rpeng's blog

By rpeng, history, 4 years ago, In English

If you still need to gain things from contests (e.g. I got into contests in high school mainly because Waterloo promised to pay my undergrad tuition if I bring some metals, and did WF so I could go to the US): unless the problem setters have very poor academic integrity and are also very very very good friends with you, there is no such thing as good or bad problems: there are just problems that you lose to, and problems you don't lose to. I'm saying this because the back-end of contest organization is usually held together by spit-and-glue, so to make it through such system, one essentially has to prepare for worst-case scenarios.

If you are getting into contest organization, the one sentence criteria I like to use is "achieve the intended score distribution, while maximizing the amount of additional information that one needs to communicate to someone who didn't solve the problem so they solve it". This in my experience minimizes the amount of post-contest complaining, and gives contestants more faith in the system. There are two exceptions to this:

  • Knowledge based problems: I like the idea of having a syllabus e.g. the IOI version, because otherwise the escalation is towards turning research papers into problems. Should such escalation occur, you (or your coach) need to be very very very good friends with the problem setters to even have a chance vs. such problems: there are just too many 20~40 line algorithmic gems that took way too long for people to figure out. I actually don't mind what the syllabus consists of, as long as it's learnable in a reasonable amount of time (6-10 months), and clearly communicated.

  • Overlaps with math contests: by now, there has been many on-site programming contest problems that were only solved by contestants w. IMO experience. So I've more or less accepted that such overlaps are inevitable. At the end of the day, I feel it's an issue with the ease of problem setting: there are just way more math contest problems out there that can converted into programming (e.g. most of Tugor non-geo probs). Maybe here the solution is to have programming contests that are explicitly more math focused, to double as math contest training as well. Here I find it a bit funny that attempts at making math contest online judges has yet to work out, while programming contestants seem to get better and better at math contests.

Let the flame war begin.

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By rpeng, history, 5 years ago, In English

For context, please refer to this thread. TLDR: over the past four years, Georgia Tech has always placed second in our ICPC regional contest, and did not advance to the ICPC World Finals due to the region repeatedly being allocated only one slot.

I would like to try a thought experiment: are there CF users with ratings 2400 or higher, are ICPC eligible for WF20 (based on extrapolations of the criteria for WF19), and would be interested in spending a year at Georgia Tech from mid-August 2019 to May 2020? The tentative plan for funding is at the Masters student rate (full tuition coverage, plus a stipend of about 1500 USD / month), with other responsibilities being TAing for algorithms courses and conducting research.

If you are interested, please email me at [email protected] with your CF id, and ideally, a short CV. Please also note that while I'm extensively involved with algorithmic problem solving competitions, my role with the GT ICPC team is minimal: the main coach/organizer is fahrbach.

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By rpeng, 11 years ago, In English

The world finals trip this year started early for the Carnegie Mellon University (CMU) team with a visit to Saratov. As I'm typing this, the three contestants Nathaniel Barshay (nbarshay), Yan Gu (henryy), and Jonathan Paulson (jonathanpaulson) are happily stress testing the SGU contest server with WAs, TLEs, RTEs, and of course the occasional AC :-).

CMU1, from closer to farther: Nathaniel Barshay, Yan Gu, and Jon Paulson

In my experiences as a contestant and as a coach, the North American -> Europe time difference is one of the harder ones to adjust to. To avoid repeating what Harvard did during the dress rehearsal at WF`12 (taking a nap), the CMU head coach Danny Sleator (Darooha) looked into traveling a few days earlier. We were very fortunate to have gotten into contact with Mike Mirzayanov (MikeMirzayanov, no introduction needed), who made arrangements for us to train with the teams from Saratov State University for about a week.

Mike in the coach's lair at the SGU programming contest training center.

After a few days of contests, problem discussions, and excursions around Saratov, the jet lag slowly went away and everyone started enjoying themselves more. I feel that the CMU team is also now in a much better position to deal with the challenges of the upcoming World Finals. The regular practice and group discussion afterwards allowed us to train at a pace that's quite rare back home. Of course, trying for a medal at WF is always an uphill battle.

Group discussion of problems

Solution presentation by Ivan Fefer (Fefer_Ivan)

Competing against teams in the same room proves to be a very different experience than practicing using virtual scoreboards. On the other hand, talking with other contestants right after the contest was immensely useful for understanding the solutions quickly, and seeing what could have been done differently. So far, I'm glad to report that CMU1 has been able to hold their own against SGU1 and SGU2. The students from SGU have also proven to be formidable opponents both on the ping-pong table and in the water.

Nate Barshay (nbarshay) vs. Edvard Davtyan (Edvard)

CMU1 and SGU2 on the Saratov bridge walking back from Engels.
Downtown Saratov is directly ahead, and Saratov beach is on the right.

On Saturday we will begin our travel towards St. Petersburg. This means that I only have a little more than a day left in Saratov. As usual, before the contest one always wishes that they had more time to train. This is especially the case this time since we have only explored a few places in the city. However, I have a feel that future travels will take me back to Saratov, and I look forward to visiting again.

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