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Why Codeforces uses separated problems for subtask to give partial score?
By McDic, history, 6 years ago, In English

Hello.

I am wondering why Codeforces uses separated problems for subtask instead of separated test cases. Polygon is already supporting to have multiple testsets to act similar as subtasks, also Checker from testlib.h supports _pc (Partially Correct), which is intended to give partial score. So I think there is no reason to make separated problems such like R542 Div1 A1. It will be better if Codeforces just give participants partial score instead. Anyone have opinion about it?

Thanks for reading this.

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6 years ago, # |
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Auto comment: topic has been updated by McDic (previous revision, new revision, compare).

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6 years ago, # |
← Rev. 3   Vote: I like it +13 Vote: I do not like it

If your program only passes the first subtask, are you deserve to receive 50 points penalty for not passing the second one if you are able to solve the second one later? Codeforces cannot tell if you attempt to solve only the first subtask or to solve both subtasks.

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    6 years ago, # ^ |
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    What if system don't count the first personal best partial scored submission as penalty?

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    6 years ago, # ^ |
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    Replying to Rev.3

    Yeah that's why I said first personal best partial scored submission. Regardless of participants is trying to push their submission to second or not, if system do not give penalties if participant's last submission got more score than all of his/her previous submissions, that would be cool.

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      6 years ago, # ^ |
      ← Rev. 3   Vote: I like it +8 Vote: I do not like it

      There will be too many cases to consider.

      Suppose that you get pretest passed in subtask 1, then get pretest passed in subtask 2, and finally both of your submissions only pass the system test for subtask 1. Should you receive a 50 points penalty for a subtask that you do not solve?

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        6 years ago, # ^ |
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        It's a bit complicated issue but I think system shouldn't give any penalties. Because the second submission will counted as zero score if those subtasks were separated by problems.

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6 years ago, # |
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In my opinion, the only reason why authors do such tasks is because they have not enough tasks for a full contest. Ofcourse, it is not bad to split one problem into two with different constraints, if they have different solutions, but if you can solve only hard version and get AC on both, then you just have less tasks on a contest. In such cases it would be better to replace easy version with another problem. However, this does not apply to educational rounds.

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    6 years ago, # ^ |
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    1. Do they really have not enough amount of tasks for a full contest? I don't think so, I think just 5 problems are enough for 2 hours. Usually contests with splitted problems has more than 5 problems, even some contests has 7 or more.

    2. I think the case for solving only hard one is very rare :)

    3. I agree with your last sentence, it does not apply to educational rounds so there are several separated problems needed for that case. But since the single problem splitted to multiple problems, that problem is more score-weighted(at least double!) than other problems.. I think it's not fair.

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