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Copied problem in COOK89

Regards,

The third problem of December Cook Off "Minimum Subarray" is same as a problem on uva online judge which can be referred here. Also, the solution for this problem is mentioned in the comments of this CF post comments. Solution link. I ran it after the contest and here's the same solution verdict.

Hope this won't be the case in future.

PS: I waited for the contest end to post this, for obvious reasons.

asked 25 Dec '17, 00:52

taran_1407's gravatar image

5★taran_1407
3.4k1236
accept rate: 24%

edited 25 Dec '17, 01:35

I also once reported a copied question of November Long Challenge, but no action was taken for that. https://discuss.codechef.com/questions/116901/question-copied-of-november-long-challenge-chefhpal

(25 Dec '17, 01:00) vatsalsura2★

@meooow has reported this to @admin , and they are following the case. Thank you.

(PS: ty for solution. Had trouble understanding editorial- will look over those :p )

(25 Dec '17, 01:03) vijju123 ♦5★

I just hope this is not the case this time. @vatsalsura

This copying could never ever be acceptable.

PS: The solution is easy, though a bit tricky. No problem @vijju123.

(25 Dec '17, 01:06) taran_14075★

@taran_1407 why didn't you take part in the contest?

(25 Dec '17, 01:08) vatsalsura2★
1

@taran_1407 : Janta jawab chahti hai. Lol popular guy :p

(25 Dec '17, 01:11) vijju123 ♦5★
1

I was away from my laptop :D.

I am gonna solve this problem set soon. (Won't be posting editorials as @likecs editorials are usually very clear and always on time).

(25 Dec '17, 01:12) taran_14075★

So is it gonna be an unrated contest??@vijju123

(25 Dec '17, 01:19) vivek_19982996★

Thanks for your mock appreciation @vijju123

PS: I'm not "Popular guy". :P

(25 Dec '17, 01:19) taran_14075★

Cannot comment on contest being rated or unrated right now. If you'd have mailed this during contest, then immediate action was assured. Perhaps the contest would have been declared unrated depending on the time. As of now, I cannot say/predict anything before @admin gives her verdict.

Mock Appreciation?No! I meant it.

On one hand theres a poor,cute, innocent sick guy whose been at forums for eons and eons and no1 gives a fuck about him. On other hand there are an indefinite number of people keeping track on what contests you give, what problems you solve &etc. Whose the popular guy then? :p

(25 Dec '17, 01:26) vijju123 ♦5★

I mailed about the problem during the contest, but mentioned link of only geeksforgeeks article.

Hopefully this contest is unrated.

PS: Very cute and innocent guy forgot moderator word. And please!!, only a few people must be seeing my submissions (I'm grateful)

(25 Dec '17, 01:31) taran_14075★
showing 5 of 10 show all

16

OK, it seems I'm in minority regarding opinion on this one :) And I'm probably going to be rather harsh here.

Come on, looking at this problem it is kinda obvious that it has been used before (and more than once).

I wouldn't call it "copied" problem - with this kind of wording it sounds to me like setter is being accused with taking a problem from other source instead of preparing it by himself. I don't think it is the case here :)

It is definitely not a good idea to give such task, and it is a fault by setter/tester to not check it, or at least a very questionable decision to use the problem if they knew that "smallest subarray with sum greater than a given value" Google query will give you enormous number of results. People say N^2 was passing - OK, that's probably another fault by tester.

Yet overall mood of comments is really weird to me. It is both funny and sad at the same time. OK, maybe I don't get that "make it unrated" part because I don't care about rating; but assuming one would care about rating, I'm trying to imagine a situation when somebody says "let's make a CF round unrated because this problem is similar to following problem from past contest" after the round... This kind of decisions would be a great way to make CF unpopular :)

Cheating? I even had to re-check code of conduct at CodeChef to be sure that it doesn't contain yet another weird trashy rule. OK, my bad - indeed, they do have one for it. Fine, you can call these guys cheaters because they didn't add a comment clarifying that the original code wasn't authored by them. Because that's exactly what's required here for third party code. Yet another weird rule which is different from what you are used to at any other competitive programming platform, but I don't even want to waste my time on criticizing it more :)

