truth's blog

Problem:992C is exact copy of a pre-existing problem.
By truth, history, 2 weeks ago, In English

It's a really unfair and sad gesture by Igor_Parfenov, author of latest Div2_992 round, Problem C was exact copy of problem : https://codeforces.me/contest/513/problem/B2

This is extremely unfair to the people who tried this problem for the first time. This also explains why so many people were able to do this problem despite it being good enough, that most of the experts in my friend-list couldn't do it.

My submission for contest problem 992C : 295640125

Exact same code submission for older version 592B2 : 295644907

Edit: I don't want to put allegations on the author of the contest, as it could be a highly improbable coincidence that he thought the exact some problem. This blog is just to highlight the fact that fairness of the contest was compromised.

people downvoting this blog cuz they got a good rank and now want the contest to not be unrated i can understand that some of you might have actually solved the problem during the contest. I am not fighting for the contest to be unrated, the sole purpose of this blog is to make sure such things do not happen again.

by downvoting this blog you do the work of suppressing the issue and if you do so how do you differentiate yourself from the people who try to compromise the fairness of the contest by any possible means.

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2 weeks ago, # |
  Vote: I like it -10 Vote: I do not like it

this is crazy..

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2 weeks ago, # |
← Rev. 2   Vote: I like it -37 Vote: I do not like it

oh yeah. so many people copy pasted the code. so many newbies and pupils solved it with the exact same elegant precise code. This contest should be unrated.

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2 weeks ago, # |
  Vote: I like it -20 Vote: I do not like it

I'm also really annoyed that this problem was a duplicate, especially considering I solved it in contest and was then accused of cheating (because my variable names were too descriptive... which I do for all my submissions). With that being said, I'd hold off on blaming the problem setter, since I doubt the problem setter knew of the fact that it was duplicated beforehand. Not to mention, this has happened before, and while unfortunate, I doubt it was from malice.

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2 weeks ago, # |
← Rev. 3   Vote: I like it -64 Vote: I do not like it

who are the clowns downvoting this? its just unfair to make this contest rated.

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2 weeks ago, # |
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What makes it unfair? Part of the skill of competitive programming is googling to figure out how to approach a problem.

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    2 weeks ago, # ^ |
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    google and get the line to line code and editorial for the problem?

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2 weeks ago, # |
← Rev. 2   Vote: I like it -29 Vote: I do not like it

people downvoting this blog cuz they got a good rank and now want the contest to not be unrated i can understand that some of you might have actually solved the problem during the contest. I am not fighting for the contest to be unrated, the sole purpose of this blog is to make sure such things do not happen again.

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

i saw this problem for the first time but it was easy for me because i just calculated sorted sequences of all good permutations for all n<9 in python console and figured out that cardinality of set of good permutations of length n is 2^{n-1} and then figured out that we can code good permutation using an element of cartesian power n-1 of set {0,1} because we just need to push number i to left or right and position of n is determined because all other positions are already determined and thats all

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2 weeks ago, # |
  Vote: I like it +25 Vote: I do not like it

How is it unfair? Everyone doing the contest had the same resources and access to the problem? Its not like it was hidden away in some Chinese OJ. If you for some reason know this specific problem from 2015 you probably deserve to solve it at that point.

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    2 weeks ago, # ^ |
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    i dont know mate maybe because people who give the contest honestly dont try to search the question on google or gpt.

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    2 weeks ago, # ^ |
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    100% percent disagree, the point of CP is to improve your problem solving abilities on problems you've never seen before, not realizing you've solved the problem before (or somehow finding it, though I'd presume that would be difficult) and just implementing the same thing.

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    2 weeks ago, # ^ |
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    People who had solved this problem previously during their practice got it easily, in fact they had to just submit their previous solutions. What else can explain the massive submission on this one, even grays and greens got this while many cyans and experts couldnt. it definitely affected the fairness of the contest.

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      2 weeks ago, # ^ |
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      There's 2651/3282 AC's on the problem from 2015. Realistically I don't think that impacts the standings that much, i.e. there is a very small number of people who weren't "supposed" to solve the problem. Just my opinion though.

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        2 weeks ago, # ^ |
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        false. Only 1300 solved it that too including div1 people. So Maybe 900 under 1900 rated solved it. So you are wrong. 2651 is the unofficial number.

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          2 weeks ago, # ^ |
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          What if, perhaps, the problem was solvable by people under 1900 rated? Its div2C after all?

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            2 weeks ago, # ^ |
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            True, it is not that hard either — one brute-force to generate all the max-value permutations and the pattern practically screams at you

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    2 weeks ago, # ^ |
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    Its unfair because it's the exact same problem and many people just copy pasted the code.. how is that fair to you I don't get this

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2 weeks ago, # |
  Vote: I like it +4 Vote: I do not like it

One the authors already apologized (editorial / announcement comments, don't remember where), and I really don't think that it should become unrated — that would be very unfair to those who solved on their own and got positive delta :p

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2 weeks ago, # |
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Auto comment: topic has been updated by ManasXD (previous revision, new revision, compare).

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2 weeks ago, # |
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Chill bro.

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2 weeks ago, # |
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As a problem writer, I can tell you from experience that its very easy to think of ideas which are already existing problems — it is not "highly improbable coincidence". The coordinator posted in https://codeforces.me/blog/entry/137074#comment-1225994 that nobody in the creation team knew of the problem before. I don't know if the contest should be unrated in this specific case, but in the past problems that have appeared before is not grounds of unrating the contest unless it is clear the author copied the problem intentionally.

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