luogu_official's blog

CSP-J/S 2024 Simulation Test
By luogu_official, history, 6 weeks ago, In English

CSP-J/S is the most influential informatics competition in China. This year, over 250,000 candidates participated in CSP-J/S, and more than 50,000 candidates are estimated to take part in the second round of the exam. To help contestants prepare for CSP-J/S, Luogu has organized a simulation test. Contestants are welcome to familiarize themselves with the types and difficulties of tasks or get acquainted with the algorithm competition environment in China.

In this contest, the statements in PDF, both in Chinese and in English, will be provided. One can download the PDF version in the attachment of task A. Moreover, samples will be provided in the attachment of each task.

This contest is not full-feedback. You will not receive the results during the contest, and the score of each problem is only dependent on your last submission.

We are looking forward to your participation! English statement will be provided officially. We are working on establishing an English platform, but it takes time. We plan to complete this task by the end of 2024 or early 2025.

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6 weeks ago, # |
  Vote: I like it -16 Vote: I do not like it

Thank you luogu for providing such a great contest!

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6 weeks ago, # |
  Vote: I like it +21 Vote: I do not like it

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

As a CSP-J contestant,I hope everyone can win the first prize!

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6 weeks ago, # |
← Rev. 3   Vote: I like it -39 Vote: I do not like it

Welcome to join this useful contest for CSP!

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    6 weeks ago, # ^ |
      Vote: I like it -32 Vote: I do not like it

    Your English is so 6

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

      What do you want to express by writing this comment?

      Stop commenting useless words on Codeforces....

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        6 weeks ago, # ^ |
          Vote: I like it -17 Vote: I do not like it

        That's right.

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        6 weeks ago, # ^ |
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        I think they are just pupils around 11 years old and are weak in English I guess.

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

As a writer, welcome to participate!

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6 weeks ago, # |
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As a tester, I think the problems are interesting!

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

why i can't get in to luogu.com.cn now

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    6 weeks ago, # ^ |
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    If you are not in Chinese Mainland, your visit will be much slower. Even inaccessible.

    Try changing the network environment.

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6 weeks ago, # |
  Vote: I like it -32 Vote: I do not like it

Can I qp here？

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6 weeks ago, # |
  Vote: I like it +31 Vote: I do not like it

Yeah but nearly 80% comments come from Chinese.

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

    But are the downvotes voted by Chinese? upd:I think it's actually not so necessary to downvote comments that isn't so readable, especially when you are not participating in the contest mentioned in this post and is just downvoting for their bad command of English.

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

Stop using Chingish to comment!

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6 weeks ago, # |
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GL && HF!

em,I got 100+100+64+0=264 points during the contest,but I wonder how to solve T4?

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6 weeks ago, # |
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Hope to provide large examples. Then hope everyone good luck!

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6 weeks ago, # |
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It seems that many testers come here to show their English ability,ha

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    6 weeks ago, # ^ |
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    Yours doesn't seem good either. In my view, the word "testers" should be "participants".

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      6 weeks ago, # ^ |
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      Thank you for correcting my mistakes.I'll tend to pratice ans pursue the improvement of Eng

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6 weeks ago, # |
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GL&&HF in SCP-S

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6 weeks ago, # |
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I think SCP-S is harder than CSP-S2023.

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6 weeks ago, # |
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How to solve SCPS 2024 T1?

I do not have any idea.

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6 weeks ago, # |
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What's the simplest solution of CSP-S T3? I used random heuristic for general cases and got 100pts.
My heuristic is, we can calculate the optimal $$$k$$$ easily and matching random $$$k-1$$$ (current mode)-(current second mode) pairs, after that pray so that the remaining characters don't form a palindrome.

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    6 weeks ago, # ^ |
    ← Rev. 2   Vote: I like it +38 Vote: I do not like it

    This is one of the intended solutions. My solution requires some case work and it is deterministic.

    Disclaimer: The contest is SCP-S, but not CSP-S.

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      6 weeks ago, # ^ |
      ← Rev. 2   Vote: I like it +11 Vote: I do not like it

      Sorry for my curiosity, do you have some intended solutions, with some analysis of successful rate?

      PS: Where is the editorial?

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        6 weeks ago, # ^ |
          Vote: I like it +14 Vote: I do not like it

        Unlike atcoder, in luogu the editorial writen by users will be published after they are checked by the administrators and it usually takes 3~4 days.

        The official editorial will be published 3 days later, too. If you want to read it now, you need to pay to luogu, or enter the luogu QQ group, where luogu users discuss solution.

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    6 weeks ago, # ^ |
      Vote: I like it +22 Vote: I do not like it

    My solution:

    • If there is an absolute mode(>=n/2 occurrence) in the sequence, the upper bound of the answer is n-occ(absolute mode) since that each subsequence need two different numbers.
    • It's trivial for bound=0, and the only impossible case for bound=1 is the string itself is a palindrome(like aabaa).
    • For bound>1, we select an non-mode element arbitrarily and use other non-mode element to make the last string as "unbalanced" as possible: each one takes an element on the side of less occurrences.
    • Otherwise, answer is n/2. Throw an element away with the maximum occurrence if n is odd, then pair the others, and let the element thrown away join a subsequence without itself.
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6 weeks ago, # |
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too hard.

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6 weeks ago, # |
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Are there going to be editorials for the contest?

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6 weeks ago, # |
  Vote: I like it -40 Vote: I do not like it

I think SCP-S is not very well, is it?

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4 weeks ago, # |
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The csp-j is so suck T1,T2,T3 are easy,but T4 is terrible!

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