Hi.
Of course, there was an unpleasant incident with the problem today. In fact, the problem almost coincided with another problem in the old round, which was hosted 5 years ago.
You, of course, are shocked. You, of course, think that the round should be unrated.
You are wrong. Here's why. We need to clearly distinguish between two scenarios with coincided problems in our rounds.
First. The writer has knowingly plagiarized. This is an outrageous scenario. Such behavior knows no excuse and it is a conscious detriment to our community. Shame on the writer!
Second. The problem was matched unintentionally. The writer was unaware of some old problem. This happens. The coordinator had not seen this old problem before or had forgotten it. We are all human. The round was tested, but the testers did not indicate such a coincidence. Too bad, it happens. Who can we blame for this situation? The writer? Most likely, the writer did a lot of work to prepare the round. What can we blame else? The coordinator? Do you really think that a coordinator should remember all 8500 problems from the archive (and, by this logic, 10,000 more from various other sources)? Show me such a person! Oh, you haven't heard of them... Maybe the testers are to blame? Or me personally?
No, all these people have put a lot of effort into preparation. You may have partially lost the buzz from solving the 2-hour round. The authors and coordinator put weeks of work into it!
Have you noticed that every Codeforces round has been tested by a much larger number of testers in recent years? Thanks to them! We put a lot of effort into it. But failures like this happen.
I insist that in such cases, no recriminations are acceptable on those who prepared the round for you.
I’m living in the world of programming competitions for more than 20 years. And I have seen the coincidence of problems, not only on the Internet rounds, but in more serious competitions. It happens. There is only one way to avoid it — do not hold competitions. Stop writing new problems.
In any other case, it will sometimes happen. If it did not happen today, it will happen tomorrow. All we can do is make some effort to prevent it.
We come up with and solve problems that revolve around a narrow set of topics. We are inspired by similar models, learning from similar educational tasks. Of course, sometimes people think alike. And this happens everywhere, whether in science, art, or any other field of knowledge.
But someone was wrong in this situation, wasn't he? I'll answer who. Those who wrote public comments of "aah! the problem is the same!" Those who rushed to write a post about it. Are you out of your mind? There were orange participants among you, and you still have no sense of the ethics of the competition? Why don't you read the terms of participation you confirmed before a round?
If a participant remembers a wide range of tasks and knows how to put them into practice, that's not a bad skill. Let a small fraction of participants be rewarded for this if such a mishap as a problem coincidence occurs. No one in their right mind would shout "let's cancel the results of the ICPC finals because there was a problem coincide". Although the price of victory and reward there is several orders of magnitude higher than another round on Codeforces.
I am strongly against the creation of such a precedent. You can't make a round unrated if unintentionally some problem coincided with some other old problem. It's a road that leads into a swamp. And we may not get out of it.
Why don't you read the terms of participation you confirmed before a round?
Most people don't read
The registration confirms that you:
* have read the contest rules
* will not violate the rules
* will not communicate with other participants, use another person's code for solutions/generators, share ideas of solutions and hacks
* will not attempt to deliberately destabilize the testing process and try to hack the contest system in any form
* will not use multiple accounts and will take part in the contest using your personal and the single account.
Yes.Most people don't read it,even don't read any important post.But I think It's necessary for user to know about it.How to deal with this problem?
in fact, we won't get punished if we try to copy the solutions from the old problem. cheaters will get higher marks and higher ratings. that's why it should be unrated.
even if cheater's got more rating with this round they can't sustain that position of over the period of time everything will be fine so just chill.
cheaters include those who take contest in group, and sharing information and ideas.
totally true , and with blog criterion all writers they can reuse their problem in more than one contest ,so i think it should be unrated
THE TERMS ARE USELESS AT ALL IF THE CHEATERS ARE NOT PUNISHED
Of course I know you are right , but what's police used for if a law works.
This is codeforces:
MikeMirzayanov
I have liked this comment. I have nothing to do with the author. Due to my shallow knowledge, I can't judge whether the comment is bad. If so, please call me and explain the situation. After verification, I will cancel it within 15 working days and reflect deeply.
If this game is rated, it means that CF is acquiescing to large-scale cheating and low-quality questions. This will set a bad precedent for the future development of CF.
If there are many lazy questioners who directly use previous questions in the future, how should we deal with it? See them as careless?