Going back to these "copying problem" accusations - I'm not going to say that I know for sure that it didn't happen here... But here is how it looks right now: I see a lot of comments saying the same, half of them are written by newbies, and they accuse strong contestants of ICPC WF level who are also experienced setters in stealing a problem. Not "not checking if a problem is well known", but "copying a problem". And just to make it more funny, this "copying" occurred on filler task. Yep, it wasn't that typical "we got all the easy problems for a set, and now we need some nice idea for hard problem, let's look for it", but instead two yellow/red guys decided to steal a filler problem which has to be added to the set because it must contain 5 problems and because contestants of all levels participate there. Sure, that's exactly how contests are being prepared.

On a side note, talking about the contest itself - I'd say that it wasn't the best contest at Codechef ever (and this particular issue adds it another negative score), but it was generally OK, problems were nice and clear, and I wouldn't like to get this setter lost for CodeChef simply because somebody wasn't happy with the fact that filler task has been used before.

link

answered 25 Dec '17, 02:54

lebron's gravatar image

7★lebron
2.8k316
accept rate: 26%

edited 25 Dec '17, 14:59

@lebron chutiya hai?

(25 Dec '17, 03:09) coderbaba1★
3

First thing, @coderbaba I didn't like ur reply at all.

Second, i don't care about rating. (Coindidently i didn't even participated in this one, but that not the only reason).

Third, i agree with you @lebron on the point, that some problems need to be filler. Agreed. But what happens that when that particular filler problem is the problem that usually decide ranklist for middle level.

Fourth, i believe there's no harm in using past problem, as long as the setter ensure (reasonably) that there's no public solution for this problem. I found these link within 2 min on google.

(25 Dec '17, 04:31) taran_14075★

Fifth, i too liked this problem set (though didn't participate due to unavoidable circumstances) and appreciate problem setting team for this round, but i could never appreciate the idea of publically solution available problem. Even if the problem statement was like, requiring u to make an interesting(even if small) insight that reduces this problem to a standard one, i will appreciate it, but not a googlable problem.

Sixth, I'm actually glad that u shared your view point @lebron

(25 Dec '17, 04:40) taran_14075★

@lebron I agree with your criticism of the third-party code rule if the rule is to be taken at face value. However, I think the purpose of the rule is to determine the source of the code. In this case, since the source is already known, those who used the code should not be punished in my opinion.

(25 Dec '17, 18:36) meooow ♦6★

I agree with most of your points @lebron. Just clarifying one point-

The reason why codechef asks for a third party link is because, when multiple people copy from same source, then plagiarism detector flags those solutions. During manual re-checking, it makes things convenient if they include the link. Plus, they get another site to keep an eye on, to make sure no future problem is matching with some already known one.

The contest will be made unrated only if its unfair to majority of people, which I dont think is the case here.

(25 Dec '17, 18:41) vijju123 ♦5★

Yep, I understand that motivation behind the rule is probably like that. It just doesn't make the rule less weird to me. I don't have any good solution for it. I know that there is nothing like that at Codeforces, and I think we don't see feed filled with "I got banned unfair"/"cheaters aren't getting banned" there, but I don't know if it is really an issue for CF or not, and in case it isn't - how did they managed to make it or why it works well for them.

(25 Dec '17, 20:06) lebron7★

Hmm that's true. I haven't seen anything like that on Codeforces either. Does Codeforces mention anywhere how they deal with plagiarism? I searched a bit but it was fruitless.

(26 Dec '17, 14:56) meooow ♦6★
showing 5 of 7 show all

I'm sorry about this issue, when it was proposed to me it sounded like a standard problem, but the fact that it included negative numbers and the solution involved using a stack and not as simple as binary search/two pointers, that fact made me feel that the problem is original.

Unfortunately, I missed googling this problem before approving it.

There's no evidence that the problem setter actually copied the problem, so we will not penalize him.

link

answered 25 Dec '17, 16:57

kingofnumbers's gravatar image

6★kingofnumbers ♦
184822
accept rate: 12%

Thank you for the reply @kingofnumbers . The decision taken is, indeed, quite fair in my opinion.. :)

(25 Dec '17, 18:31) vijju123 ♦5★

That's no problem @kingofnumbers. I didn't knew that problem testing include googling step too (silly of me).

