hmehta's blog

TCO19 Algorithm Round 1A
By hmehta, history, 6 years ago, In English

The first Algorithm Competition Online Rounds of the 2019 Topcoder Open has arrived! Round 1A will be held on Saturday April 20, 2019 at 12:00 UTC -4.Registration is open for the round and closes at 11:55 UTC -4, April 20 2019.

Did you win an Automatic Berth a.k.a Bye for Round 1? Check out the list of members who won an automatic berth to Round 2 here.

How many will qualify? The 750 highest scorers from each Round 1 will win a spot in Round 2 of the Algorithm Competition. Note: To be eligible to advance from an Online Round Match, the Competitor must finish the Match with a point total greater than zero.

There will be one more Round 1 — Round 1B on Wednesday, May 1, 2019 at 07:00 UTC -4.

Best of luck to you in the Arena! -Topcoder

Update: Match Summary and Editorials: https://www.topcoder.com/blog/2019-topcoder-open-algorithm-round-1a-editorials/

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Comments Comments (22)
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6 years ago, # |
  Vote: I like it +28 Vote: I do not like it

I think you need to mention positive scores are needed to qualify..

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    6 years ago, # ^ |
      Vote: I like it +38 Vote: I do not like it

    And it also looks like the only thing need mentioning! If you have positive score, you will be in top 750...

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6 years ago, # |
  Vote: I like it +3 Vote: I do not like it

Just received an email saying I’ve won a bye to Round 2. Will there be another email for those who got to Round 4 (or even to the Finals) through the SRM point system in one of the 4 online stages? I imagine people who advanced through that rule won’t be eligible to participate in Round 2 despite the bye, right?

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

Who is the writer again?

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    6 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    That would be me.

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

      Bonjour! Loved your sin(t) codeforces rating graph! another maxima expected after few contest. :)

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

Is it rated?

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

Will this count towards the points for TCO regionals?

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

1000 point problem's precision issues were frustrating, otherwise the round was good!

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    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it +32 Vote: I do not like it

    That's because the intended way was to avoid any floating-point number calculations until the very end?

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

      I wanted to do that but don't the bounds mean it can overflow 64-bit integers?

      If the percentages are set to 99, you end up (almost) doubling up to 100 times, which seems like it should be too much.

      Maybe the idea is that such cases will never arise because they don't have a unique answer... but it doesn't seem obvious that this is true.

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        6 years ago, # ^ |
          Vote: I like it +16 Vote: I do not like it
        Spoiler
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          6 years ago, # ^ |
            Vote: I like it 0 Vote: I do not like it

          You're right — I forgot to think about the average when I was doing the estimations.

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    6 years ago, # ^ |
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    Indeed, the intended solution was to use integers only and since I expected many people wouldn't do that, I expected the problem to provide plenty of challenge opportunities. Apparently, creating a test wasn't that easy, thus most solutions failed on the System Test.

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    6 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    I managed to pass this problem by calculating everything in cents, so only integers needed. To round a real number to the nearest int, I used int(x + 0.5).

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

      I had a separate divide function that rounded numbers fully in integers.

      auto divide = [](li a, li b){ 
    if (a % b * 2 >= b) 
        return a / b + 1; 
    return a / b; 
};
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6 years ago, # |
  Vote: I like it 0 Vote: I do not like it

So, what is best solution for 250 problem?

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