iaNTU's blog

By iaNTU, history, 18 months ago, In English

Hi, I'm a contestant of 2019 Bangkok Regional contest, which have just finished the practice session today.

During the practice session my teammates found some strange behavior of the judging system. Below are the list of issues we found.

  • The order of the problems on the scoreboard was randomized and there's no problem number on it, thus neither the contestant nor the coach could know the real order. For example, the problem order on the scoreboard in the practice session was actually CAB.
  • CE code submissions were judged as RE, which contributed to the penalty. (The judge replies that it might be fixed though.)
  • The sample testcase of problem B in practice session was wrong, and when asked the judge responded "read the problem statement".
  • The input description of problem C said that the string Y would be given in reverse, while it's not.
  • Some team asked about the stack size, and the judge replied that they can't let us know.

This is our first year participating in ICPC contests, so I don't know whether this is common >///<.

 
 
 
 
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18 months ago, # |
  Vote: I like it +198 Vote: I do not like it

Assuming that you don't exaggerate:

Don't trust the organizers and next time test things like stack size yourself during the practice session, in order to understand what verdict you would get. And tomorrow (during a real contest), don't be stuck on one problem, there might be something wrong with it. Optimize your behavior without assuming that the contest is well prepared, that's a skill too :D

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18 months ago, # |
Rev. 2   Vote: I like it +15 Vote: I do not like it

I participated in national round at the same place before, today practice session is much better than the national round, I think. The issues in national round are as followed.

  • Judging system didn’t accept any solutions for 1-2 hours. (The contest was extended by 30 minutes because of that.)

  • In many problems, we had to wait like 10+ minutes for the result.(It was faster when the contest was almost finished.)

  • The internet was broken nearly the end of the contest. We almost cannot submit one task in time.

  • Maybe I was too bad at Ubuntu, so I asked the staff how to copy input from pdf and paste in terminal. Surprisingly, the staff didn’t know either, so we have to do input manually. (However, they figured how to do it later and told us.)

  • The order was randomized as well. I don’t know the reason too.

Gladly, there was no problem with statements in that round. I hope there are no issues like these tomorrow.

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18 months ago, # |
  Vote: I like it +12 Vote: I do not like it

The order of the problems on the scoreboard was randomized

They (Bangkok regional organizer) did this shit 5 years ago and I'm surprised that nothing has been done given how unnecessarily annoying it is for the contestants.

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    18 months ago, # ^ |
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    It's ridiculous. Can't they follow the behavior and rules of all other competitions, organized by people with big experience?

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      18 months ago, # ^ |
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      What’s funny here is that Thailand almost always host a regional every year (hosted WF 2016 too) and this only happens in Bangkok. It’s not like they are inexperienced or something. You are free to experiment new format with your local contests. Regionals serve as a way to qualify for WF and one should know better to follow the WF format.

      By the way, did I mention that it was possible to figure out the exact problem order in the scoreboard using JavaScript? If you’re not competent enough, perhaps don’t try to screw things up for others with your so-called invention?

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    18 months ago, # ^ |
      Vote: I like it +38 Vote: I do not like it

    IIRC the last two Thailand Regional contests were hosted in Nakhon Pathom by ICT Mahidol and it went smoothly (no stupid shenanigans or technical fuck-ups). I did not recall any complaint about the 2016 contest either (hosted by Chulalongkorn, also the host in 2014 and this year). So I'm very surprised they decided to go back from being one of the better regional contests to this.

    Sucks that there are a lot of strong teams competing in Bangkok this year (Tokyo, Seoul, NTU Taiwan, NUS just to name a few). They don't deserve this.

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      18 months ago, # ^ |
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      Well, in 2017 there were some problems with Java that made the judges to let all contestants to shut down their screens and work on paper in the mid of the contest for around 15min, I did not know the exact problem but I guess it was related to Java compilation or execution on jury machine.