Actually,I know this problem as same as 765F.I search on the internet,and then I find the answer. I didn't copy it because two reasons.
(1) I'm afraid I will skip this round.
(2) People who copy it have not got any harvest.
Only f**king one competition cannot shows someone's power.If you strong all the time,you wont care about this because you are strong enough to make your rating higher next time.
I hope everyone to make your rating higher next time.
In my opinion,if our goal is only to rank up, it will always be unfair for somebody whatever the result is. But we’re joining this contest to train our skills, thus coinciding problems will cause nothing: we can still learn what we want from this contest.
We can make sure we will obey the rules,but we cannot make sure others will.Anyhow,it will lead to an unfair contest.
Irrelevant. You don't have to copypaste someone else's solution to an old problem as long as you can read the editorial or even a discussion about solutions. Therefore "just don't break the rules" doesn't answer the question here.
Maybe as Moscow Olympiad for Young Students it's okay, but I think it should be unrted as an online contest.
You did not read the post, did you?
The post doesn't answer the question of why this round should not be unrated.
"But the problemsetters tried so hard" is barely an argument. Yes, they tried hard, nobody denies their work. But why would their work be invalidated as soon as their contest gets unrated is beyond me. Contest being rated only matters in first 2-3 hours, and the rest of the problem's lifespan will be spent as a problem to upsolve, where it doesn't matter if the contest was rated or not.
Mike wrote a big "nothing" burger of a post, which was basically "well coincidences aren't bad, so the round is not unrated". No shit sherlock, nobody blames coincidences, but 1) People got an unfair advantage due to comments about 765F, and then it spread everywhere, because people thought it will be unrated anyway and 2) people who didn't know about 765F got severely fucked over, and therefore they had a unsatisfying time solving the contest.
I am not a problemsetter, but if I was, my main priority would be "Most people should have a pleasant experience with my contest/my problems". And, personally(absolutely doesn't mean authors of 852 should do), I would ask for round being unrated myself, because that would satisfy most people, and make it so people who "played fair" didn't regret about this decision.
Mike only considered the feelings of the problem setters but he didn't care for the feelings of the participants.
Talk on your behalf not all participants
in fact I didn't take part in this round at all. I only think this is unfair for those who didn't know F coincided with CF765F.
Why should Mike consider the feeling of the shameless cheaters?!
I did not refer to the shameless cheaters. I only think this is unfair for those who didn't know F coincided with CF765F.
1) where do you draw the line?
if the solutions are exactly the same? if the thinking processes are exactly the same? if the general data structures used are exactly the same?
Why did you decide to draw the line there? Why should others not draw the line differently? Mike rightly said its a bad precedent
2) Experience gives the ability to recognize what data structures/algorithms/general ideas will likely be used to solve the problem, the only unfortunate part in today's problem is it gives the whole solution instead. Why exactly is the first one alright, but the second one such a big problem.
By having a look at the recent codeforces rounds that got unrated, it was due to the exact overlap with known problems from the previous contest. Meanwhile, if you look at almost all contests, the problems may use the part from other known problems, but the overall idea is still original. But these contests are still rated. So, the threshold is still pretty clear for whether the contest will be rated or not. The today's contest shares the exact problem from previous contest so ideally it should get unrated as the trend suggests. I have not given the round.
You're wrong.
Recent rounds that were unrated due to things like this were unrated due to plagiarism. Even the tests were the same, as the "author" didn't even bother to change the tests.
I think in this case the
round getting unratedhave no correlation withauthor's hardwork. The round should be unrated as it will be unfair to good number of participants. At the same time, author's hard work will be respected as the problem will be the part of archive. Yes, you are right that in previous round, the authors deliberately attempted to copy the problem which may not be the case in today's round. But the decision to make the round unrated was taken by keeping in mind the fact that it was unfair to most participants. Have those copied problem were not identified by anyone. Do you still think the round had gotten unrated? Also, I guess in previous such rounds, the concerned authors were punished by not allowing to make problems again (I may not be right here).I agree with your first sentence, as in my opinion authors should be free to use past problems as long as they give credit to their "inspiration" and the original problems weren't too recent.
In fact, such things have already happened when people used papers as source for round problems. I see no harm in that.
I do see harm in contestants jumping into the announcement comment section and saying which problem is the similar to it. I think such people should be banned.
And to be clear, people that went to the announcement comment section and copied the solution did nothing bad and shouldn't be banned.
