While solving random problems on DMOJ I found this problem: Problem, Contest the problem appeared in. I only read the statement and decided it was not for me, so I moved on. Today after the round I remembered this problem because it seemed similar to 1726F - Late For Work (submissions are not allowed). Not only are the problems exactly the same, they even share the same sample and the explanation of the sample is also the same: 
Together with the fact that little_angel has solved this problem on DMOJ:
I am convinced that the authors of Codeforces Round 819 (Div. 1 + Div. 2) and Grimoire of Code Annual Contest 2022 have purposefully copied the problem and didn't even try to hide it. I don't think the contest should be unrated, because the impact was not that big. But I still believe that this is unacceptable for Codeforces contests. You are supposed to create original problems.
zxyoi 2.0
Yeah, this is really blatant. They changed the statement to remove the characters appearing in the original contest but didn't even bother to change the samples >_>
The author of the problem was indeed little_angel:
certified bruh moment
Auto comment: topic has been updated by jeroenodb (previous revision, new revision, compare).
Wow. I really did not expect TWO copied problems in ten rounds.
So is this round going to be unrated? Even though the impact was smaller than Round #810, it is (probably) still a deliberately copied problem so I think it makes sense to make this round unrated.
I guess it won't. Problem F kind of did its job during the round, there is only a problem what to do now.
Thanks, KAN. I just want to let Radewoosh know that something that worked fine during the contest shouldn't be the reason that a contest remains rated an argument you presented that day.
Well, I’d be fine with leaving the round rated or making it unrated, but I guess it’s also a case of dealing with the author. Codeforces wants to be friendly and nice and it’s good. If someone tried hard and failed in some way, then the situation is treated differently than if he did something bad.
**TWO copied problems in four rounds.
Div 2/3/4/5/6/7/8/9/10 shouldn't be counted.
This happened two weeks ago too :)
Non-Div1 rounds are also rounds.
The additional funny moment is that my WA solution that was accepted during the contest gets WA in DMOJ! So, it was not just copied, it was made even worse!
Thinking from the POV of someone that copied a problem: why would you work hard to create good tests if you didn't work hard to create the problem?
But actually he means the tests are even weaker than the original ones. You can see that he got AC during the contest but after then he got uphacked.
UPD: sorry I didn't see this comment carefully and misunderstood him:(
The tests, in particular, were not made by him. The tests for all problems were the responsibility of me and anubhavdhar, so it is our fault. He only provided the statement/samples/sample explanations for the problem.
Wow. If you’re a problemsetter it sometimes happens that your problem was independently invented by someone else, nothing weird here, we simply already exceeded square root of the number of possible problems and birthday paradox is happening. Of course, stealing it is something way different. It makes me wonder: how can we protect ourselves from something like this?
In this example fortunately the samples and the explanation are copied — extremely dumb move if you want to hide a crime, this guy wouldn’t rob a bank. But what if next time some other guy will be smarter and will hide it better?
Well, fear no more. If he’d be smarter, he would not copy the problem. So I guess there is really no problem and everything will simply be fine.
Can you provide details regarding number of possible problems.
7
why cannot we create a project where we can classify a task mathematically, like using some type to define a unique tag ,
like rearrange a permutation -> tag A , also use solution/editorial of task to attach more tags, now we can use Alphacode like AI , to check if similar task exist or maybe some similarity index, so we can at least get list of 10-15 similar task at most if they exist, and just compare manually. I know there might be some task which can be translated to some dual version of it, but it would still be very helpful. Currently we just have to rely on contestant memory.
Secondary advantages of this database would be : it would very helpful for the training of candidates, so they don't have to classify things themselves.
I think why this should work is because whenever I need to search something , I just search things on stackexchange sites or research papers, by using academic keywords.
You know that codeforces already has tags?
Yes but those are very abstract, here i meant more detailed.
Shamelessly copying problems from the net and then praising a bunch of guys for "proposing original problems" , "testing and providing feedback" blah blah in the contest announcement blog lol. Is this what the coding club of IIT KGP has come to?
Just leave problem F, what do you have to say about other problems? Even tourist couldn't solve problem H and you are saying Is this what the coding club of IIT KGP has come to?
Tourist couldn't solve HAnd how does that in any way make copying problems legal?what do you have to say about other problemsEven if I were to say the other problems were good, what difference does that make? Becoz of 1 copied problem, the entire contest got unrated and wasted 2-3hrs of everybody's time..you are saying Is this what the coding club of IIT KGP has come to?Well, as per the contest announcement blog, this round was brought to us in association with the coding club of KGP. So did the members of the coding club not know this problem was copied from the net? Or even after knowing, they purposefully went ahead with the contest? Either way it shows their mismanagement.The contest being unrated does not necessarily mean that the participants wasted the time. After all, they were able to solve new problems and improve their skill in CP.
