Petr's blog

A 17107 week
By Petr, history, 11 months ago, In English

https://blog.mitrichev.ch/2023/12/a-17107-week.html

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11 months ago, # |
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Out of curiosity, what does a 17107 week mean? At first I thought it had to do with some dates, but that doesn't seem to make sense....

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

    At first, I thought it had something to do with FHC winners.

    Summing up FHC Top5 CF ratings, I got:

    $$$3486 + 3644 + 3403 + 3084 + 3662 = 17279$$$

    AtCoder ratings:

    $$$3858 + 3658 + 3648 + 3045 + 3446 = 17655$$$

    And TopCoder ratings:

    $$$4051 + 3515 + 3419 + 3035 + 2987 = 17007$$$ 🗿

    For a moment I thought I solved the challenge, but I was wrong :(

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    11 months ago, # ^ |
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    Hint: posting the grid below as a comment would prove that you understood what "a 17107 week" means (but not necessarily why I called the blog post this) :)

    @.*.*****.
#*#####*#*
###*#####*
.**.******
*#########
*#*####*##
**.******.
#########*
######*##.
**.*.*****
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      11 months ago, # ^ |
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      Lol, alr :) Thanks!

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      11 months ago, # ^ |
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      Does it mean your solution for A2 worked for all K from 1 to 17107?

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        11 months ago, # ^ |
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        Almost — it worked from 0 to 17106 :) 17107 is the first value that required adding yet another building block of k->3k-2 (this is how I produced the grid above).

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          11 months ago, # ^ |
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          Yeah, my bad to assume that the greatest value of K supported is odd :)

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11 months ago, # |
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Wild guess: in the post-contest stream SecondThread referenced Petr's blog and said something like "I wonder what would he call this week" and "I'm sure he will post it soon enough and we will find out", which is a bit rich since Petr's blog output in recent years is not great. So I think this blog is made in response (this part is not a wild guess) and maybe the name is a reference to SecondThread somehow? Like maybe Petr has run some code that created two threads, and printed the id of the second thread (this part is a wild guess)?

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    11 months ago, # ^ |
    ← Rev. 2   Vote: I like it +53 Vote: I do not like it

    The fact of writing the post was indeed in response to SecondThread's mention, but since he suggested naming the post "a sequential week" or something similar to refer to the fact that I was solving the problems from left to right, and I explain in the post that the decision to start with A was not due to the fact that it was the first problem, but due to the fact that this plan promised a better penalty, the name did not fit and I had to create a new one :)

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11 months ago, # |
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Petr mentioned MEX-related problem E in his blog. Early in October 2023 when the problem has been already planned for the Finals, I've checked his blog and the latest post was "A MEX week", so I had to check all the MEX-related problems mentioned in the post to make sure those are different.

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    11 months ago, # ^ |
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    Problem E from Petr's blog in MEX week served as inspiration for me to set problem B in round 3 of MHC (not finals). Some people caught up to this fact — comment.

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      11 months ago, # ^ |
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      inspiration

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        11 months ago, # ^ |
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        Are you claiming the problem is a direct copy and paste of the CodeTon round, a round you participated in, and you happen to fail it during MHC? Not all versions of solutions solve MHCs one, including the one explained in editorial from CodeTON round

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          11 months ago, # ^ |
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          It depends on your criteria for originality. If your criteria is my having failed your problem and "the modified problem doesn't admit the solution from the official editorial, only from the comment section", then your problem is original. However, my opinion is that on a scale from original to stolen, your problem is artificially crafted so that some publicly described solution to a recent similar problem also fits for yours, which is closer to "stolen" than to "original".

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            11 months ago, # ^ |
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            Maybe we put it a third time in next MHC to see if you can get it

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