I think that either the round or just the problem should be unrated if this happened.
the problem is this task is so classic that many people had solved it before, and there even has been a couple of problems based on it.
I agree. Now that I've looked at the problem I also recognize it as a problem that I've revisited around 5 times in these last few years. It's an imporatant problem for me because it taught me that log might be removed in mo's algorithm by using linked lists sometimes.
As a tester I would've instantly recognized the problem. I still think such things shouldn't be a problem for div2 as it's been 5 years or so since the problem appeared and people in div2 most likely don't know the original problem unless people spread that information during the contest.
Could you describe how you would go about removing the log factor in mo's algorithm for that problem? I don't really see how you could do that with linked lists (probably because I never really used them). Thanks.
Seriously, did you read the blog?
nobody wants an unfair round. btw which problem was copied?
Yeah, no one should be blamed, but the round is unfair finally; no one is responsible, but it happened. So what, we just sit?
No matter it is unintentionally or not, the result is the same, isn't it?
your English is so Chinglish，a little bit funny.like "we just sit"
So? It's enough to talk.
Totally opposite to you, I think "just sit" sounds like a phrase used by a native speaker.
You need to play Genshin Impact.
Then everything is reasonable.
woc op
your English is so good （doge
Enough, leave it I can't believe such things of no importance also lead to criticism of Genshin Impact. Firstly, Genshin has never irritated you; secondly, it has never done anything intolerable, so what is wrong with you that you keep discrediting Genshin mindlessly? Mihoyo is dedicated to cultural exportation and Chinese propagation, however maniacs like you know nothing but tapping keyboards online, calumniating our great company of conscience. The bright future of Chinese indigenous electronic games will definitely be devastated by people like you.
Why there is Genshin Impact everywhere.
Because of the original problem CF765F(?)
upd: not.
You are right, but Genshin Impact is a new open world adventure game independently developed by miHoYo. The game takes place in a fantasy world called "Tivat", where the person selected by God will be granted the "Eye of God" to guide the power of elements. You will play a mysterious role called "Traveler". You will encounter companions with different personalities and unique abilities in your free travel, defeat powerful enemies with them, and find lost relatives — at the same time, gradually discover the truth of "Genshin Impact". Because of your poor quality, I can earn 150 yuan every day when I play Genshin Impact every day. My monthly income is about 5000 yuan, that is, the income level of 5000 dollars in real life every month, which translates to at least 30000 yuan. Although I am only 14 years old, I have exceeded the level of most people in China (including you). This is the proud capital Genshin Impact has given me. It is no exaggeration to say that "Genshin Impact" is the most ambitious work of miHo Yo so far. Even after 8700 hours of hard fighting, the game still has many undiscovered secrets, missed weapons and equipment, and never used spells and skills. Although the combat experience in the game is not much different from what we have seen in the previous series of games, all kinds of carefully designed enemies and Boss battles in the game have raised the fight to a new level. Just like the Legend of Zelda a few years ago, Genshin Impact is an excellent work that can promote the development of similar games.
□□□□，□□《□□》□□□□□□□□□□□□□□□□□□□□□□□□。□□□□□□□□□□「□□□」□□□□□，□□□，□□□□□□□□□□「□□□」，□□□□□□。□□□□□□□□「□□□」□□□□□，□□□□□□□□□□□□□、□□□□□□□□，□□□□□□□□□，□□□□□□□——□□，□□□□「□□」□□□
such wise words have never been said before
deleted
You're right, the clothes and bag are new for you.
eh
lol, what's the deal with all these Genshin jokes?
Some stupid Genshin Impact players do disgusting things on Internet,so many people curse them,then the players curse back with stupid words.Many people think these words funny,so make them jokes.
oh, so CF765F is some sort of curse word?
No,it's just the origin problem.
Beware that Chinese memes invade Codeforces
True dude
You are right, but now I can earn 150 rough stones every day playing Genshin Impact, which is about 5,000 rough stones a month, which is the income level of 5,000 US dollars per month in real life. In conversion, it is at least 30,000 yuan, although I I am only 14 years old, but I have surpassed the level of most people in the world (including you). This is the proud capital that Genshin Impact gave me.
Yeah, as a problem author for other contests, this is one of my biggest nightmares. I try hard to make sure I'm not using a problem that has existed before, but I know I haven't seen everything. Especially when you write simple and easy to understand statements, it's really scary it might happen.
and you do not care that it could affect the rating of other participants
my brother in christ you are grey
Completely right!
