prabowo's blog

TOKI Open 2024
By prabowo, 3 weeks 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.

  • Vote: I like it
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3 weeks ago, # |
  Vote: I like it -6 Vote: I do not like it

Allowed language: C++17

:(

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    3 weeks ago, # ^ |
      Vote: I like it +23 Vote: I do not like it

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

Is it a mirror? Or the Indonesian team candidates will also participate on this website?

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

    The official participants will have their own separate contests, but they will use the exact same problemsets.

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3 weeks ago, # |
  Vote: I like it +10 Vote: I do not like it

Will there be editorials?

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    3 weeks ago, # ^ |
      Vote: I like it +26 Vote: I do not like it

    English and Indonesian editorials will be provided after contest

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

Bump! Day 1 contest window will open in 2 hours!

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3 weeks ago, # |
  Vote: I like it +11 Vote: I do not like it

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

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

    We didn't expect the problem to be solved using centroid decomposition, but someone managed to solve it that way.

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

can someone tell their own solution for problem A Buffet leftovers.

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3 weeks ago, # |
  Vote: I like it +1 Vote: I do not like it

Centroid Decomposition 2 days in a row? Wow.

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

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    3 weeks 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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      3 weeks ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      Somehow I used CD to get 99 pts without any ideas provided in the editorial about P.

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

        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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          3 weeks ago, # ^ |
            Vote: I like it +5 Vote: I do not like it

          Nearly same solution here, but it was pain implementing it — so many edge cases.

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

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    3 weeks ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    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 $$$O(1)$$$.

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