ko_osaga's blog

Facebook Hacker Cup 2017 Final Round
By ko_osaga, history, 7 years ago, In English

Round : https://www.facebook.com/hackercup/scoreboard/1799632126966939/

Time : https://www.timeanddate.com/worldclock/fixedtime.html?msg=2017%20Facebook%20Hacker%20Cup%20Finals&iso=20170614T1330&p1=234&ah=4

List of Participants : http://codeforces.me/blog/entry/50089

(Note that actual participants slightly differ from that list)

I'm pretty flattered for my first ever onsite competition (beside IOI) :D Good luck and have fun!

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7 years ago, # |
  Vote: I like it +33 Vote: I do not like it

Good luck!

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7 years ago, # |
  Vote: I like it +45 Vote: I do not like it

ko_osaga dotorya kriii good luck!

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7 years ago, # |
  Vote: I like it +46 Vote: I do not like it

My sad story on D :

I wrote a solution which passed against naive solution for all small random cases. So I tried to submit it. After downloading input, I found that my call stack had been overflowed by simple recursive dfs. I failed to fix it in 3min and my submit button was expired...

After contest, it seems that this was also a case for scott_wu and RomaWhite

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    7 years ago, # ^ |
      Vote: I like it +23 Vote: I do not like it

    Same thing happened for me as well :-(

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    7 years ago, # ^ |
      Vote: I like it +19 Vote: I do not like it

    If you are using g++, you can try g++ -Wl,--stack,268435456 A.cpp -O2

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      7 years ago, # ^ |
      ← Rev. 2   Vote: I like it +48 Vote: I do not like it

      Windows only. On Linux stack is regulated by user's configuration, not executable itself, so you have to call something like ulimit -s unlimited before running the solution.

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    7 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Some things never change, link.

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      7 years ago, # ^ |
        Vote: I like it +18 Vote: I do not like it

      FHC 2017 was my first hacker cup in my life :D (but yeah, I experienced simillar problem in IPSC 2016)

      That ulimit thing is cool. My 3 minute googling didn't went that far. Sounds that it's sth worth to remember

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7 years ago, # |
  Vote: I like it +87 Vote: I do not like it

Final Results:

  1. Petr
  2. dotorya
  3. LHiC

Congratulations!

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    7 years ago, # ^ |
      Vote: I like it +13 Vote: I do not like it

    Nice! Is there a photo of complete results available? The public scoreboard doesn't seem to unfreeze any time soon.

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      7 years ago, # ^ |
        Vote: I like it +24 Vote: I do not like it

      https://goo.gl/photos/CQG2hQMhaDAgqHF49

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        7 years ago, # ^ |
        ← Rev. 3   Vote: I like it +20 Vote: I do not like it

        Thanks!

        I'm curious why there are so much fails on the second problem. Is there an evil testcase that many have missed?

        Edit: And of course, congratulations on yet another victory!

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          7 years ago, # ^ |
            Vote: I like it +57 Vote: I do not like it

          It's actually quite tricky. I made a logical mistake (did not notice that vertex cover can be smaller than both parts), did not notice that fox locations are banned, and also made a silly bug in code. Unfortunately, all those issues combined led to passing samples, while each one by itself won't :)

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            7 years ago, # ^ |
              Vote: I like it +20 Vote: I do not like it

            After the contest I thought this problem was very tricky. The logical mistake was very tempting, and the samples didn't catch that (at least I thought so).

            Now I don't know why there were so many failures. Did they manage to find various unlucky combinations of bugs that pass samples?

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              7 years ago, # ^ |
                Vote: I like it +15 Vote: I do not like it

              The 5th sample was designed to break that incorrect approach (just using the 2-coloring per component). However, as Petr described, a number of contestants used that approach combined with various different implementation bugs, which just happened to make it pass the samples :(

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      7 years ago, # ^ |
        Vote: I like it +9 Vote: I do not like it

      It unfroze. :)

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7 years ago, # |
  Vote: I like it +14 Vote: I do not like it

What happened to Errichto?

The announcer doesn't go through his submissions in the scoreboard reveal. According to this link he got 21st place but scott_wu is shown 21st in the scoreboard reveal and Errichto is completely vanished.

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    7 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    He didn't participated in onsite competition, so his submission is unofficial

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    7 years ago, # ^ |
      Vote: I like it +35 Vote: I do not like it

    He may be good in problem solving however getting his life together seems to be NP-complete for him :P

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7 years ago, # |
  Vote: I like it +16 Vote: I do not like it

Anyone willing to take bets on whether this year's prizes will be ever paid out? Although I haven't found corresponding public announcement, the video from closing ceremony clearly shows big checks that are awarded to the winners.

Update on last year prizes (March 2016): there is no good information about any progress since the finals. The last action, according to the information I have, was made in January: a dedicated person should had been assigned to prizes payout. I don't know whether that happened.

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    7 years ago, # ^ |
      Vote: I like it +15 Vote: I do not like it

    Similar question, has anybody received t-shirt for finishing in the top 500 from this January?

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    7 years ago, # ^ |
      Vote: I like it +10 Vote: I do not like it

    To give an "update" on the cited post, the FHC people are making some efforts to get 2015 prizes (and some 2014 prizes, I think) paid out, but seem to be hitting some sort of wall internally (with the finance team or whoever).

    So I agree: it's anyone's bet... :)

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      7 years ago, # ^ |
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      but seem to be hitting some sort of wall internally (with the finance team or whoever).

      I have the same impression about 2016 prizes.

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      7 years ago, # ^ |
        Vote: I like it +14 Vote: I do not like it

      They'd sent me some tax forms after the 2015 Finals, but I couldn't understand what the form said at all and I also guess they sent wrong forms to me (it required to write my company's name rather than my individual name).

      For Google's reimbursement & prizes, it was very easy to fill what they need, because their forms are not government's tax form but just a Google form.

      I think Hacker Cup officials must do something like that.

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        7 years ago, # ^ |
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        Well, I think I got my 2015 money, like, a year ago. As for as the wrong form, I complained to them about this and then they replied with the form for individuals. Then, filling this form was not effortless, but it was at least doable.

        Yeah, GCJ reimbursement process is way more pleasant.

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          7 years ago, # ^ |
          ← Rev. 2   Vote: I like it 0 Vote: I do not like it

          Thank you for the update! Nice to hear that there was some progress with 2015.

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7 years ago, # |
  Vote: I like it +8 Vote: I do not like it

How can I receive my T-shirt for previous year? Facebook tried to send it at first but didn't succeed, after that I wrote the guy responsible for the delivery, and he said "Of course we'll send it shortly", and no updates or response after that.

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