ToniB's blog

Croatian Open Competition in Informatics (COCI) 2024/2025 — Round #2
By ToniB, 6 weeks ago, In English

Hi everyone!

The second round of COCI will be held tomorrow, November 9th at 18:00 UTC. You can access the judging system here. If you are not familiar with the COCI contest format, we encourage you to read the announcement.

The round was prepared by jklepec, celin, fbabic, vito1036, itiamhr, and me.

Feel free to discuss the problems in the comment section after the contest ends.

Hope to see you tomorrow!

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6 weeks ago, # |
← Rev. 2   Vote: I like it -18 Vote: I do not like it

hello! it is possible to make sure that the cf round 985 and the 2nd round of COCI do not overlap. I like your contests and I would participate in your round, but the fact is that my life depends on the 985th round of cf (I'm serious). sorry for my poor english.

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    6 weeks ago, # ^ |
      Vote: I like it +18 Vote: I do not like it

    They do not overlap. COCI starts 25 minutes after the CF round ends.

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6 weeks ago, # |
← Rev. 2   Vote: I like it -18 Vote: I do not like it

There seems to be some discrepancy with the time. Evaluator shows the start time to be 14UTC (15 In Croatia) but here it is written to be 18 UTC.

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    6 weeks ago, # ^ |
      Vote: I like it +18 Vote: I do not like it

    The time on evaluator is set by default. It will be changed to 18:00 UTC before the contest begins.

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6 weeks ago, # |
← Rev. 2   Vote: I like it -44 Vote: I do not like it

Now I found out that the time has changed (4 hours later than the previous time).I canceled one of my important football matches for the COCI Olympiad(I didn't know times had changed).Newest Start time COCI will be late for me, so I will not participate.It is not good to change time.

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6 weeks ago, # |
← Rev. 2   Vote: I like it +10 Vote: I do not like it

the problems were so nice 🤩

but I faced something weird in the problem Blistavost

I wrote this code and it got 55 points from the third subtask but didn't get the 20 points from the first subtask (while the both of them have the same condition $$$l_i = r_i$$$ for each $$$i$$$)

here is my code, I really don't know why it worked for the third subtask and didn't work for the first one 😅

Spoiler
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    6 weeks ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    Hi, I prepared the test data for this task. It turned out that when n is big and the test cases are generated randomly, there is a high probability that you should just go from left to right(which is obviously incorrect). We apologize to the affected users for the inconvenience.

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

      so, all the 55 points in problem D are supposed to be 0 points?

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

How to solve the last problem?

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

There's no limit on $$$\sum m$$$ in problem E? Then we need to read $$$10^8$$$ edges bro

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

    The limit is lower than $$$2 \cdot 10^6$$$ Based on the $$$\sum n$$$. bro.

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      6 weeks ago, # ^ |
        Vote: I like it +13 Vote: I do not like it

      So it's guaranteed that the graph does not contain multi-edges? thanks.

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