the finals in his blog.

fushar: You did the finals with a 1000-250 strategy. What’s the reason behind that strategy?

rng_58: I checked the results of old finals, and it turned out that most winners solved 1000.

fushar: I saw that all three Japanese finalists (lyrically, [[iwi]], and you) used the same strategy. Was that a coincidence?

rng_58: Yes, it was a coincidence. I didn’t know their strategies.

fushar: How was your feeling during the challenge phase? Were you confident that your 1000 wouldn’t get challenged?

rng_58: I wasn’t confident because I didn’t have time to test my 1000.

fushar: What did you think about the problems? Were they as nice as the previous year’s?

rng_58: The problems were more trickier than previous year’s.

fushar: You won TCO Algorithm Track for the second time, with a very dramatical win! How did it feel to have managed to defend your champion title?

rng_58: I was surprised!

Becoming an SRM Coordinator

After the finals, my SRM problemset proposal was accepted as SRM 520. It was the third time I wrote problems for SRMs. Luckily, the SRM was the first SRM Makoto would manage as the new coordinator! It was a very nice experience working together with him to prepare an SRM.

fushar: How exactly did you finally join TopCoder? Did TopCoder admins approach you or did you apply for an admin?

[[rng_58]]: It was August 25th. TopCoder will organize more marathon matches. mystic_tc doesn’t have time to organize both matches, so he invited me to admin.

When I entered the Arena with “writer” account in SRM 520, I still saw mystic_tc and no “tester” account.

fushar: So, are you taking all mystic_tc‘s responsibility for organizing SRMs? How about mystic_tc, then?

[[rng_58]]: He will organize marathon matches and test all algorithm matches. So, in each SRM, there will be the writer, me, and him as the tester. There will be also a person checking for wording, currently PabloGilberto. Furthermore, the email address used to send problem proposals is now

fushar: What do you think about mystic_tc as the previous algorithm coordinator?

[[rng_58]]: He did a good job. He always chose interesting problems.

fushar: By becoming a TC admin, you can no longer compete in SRMs as the red-rated rng_58. Does that matter to you?

[[rng_58]]: I will return after I quit an admin.

fushar: Tell me something you don’t like about past SRMs, before you joined as an admin (and maybe the possibility to improve them).

[[rng_58]]: I liked almost everything about past SRMs.

This is for them who likes to write problems but hard to get them accepted for SRMs.

fushar: Give us some tips for problem writers to have their problems accepted for SRMs more easily.

[[rng_58]]: Write a problem that requires an interesting idea and have appropriate difficulty.

fushar: You have already organized your first SRM as a coordinator, with me as the writer. How was it? Did you enjoy that?

[[rng_58]]: I enjoyed that. It was hard for me to use a lot of tools to organize SRMs.

Thanks, Makoto! 🙂

fushar: What is the story behind the choice for [[rng_58]] handle? Does it relate to [[iwi]]? I thought you would use rng_tc or mystic_58 😛

[[rng_58]]: It’s because [[]] looks nice. If [[iwi]] become an admin, his handle will be [[[[iwi]]]].

fushar: How about your -1 rating? You are the lowest-rated coder in TopCoder!

[[rng_58]]: I didn’t know I will get -1 rating. Probably it’s a bug. Even -1 couldn’t get -1 rating 🙂

fushar: Describe what you feel about TopCoder SRMs in just two words.

[[rng_58]]: “TopCoder SRMs” 😛

So, from now on we have a new SRM coordinator, Makoto Soejima. I hope he will improve the quality of future SRMs. I hope SRMs will have more interesting and original yet solvable problems. We’ll see!

P.S. I also hope someday I’ll edit this post and change my handle color into red.

About Ashar Fuadi

Ashar Fuadi is a competitive programmer from University of Indonesia. He loves to code, especially for TopCoder SRM, Codeforces, and ICPC.
Follow Ashar on Google+ and Twitter.


  1. […] was the first SRM [[rng_58]] (Makoto) moderate as the new algorithm coordinator, after successfully winning TCO 2010 and TCO 2012. This was the first match after TCO 2012 finals. […]

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