PS:I'm glad no one is actually penalized because of me. :)

(25 Dec '17, 21:35) taran_14075★

This platform is for learning something new and practicing, why you people are just seeing it with respect of rating. Rating goes up and down,it doesn't matter much, I think we should focus on learning not to waste our precious time on discussing such issues.Instead Discuss some problem,you all are very wise,employ some wisdom.Merry Christmas:)

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answered 25 Dec '17, 21:24

free__bird's gravatar image

3★free__bird
611
accept rate: 0%

1

Merry christmas.

I don't care about rating. I just wished to bring this to notice of admins, that's all. Hope u understand.

(25 Dec '17, 21:31) taran_14075★

This shouldn't happen in a standard contest like "Cook-Off". :(

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answered 25 Dec '17, 01:18

rohit_0801's gravatar image

4★rohit_0801
2979
accept rate: 10%

(25 Dec '17, 01:37) taran_14075★

Yes, @taran_1407 it is a problem from uva online judge and some users have copied the solution from different sources, the one you mentioned here and the other one is here. Some of the copied solutions of the users are:

  1. https://www.codechef.com/viewsolution/16654875
  2. https://www.codechef.com/viewsolution/16651503
  3. https://www.codechef.com/viewsolution/16656276
  4. https://www.codechef.com/viewsolution/16656147
  5. https://www.codechef.com/viewsolution/16656212
  6. https://www.codechef.com/viewsolution/16656663
  7. https://www.codechef.com/viewsolution/16646817
  8. https://www.codechef.com/viewsolution/16654455
    I think this kind of behaviour and cheating should not be tolerated. @admin @vijju123 please look into the issue and make the contest unrated. I hope this would not happen in future.
link

answered 25 Dec '17, 01:35

nishant0208's gravatar image

4★nishant0208
204
accept rate: 0%

edited 25 Dec '17, 02:39

Thanks for finding out submissions.

I hope admin takes an action regarding this.

(25 Dec '17, 01:36) taran_14075★

Yes, @admin please take an immediate action against this.

(25 Dec '17, 01:39) nishant02084★
2

Why should an action be taken against them? If the solution was available already, then its not their fault to be greedy and copy. Its against the spirit, yes, but its not the domain where we should dive and penalise them. Get back to me on mail if theres any more clarification needed.

(25 Dec '17, 18:32) vijju123 ♦5★
1

Agree with @vijju123. This is not "cheating".

(25 Dec '17, 18:38) meooow ♦6★

I didn't knew that there were only a few submissions (cant know, without being moderator, or in problem aetting team) so assumed that there might be more submissions which gained this way, that's only why i asked for an action. I didn't knew that there were only a few submissions.

(25 Dec '17, 21:30) taran_14075★

@nishant0208 i think you forgot to add mine. ID:16656767 I did this terrible mistake and instantly mailed codechef,setter,tester and asked them to disqualify my solution. Now it doesn't mean I didn't try solving it and "cheated". I tried for good enough 2 hours, I got frustrated because it seemed so obvious but was getting WA(Happens with lot). In last 5 min I googled just to get some common approach to attempt after contest. In b/w i saw its alrdy there and in heat of moment i submitted it. There may be many like me.I don't think it's good disqualifying all.

(26 Dec '17, 22:10) givingmybest3★
showing 5 of 6 show all

@taran_1407 that gfg solution will not work for d less than 0.I tried a similar solution to that at first,but got wa.Reason:lets say indexes 0-4 is one solution,so it'll increase 0 to 1 ,so we'll check 1-4,2-4...,bt this method would never check for 1-2 in this case

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answered 25 Dec '17, 01:29

vivek_1998299's gravatar image

6★vivek_1998299
1.5k29
accept rate: 23%

edited 25 Dec '17, 01:30

I too tried the java version of given solution and got WA, but thought that only java version gives WA. I guess i should remove that link from post.

