prabowo's blog

By prabowo, 5 months ago, In English

Hello Codeforces!

We will host TOKI Open 2024. This is one of the tests to select the Indonesian team for IOI 2024. Everyone is welcome to take part in this contest.

The contest will be held in two days:

Some key details of the contest:

  • Duration: 5 hours
  • Style: IOI
  • Allowed language: C++17
  • You can start at any time within the 22-hour window.

All contest days are hosted on TLX. Please register for an account if you do not have one. More details on the contest rules are available on the contest page.

The results will be published within one day after each contest day has ended.

We hope that you will enjoy the contest. Good luck and have fun!

UPD. The day 1 contest has ended. We have published both the scoreboard and the editorial, which can be found on the contest page. The day 2 contest window will start soon.

UPD2. All contest days have ended. Thank you for your participation, we hope you enjoyed the problems!

You can upsolve the problems here. The editorial can be found on either the contest page or the upsolve link. The combined scoreboard for both days including the official contestants will be published soon.

We thank everyone who is involved:

We hope that we can host TOKI Open again in the future!

UPD3. You can find the complete combined scoreboard of both days here.

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5 months ago, # |
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Allowed language: C++17

:(

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    5 months ago, # ^ |
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    The IOI 2024 contest environment is not published yet, and IOI 2023 was using C++17, so we try to make them as similar as possible.

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5 months ago, # |
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Is it a mirror? Or the Indonesian team candidates will also participate on this website?

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    5 months ago, # ^ |
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    The official participants will have their own separate contests, but they will use the exact same problemsets.

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5 months ago, # |
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Will there be editorials?

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    5 months ago, # ^ |
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    English and Indonesian editorials will be provided after contest

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5 months ago, # |
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Bump! Day 1 contest window will open in 2 hours!

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5 months ago, # |
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Can Copper Mine be solved using Centroid Decomposition, or I have lost in the math of the time complexity?

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    5 months ago, # ^ |
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    We didn't expect the problem to be solved using centroid decomposition, but someone managed to solve it that way.

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5 months ago, # |
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can someone tell their own solution for problem A Buffet leftovers.

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5 months ago, # |
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Centroid Decomposition 2 days in a row? Wow.

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    5 months ago, # ^ |
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    ngl the editorial for 2A that uses centroid decomposition reminds me of this

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    5 months ago, # ^ |
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    The intended solution to get accepted which uses $$$Q\leq20$$$ doesn't use centroid decomposition. However, towards the end of the contest preparation, one of our committees found a solution with $$$Q\leq16$$$ which uses centroid decomposition. In the end, we decided not to lower the constraint for $$$Q$$$ and kept it at $$$20$$$, so that solution isn't necessary.

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      5 months ago, # ^ |
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      Somehow I used CD to get 99 pts without any ideas provided in the editorial about P.

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        5 months ago, # ^ |
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        Yeah I had ideas using CD (centroid Decomposition) as well.

        ideas

        I could not implement these ideas in time, do you think they were correct> I think even if I have done some naive queries I would have got at least 80 points (assuming I get 30 points in subtask 1 and subtask 2 and 50 / 70 in subtask 3).

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          5 months ago, # ^ |
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          Nearly same solution here, but it was pain implementing it — so many edge cases.

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5 months ago, # |
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Can someone please explain the dp solution for subtask 2 of buffet?

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    5 months ago, # ^ |
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    The operations are equivalent to picking one non-decreasing sequence (corresponding to type 2 operations) and one non-increasing sequence (corresponding to type 1 operations). We save the last element in the non-increasing and non-decreasing sequence in the dp state, along with the index, for a total of $$$O(N \max(A)^2)$$$ state. The transitions can be done in $$$O(1)$$$.