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      18 months ago, # ^ |
        Vote: I like it +38 Vote: I do not like it

      Yeah :D I don't understand why strong teams like Tokyo, Seoul, NTU Taiwan don't go to Vietnam regional instead. We have:

      • better problems (in recent years)
      • correct & strong test cases
      • high quality problem statement
      • usually no technical issues (we host contests on Kattis)

      You can check our past contests here:

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        18 months ago, # ^ |
          Vote: I like it +23 Vote: I do not like it

        Small prize.

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        18 months ago, # ^ |
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        Oi, let me have some chance to qualify, don't you? ><

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18 months ago, # |
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I think somehow they shuffled the order of the problems so that the participants can't decide the easy problems through the scoreboard. Based on here

About the stack size and computing speed, I think it's your thing to test it during the practice session.

Well I guess the rest is decided by the hosting university.

Good luck!

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    18 months ago, # ^ |
      Vote: I like it +47 Vote: I do not like it

    Wtf, why would you hide stack size and tell people to binary search it themselves, or just guess? Why put constraints in the statement at all, right?

    Showing which problems to solve is a good thing because there are many teams and weakest ones who can only hope to solve 1-2 easiest problems. It becomes much harder if you have 12 problems and have no idea about the difficulty. If you want a contest with a completely new format and rules, just hide the leaderboard or show only the number of solved problems, but it will change the contest significantly and shouldn't be used as regionals for ICPC.

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      18 months ago, # ^ |
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      Probably the scientific judges don't know about the technical issues or site environment-related things (stack size, speed, OS). So you have to figure it out by yourselves. Last regional (not Bangkok) I attended, showed compile flag and if I'm not mistaken they said the stack size was set to default, but not quite sure how big.

      Showing which problems to solve is a good thing because there are many teams and weakest ones who can only hope to solve 1-2 easiest problems. It becomes much harder if you have 12 problems and have no idea about the difficulty. If you want a contest with a completely new format and rules, just hide the leaderboard or show only the number of solved problems, but it will change the contest significantly and shouldn't be used as regionals for ICPC.

      I agree.

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        18 months ago, # ^ |
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        Nobody says that scientific judges should know that. There should be somebody working on the technical side though. Organizing a contest isn't just about preparing algorithmic problems.

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18 months ago, # |
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Yes, it's kinda common for ICPC contests to have some pathetic, embarassing fuckups. Selection guided by politics, contest environment not working, broken problems, stupid rules. There are some blogs here about it.

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18 months ago, # |
Rev. 2   Vote: I like it +53 Vote: I do not like it

CE code submissions were judged as RE

When I was in Nakhon Pathom, TL code submissions are judged as AC, so don't worry.

Anyway, stack size is 1MB.

Plus. I recall similar issues on the scoreboard, but it was fixed in the main contest, at least after a while. I hope it to be similar this year too.

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18 months ago, # |
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Anyone have scoreboard link?

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18 months ago, # |
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The big problems I see here are the incorrect sample inputs (there is no excuse for this in problems prepared using modern tools and judge systems) and wrong input specifications (unfortunately not completely avoidable, and mostly a function of too few, poorly-coordinated judges not checking the problem set carefully enough.) If either of these affected the results, your coach could try complaining to the site director, RCD, or above. But unfortunately the ICPC bureaucracy is not known for a surplus of either transparency or receptiveness to constructive feedback...

Regarding CE being penalized as WA, and the random scoreboard: these might be annoying but ICPC gives regions very wide latitude to run the contests however the want, including strange rules like these. At least they are fair (if explained to everyone before the contest starts...)

Regarding stack size: the judge may honestly just not know, since the stack size depends on factors like the system ulimit, compiler toolchain, platform, etc. Also even knowing the stack size won't help you unless you also know the size of the stack frame which will be platform and compiler-dependent. I don't think the NA ICPC contests usually provide stack information either (for instance https://open.kattis.com/help/cpp makes no mention of stack size), but Errichto gives good advice: you can use the practice time to test the size for yourself.

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18 months ago, # |
Rev. 4   Vote: I like it +24 Vote: I do not like it

Too much math problems... More astonishing, problem G is actually from IMO this year. That's why we got the first AC at this problem in the contest lol. https://artofproblemsolving.com/community/c6h1876772p12754128

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    18 months ago, # ^ |
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    Where I can find the problemset?