(25 Dec '17, 01:34) taran_14075★

What we went through during icpc was that less that codechef has stooped so low TO hell with codechef

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answered 25 Dec '17, 01:30

cuteaf's gravatar image

1★cuteaf
1
accept rate: 0%

I too hope future contest don't have such problems.

(25 Dec '17, 01:37) taran_14075★
1

If you have so many problems, why are you here. Honestly, you have 2 options- improve yourself, or cry in a corner forever. Sorry, but you arent going to get success with this attitude.

(25 Dec '17, 18:36) vijju123 ♦5★

@codeaf, dont mistake my tone in following comment.

Did u know about that problem solution being available?? Did u solve the problem urself?

If no then the problem was new for you and you should try to solve this on your own.

PS: I dont know what u went through ICPC, and my concern was that if next time there doesn't appear a similar case. But i wont say codechef stooped low because i know that the mistake was unintentional.

(25 Dec '17, 21:26) taran_14075★

This needs to CHANGE as soon as possible. @admin the ratings are updated too plz see they are reversed are the codechef admins so busy in ICPC that these guys didnt even have time to se problems

TO be Honest, from the time i gave icpc i have completely lost my interest in codechef which instead of promoting competitive programming which apperantly is thei sole MOTTO during regional sites qualification, stealing problems available to everyone online.

If this doesnt stop I am sure many people will lose interest in the contests held here

LOOKING FOR RATINGS REVERSAL ASAP

link

answered 25 Dec '17, 01:56

coderbaba's gravatar image

1★coderbaba
71
accept rate: 0%

5

This is what I hate about the community since past few months. I dont see any constructive criticism in your post, and it seems like crying to me. Please have enough manners/sense/decency to formalize your complaints (and their structure/tone).

(25 Dec '17, 18:33) vijju123 ♦5★

That's the thing on my mind when i make such a post - negative criticism. @vijju123 i already braced myself to ignore such comments on my post.

And @coderbaba, i don't see u being affected with the rating change. Also, about your MOTTO, can u find any proof? if u can, write an email to codechef admins. And then, you call @lebron a ch***ya, a guy with much more expreience both at coding as well as problem setting than you and me too.

I didn't reply earlier because i was intentionally ignoring your answer.

PS: Pardon for rough tone but i mean it.

(25 Dec '17, 21:16) taran_14075★

moreover, people are getting AC in O(n^2) such poor test cases is not fair for everyone...should be unrated..didn't expect from codechef

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answered 25 Dec '17, 02:49

forcoding19's gravatar image

1★forcoding19
-6
accept rate: 0%

for(i=1;i<n;i++) {b+="v[i];if(b">=d) { b=0; for(j=i;j>=e;j--) { b+=v[j]; if(b>=d) { e=j;break; } } for worst case this goes O(n^2) but got AC

(25 Dec '17, 02:53) forcoding191★
1

Just what percentage of users are affected by it? How many $O({N}^{2})$ solutions passed? You can give this feedback to the tester, that he did not do a good job in testing the problem- thats perfectly fine.

But asking for cancellation of contest/make it unrated because 10-15 solutions passed is not logical, and let me assure you, the rating change wont be more than 5 by those. Its not worth the trouble, and the contest was more than 95% fair. Not good to make it unrated due to bad 5%

(25 Dec '17, 18:35) vijju123 ♦5★
1

Agreed @vijju123

PS: codechef isnt an avatar of god. It too can make mistakes. My sole motive was to bring this issue to notice of admins, not to make contest unrated. We dont know how it works behind the scenes of problem setting much (though i would like to for long challenge, sometime).

(25 Dec '17, 21:17) taran_14075★

https://ideone.com/e8hV4M

Hey, this is my solution, I am getting a WA, using a two pointer method, similar solutions have passed, and I really have no clue where I'm going wrong. A brute checker also has been written if anyone wants to verify a case.
Thanks in advance!

link

answered 25 Dec '17, 19:54

addy007's gravatar image

2★addy007
11
accept rate: 0%

Could u plz give link to those solution..

(25 Dec '17, 21:49) vivek_19982996★
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question asked: 25 Dec '17, 00:52

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