And how does that in any way make copying problems legal?When did I say that copying problems is legal? I just meant that authors spent a lot of time in preparing other problems, which were ORIGINAL! Also, its testing and other stuffs take considerable amount of time.Becoz of 1 copied problem, the entire contest got unrated and wasted 2-3hrs of everybody's time..As pointed by SSRS_, contest is not just about gaining ratings!stop trying to defend your friends, and your shitty university.
Just check out latest post in this. I don't want to say anything else...
It's ok if you didn't score well in JEE Advanced :P
A single problem is not the basis of the whole contest. Even the quality of questions from A to H had a very good level and logistics. Defaming it is completely inappropriate way. Even DMOJ is not even a very popular platform that people are aware of that problem.
Bro, the contest had 8 freakin problems! Just make a round with 7 not stolen problems, it would still be enough for everyone to enjoy the round. And authors would not get such flame.
bruh the problems from A — H were excellent, except for the problem F, and as @coder_K20 pointed out that DMOJ is actually not a very well known platform, and bruh settin up an entire contest takes a hell lot of time and effort (you woulda known if someone from your college had actually set a contest lmao) and not many people were able to solve F even after it was present already.
The replies of the people above are funny.. Y'all seem to insinuate that just becoz DMOJ is not a very popular website, it's okay to copy problems from there...And even if I were to say that the other problems were good what difference does that make? The author was caught copying problems from the net and the entire contest has now become unrated which has angered a lot of people.
bruh settin up an entire contest takes a hell lot of time and effortAnd that gives the author the license to copy problems?I solved till problem C, and all three were unique and were good problems(review of my friends too). You cannot judge the whole club based on one imposter, and that too he has accepted his mistake, and first of all, have the guts to comment from your main ID, you a little piece of...
You seem to be more concerned about bashing me for being angry with the contest author for copying problems from the net, instead of criticizing the author for doing such a deed. Good thing the CF community is gonna blacklist that author so that no one ever tries to do this again in future.
You are a donkey and a coward who is commenting from a fake account. The author has accepted it's cheating that too from his main account. Don't comment if you don't dare to say it from your main account. I also criticise the fact that he copied, but you moron is just behind the fact that the entire club and all the authors are responsible because of one copied problem.
I don't mean to sound rude. But why is it that whenever cheating happens Indians (sometime Chinese) are somehow related to it?
This doesn't just seem to be a standalone phenomenon. In every contest be it Kickstart, Hackercup, Codejam you'd find telegram groups— predominantly Indians— engaging in illicit practises!
Maybe this little_angle guy too thought the same? Maybe he's being doing it for too long? And he's not sorry because he copied the problem, he's sorry because he got caught.
What I'm trying to convey is Indians need to get their house in order, before someone decides to completely ban them from competing!
Is the setter a friend of yours that you are getting fired up like this? If a member of a club involves in some illicit practice shouldn't the blame fall on the entire club? You want me to believe that not a single person from the entire coding club of IIT KGP realised F was copied from the net? How am I in the wrong if I blame the coding club of KGP for this unfortunate incident...
"You want me to believe that not a single person from the entire coding club of IIT KGP realised F was copied from the net?". Yes, this is where you are wrong :)
No, I don't know him, but I have common sense and (unfortunately) you don't have it. No, it may be possible that no one knows. At last, if you copy or cheat, will you publically announce that I have cheated and achieved or done this task? No, it's unfair to blame the whole club. If you blame the person who copied the task, you are correct, and I support that it was wrong, but blaming the entire club because of him is morally wrong.
I thought it looked standard-ish and like I solved something similar before...
I log in after a year and this is the first thing I see.
Maybe I should go back to playing valorant (︶︹︶)
little_angel Why have you deleted your apology blog?
Because certain anonymous accounts doxxed him in the comments of the blog.
doxxed him? You posted his name in the announcement to the contest. He himself had this info on his profile until he got caught cheating, then he quickly deleted the information, but it's still easy to google his name on other OJs.
It wasn't limited to just his name.
What else was there? His linkedin or github profile? It doesn't qualify as doxxing if the info is present on the first page of a google search.
Alright, but consider that most people won't do a google search on him. And then you have this info being posted here, for angry people to see. Even if it is not doxxing, wouldn't you consider that harassment? In any case, I do not find it acceptable.
Again?This seems too frequent.