maroonrk's blog

By maroonrk, history, 34 hours ago, In English

We will hold AtCoder Regular Contest 127.

Please note the unusual start time (1 hour earlier than usual).

The point values will be 300-500-500-700-800-1000.

We are looking forward to your participation!

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By maroonrk, history, 8 days ago, In English

We will hold AtCoder Regular Contest 126. Please note the unusual start time (1 hour later than usual)

The point values will be 300-400-600-600-800-1100.

We are looking forward to your participation!

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By maroonrk, history, 5 weeks ago, In English

We will hold AtCoder Regular Contest 125.

The point values will be 300-500-600-700-800-900.

We are looking forward to your participation!

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  • Vote: I like it
  • +165
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By maroonrk, history, 2 months ago, In English

We will hold AtCoder Regular Contest 124.

The point values will be 300-400-500-700-800-900.

We are looking forward to your participation!

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By maroonrk, history, 2 months ago, In English

We will hold AtCoder Regular Contest 123.

The point values will be 300-400-600-700-700-1000.

We are looking forward to your participation!

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By maroonrk, history, 3 months ago, In English

We will hold AtCoder Grand Contest 054. This contest counts for GP30 scores.

The point values will be 300-800-800-1000-1200-1800.

We are looking forward to your participation!

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By maroonrk, history, 3 months ago, In English

After the last ARC, one participant pointed out that the result is WA when the error is precisely the same as $$$EPS$$$ (submission).

For example, consider these two outputs: 331997010.50000000000000000000 (the jury output) and 331997342.4970105 (the user output). Their relative error is exactly $$$10^{-6}$$$, so when $$$EPS=10^{-6}$$$, this should get AC.

However, with the current implementation of the doubleCompare function in testlib.h, the result is WA. This is because perturbations in the line 429 (return result + 1E-15 >= minv && result <= maxv + 1E-15;) don't work when the values of result/minv/maxv are large. We made a fix and sent a pull request.

If you believe you were affected by this in the last ARC, please let me know.

That being said, given the popularity of testlib.h and the fact that no one has ever raised this issue, I hope no one was affected by this in the entire history of testlib.h.

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By maroonrk, history, 4 months ago, In English

We will hold Tokio Marine & Nichido Fire Insurance Programming Contest 2021(AtCoder Regular Contest 122).

The point values will be 400-500-600-700-800-1200.

We are looking forward to your participation!

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By maroonrk, history, 4 months ago, In English

As of now, there is no blog, so I'll post this.

How to solve C Large without complex casework?

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By maroonrk, history, 4 months ago, In English

We will hold NOMURA Programming Contest 2021(AtCoder Regular Contest 121).

The point values will be 400-500-500-700-700-800.

We are looking forward to your participation!

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By maroonrk, history, 4 months ago, In English

Please note that the contest time is one hour earlier than the usual time.

We will hold AtCoder Regular Contest 120.

The point values will be 400-400-500-600-700-1600(800).

The full version of the last problem is unusually hard for ARC, so there is an 800-point subtask.

We are looking forward to your participation!

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By maroonrk, history, 4 months ago, In English

We will hold AtCoder Regular Contest 119.

The point values will be 300-500-500-700-800-800.

We are looking forward to your participation!

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By maroonrk, history, 5 months ago, In English

Please note the unusual start time.

We will hold AtCoder Regular Contest 118.

The point values will be 300-400-500-700-800-1000.

We are looking forward to your participation!

Read more »

 
 
 
 
  • Vote: I like it
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By maroonrk, history, 5 months ago, In English

We will hold AtCoder Regular Contest 117.

The point values will be 200-400-600-600-900-900.

We are looking forward to your participation!

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By maroonrk, history, 6 months ago, In English

We will hold AtCoder Grand Contest 053. This contest counts for GP30 scores.

The point values will be 400-700-900-1000-1400-2400.

We are looking forward to your participation!

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By maroonrk, history, 6 months ago, In English

We will hold AtCoder Regular Contest 116.

The point values will be 300-400-500-500-800-800.

We are looking forward to your participation!

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By maroonrk, history, 6 months ago, In English

We will hold AtCoder Regular Contest 115. Please watch out for the unusual start time (1 hour earlier).

The point values will be 300-400-500-600-700-1000.

We are looking forward to your participation!

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By maroonrk, history, 6 months ago, In English

We will hold AtCoder Regular Contest 114.

The point values will be 300-400-600-600-700-900.

We are looking forward to your participation!

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By maroonrk, history, 7 months ago, In English

XXI Opencup GP of Tokyo will be held tomorrow.

I prepared the problems with the help from hos.lyric.

I'll upload the editorial after the contest ends, and also I'll upload the contest to the GYM.

Editorial

GYM

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Announcement of XXI Opencup GP of Tokyo
 
 
 
 
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By maroonrk, history, 7 months ago, In English

We will hold AtCoder Regular Contest 113.

The point values will be 300-400-500-600-800-1000.

We are looking forward to your participation!

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By maroonrk, history, 7 months ago, In English

We will hold AtCoder Regular Contest 112.

The point values will be 300-400-500-600-700-900.

We are looking forward to your participation!

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By maroonrk, history, 7 months ago, In English

Thank you for sharing your opinion on my last blog.

I considered what kind of participants I'd like to honor the most. It was those who have strong confidence and eagerness to take part in contests, not those who care about their rating too much or think like, "what if I can't solve a problem...".

Thus I finally decided to adopt an "open-then-rated" system.

Now it's time to determine the details of the new system. What I'm currently considering is the followings:

  • If you try to open a problem in the first five or ten minutes of a contest, you see a Read Problems button, and pressing it confirms your rated participation.
  • If you are late (or don't press the button in the first five or ten minutes), you are unrated, but still can read and submit to the problems. Also, your name will be shown in the standings and it counts for GP30 scores.

This is a draft, so if you have a concern or an idea, please share it here.

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By maroonrk, history, 8 months ago, In English

TL;DR

What if we introduce the followings:

  • You'll have a register-as-unrated button. You can switch rated and unrated only before opening a problem.
  • If you are registered as a rated participant, you'll get rated when you open a problem, even if you don't submit.

Hello, community.

Currently, your AtCoder rating changes only if you submit to the contest. This is also the case with Codeforces, so I think it's a standard.

However, this scheme clearly has a flaw; you can leave the contest without submission to keep your rating. This implies you may get underrated because of those who didn't submit. You would say things like this can happen only if you are a newcomer, and the effect will be negligible in the long term. I generally agree with it, but sometimes even reds are affected by this issue. I know some people intentionally submit CE code to make them rated. At the same time, I know some people do the "Head to F" strategy or similar things and sometimes don't make a submission.

I'm not that harsh to such behavior; rating is just an Internet point. Nonetheless, it's worth thinking about a new system. What I came up with is the following:

  • You'll have a register-as-unrated button. You can switch rated and unrated only before opening a problem.
  • If you are registered as a rated participant, you'll get rated when you open a problem, even if you don't submit.

I think these options can fulfill most of the participants' requests. For example, if you can't fully participate in a contest or just want to watch it, you can register as unrated participants and even submit during the contest (but don't get rated, of course). How do you think about this?

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By maroonrk, history, 8 months ago, In English

We will hold KEYENCE Programming Contest 2021.

The point values will be 300-400-500-700-700-1000.

We are looking forward to your participation!

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By maroonrk, history, 9 months ago, In English

We will hold AtCoder Regular Contest 111.

The point values will be 300-400-600-600-800-1000.

We are looking forward to your participation!

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