antontrygubO_o's blog

Invitation to CodeChef May Cook-Off (Rated for All) — 1st May — My Round
By antontrygubO_o, 3 years ago, In English

We invite you to participate in CodeChef’s May Cook-Off, this Sunday, 1st May, Rated for All.

Time: 8:00 PM — 11:00 PM IST

Note that from this month, Cook-Off and Lunchtimes will be held on Sundays instead of on Saturdays.

Joining me on the problem setting panel are:

A couple of extra words about the contest:

  • All Div-1 problems have been set by me.

  • The contest is harder than usually, so the duration is changed to 3 hours instead of 2.5 hours

  • I hope everyone will enjoy the contest!

Also, announcing Scholarship for CodeChef Certification in Data Structure & Algorithms — More than 100 Indian participants in Divisions 1, 2, and 3 will win scholarships for the CodeChef Certification exam (discounted prices). Scholarship criteria can be found on the respective contest pages.

The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.

Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.

Hope to see you participating.

Good Luck!

  • Vote: I like it
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  • Vote: I do not like it

Comments Comments (22)
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3 years ago, # |
  Vote: I like it +46 Vote: I do not like it

Note that this is the new schedule:

  • First Sunday of the month: Cook-Off [Rated for all]
  • Second Weekend of the month: The first Long Challenge (Starts Friday & Ends Monday) [Rated for Divs 3 and 4]
  • Third Sunday of the month: LunchTime [Rated for all]
  • Fourth weekend of the month: The second Long Challenge (Starts Friday & Ends Monday) [Rated for Divs 3 and 4]
  • Starters will be there on all Wednesdays of the month [Typically rated for Divs 2, 3 and 4. Sometimes for 3 & 4].
  • All short contests at 8 PM IST (+5:30 GMT)
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    3 years ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    What happened to the prizes? You mentioned that there will be a blog regarding it. But still it's not posted yet.

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      3 years ago, # ^ |
        Vote: I like it -6 Vote: I do not like it

      https://blog.codechef.com/2022/04/04/updates-for-the-month-of-april-2022/

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

        Why it's discontinued? Now more advertising is done on the websites about hiring etc. You are also organizing some boot camps by taking some money as well. I thought now the prizes will be increased so as to attract more good coders. You can see a dip in the number of participants in Div1 at least.

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

        Can the goodies section be expanded till we are allowed to redeem our laddus? Currently, there is no viable option for me to spend my accrued laddus.

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

          Forget. When I tried to spend mine with available options (pen, T-shirt, backpack) — the order was cancelled after few weeks without any explanation. And now there no even these options available. CodeChef just fucked up with the last thing I loved there (reward system).

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

    I am yet to recieve laddus for some past contest: will I be able to redeem those, if it's being discontinued?

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3 years ago, # |
  Vote: I like it -14 Vote: I do not like it

Adhoc OP

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    3 years ago, # ^ |
      Vote: I like it +24 Vote: I do not like it

    Please refrain from commenting about the problems during the contest, even if it's a vague comment.

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3 years ago, # |
  Vote: I like it +12 Vote: I do not like it

Div-2 Constructive_chef

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3 years ago, # |
  Vote: I like it +22 Vote: I do not like it

Maximum value can be found in MAXMINCRCDIF by using ore's thereom+binary search.How to construct the answer though?

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3 years ago, # |
  Vote: I like it +24 Vote: I do not like it

MAXMINCRCDIF is so similar to the problem I created in the past. So I think I must solve it in the contest.

Finally, I do it :)

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

Any idea why this solution works for B?

let first array B be x1.....x1 x2.......x2 x3......x3 xn....xn

where x1,x2 xn are elements sorted by frequency

then let second array C be reverse of this. Find the first index j from back such that there exists some subarray B[j.....k] which is a permutation C[j......k]

the array C is then = B[n-1-j....n-1]+B[0.......n-1-j-1]

Check if Array C satisfies the conditions.

I was able to come up to this pattern after observing quite a few cases but im unable to prove it

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

    Bro did you solve the triple inversion problem. I am not able to understand the editorial or anyone's solution. Can you please tell me how did you solve that?

    And for this question you can just rotate the array from mid that's it just one edge case in this when there are only 2 elements and their frequency is more than 1 like 1 1 2 2 or 1 1 1 2 2 2 like wise they will fail coz when you rotate 1 1 1 2 2 2 2 2 2 1 1 1 at mid their is a subarray which is a permutation so it will fail.

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3 years ago, # |
  Vote: I like it -74 Vote: I do not like it

Can I play with the big boys in Div1 now, antontrygubO_o?

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

    I think you'd require 1 more contest in Div 2 to advance to Div 1.

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      3 years ago, # ^ |
        Vote: I like it -37 Vote: I do not like it

      For real? But I literally won, what more do they want?

      (btw solving more problems wouldn't affect rating change assuming it's Elo, because that only takes into account relative positions)

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

        Codechef max delta is capped at 275. 275 is the delta one gets on winning first contest and it is a function of no of contests and current rating. You definitely need one more contest. Eventually is converges to 120-140 (for most people).

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

          There should not be any cap for max delta, just use the formula with no limits. This can be followed, like after 6 contests you will be around your actual potential rating, similar to what Codeforces does.

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            3 years ago, # ^ |
            ← Rev. 2   Vote: I like it -14 Vote: I do not like it

            It's the otherway round.
            Atcoder has a cap on performance if the contest has an upperbound on the rated range, which in turn stagnates the delta. (ABC's performance is capped at 2400, ARC at 3200).

            At one point in time even Mike wanted to add caps on contests which have upperbound on the rated range. MikeMirzayanov did not add any conclusions there, so no one knows why it isn't present on CF. Is it because he did not have time to implement it or did he conclude no cap on the delta is good?

            So, this cap on Codechef has some merits.

            Spoiler

            At present, a new account on CodeChef needs atleast 4 contests to reach div1, with 8 contests a month, it shouldn't be a big deal. With these hidden rating even on codeforces one need 3/4 contests to reach div1. Even rng_58 did consider it as one of the options when he was thinking about adding lowerbound on AGC ratings. https://codeforces.net/blog/entry/78109

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

        I'm sorry, but for whatever reason I find your predicament insanely hilarious. :-)

        But hey, good work! You'll be in that site's Div1 soon.

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