Yeah. I think most rational people can understand you. Coincidences can't be avoided somehow. So I think those who use rude words to blame any of the contributor are irrational and babyish. The only who should be blamed are those who copied the code and broke the balance of the competition. If we can find a way to punish those plagiarists, then everyone can get a good result. But it's hard to figure out those participators.
The reason why so many players (including me) want to unrate this competition is that those plagiarists did break the balance of the competition and make many players suffered undue losses.(I need to say it's not an excuse for some of the weak players) We know that unrating a problem is a great setback for the authors, but the consequences we face will be heavier than not unrating the contest(not only for some rating but for the whole environment in Codeforces).
I don't think it's fair for you authors, but as it's a coincidence, like a great rain breaks the flowers in your yard, you do nothing wrong but it's finally unfair to you. We are all sad about the result, and we can only pray that this unfortunate thing will not happen again.
So why not clarify it in the contest in time?
You don't want to draw attention to the fact that there's an answer on the internet somewhere. Everyone would stop thinking and start googling, exacerbating the problem.
Well, we need the rules about unrated.
How about removing problem F from the round, instead of making it unrated. I know neither of the decisions are good for the people who invested their time in it.
But, I feel the former is better considering most of the people who solved F, were unrated participants (or could possibly have the potential to get into div1 easily).
positive solution
Removing the problem and keeping the contest rated is the worst decision IMO. As you said, some people may have invested their time in it. Maybe even chose it over some other problem to gain more points and eventually solved it from scratch. But let's just remove it. Awesome!
Those who can solve a 3100 rated problem from scratch in a div2 contest, can easily gain ratings in another div2 round imo. That's what I meant in my last line.
Also, by removing the problem I meant to remove it from the contest only, and not from the cf problem-set.
Those who can solve a 3000-rated problem from scratch in a div2 contest, can easily gain ratings in another div2 round imo.
It's still nonsense to those people. Even if there's only one. Either keep it rated as stated in the post (at least you are not taken away the problem that you fairly solved). Or make it unrated (unrated contests happen from time to time).
there are a few people who solved it without copying solution, imagine solving F after an hour long toil and then you get put back with the abc or abcd solvers
(somebody wrote what i wanted to just 2 mins before me)
It's unfair for the group of people who didn't know the problem but invested time on solving it.
Does unrating a round effect the author's feelings more than the discontent of the participants affected? Can a round, and the authors' hardwork, not be appreciated independent of the round being rated or not?
I think the then the problem setters will feel(subconsciously) that they just created a gym contest
I left the round without solving a problem thinking it will be unrated. :)
what else ?
You shouldn't enter the contest only because of rating. What is this "No rating? I will leave the contest then"? Be mature. People should enter codeforces contests because it is good preparation for the actual contests, it is fun and it helps you improve your coding skills. And the rating is just the tool to see your level.
Will the submissions that totally copied from 765F be skipped?
No, since it is allowed to copy code that exists freely on the internet before the round starts.
Perfectly said by Mike sir. Some who don't know about that question has put millions of effort to get it right for rating increment. It is unfair to make it as unrated one
But it's also unfair to those who put effort in this rating if it's rated.They have a lower rank than they should be because of cheaters.
I agree with the post. I respect everyone contributing to the conduction of contests and understand the effort that goes into the process. Despite having performed poorly today, I found the problems to be quite interesting and had fun! A negative delta will just work to remind me of the shortcomings I had :)
You will climb back. I can tell bc you're a HIMSAGI fan.
I think you are Wrong(Originally,there is a rude word,I update it)
We have wronged you, zxyoi.
I remember he did it on purpose.
Maybe it's because he's forced to admit it, lmao... Anyway, he did it on purpose but this contest is just an accident. However that doesn't change how its looks for most participants: they can just easily copy-paste code and get AC, and it's even easier to find the solution for this problem.
We should be grateful for all the problemsetters, even though sometimes the problems are not that perfect. But think of that: Will you make a round unrated if thousands of people cheated together in the round, I think the answer is yes, because the innocent participants' ratings would get affected otherwise. And so is it in this round, many people didn't read the terms of participation, true, resulting in a similar scenario. We want a round go unrated doesn't mean that we don't like the round at all, maybe one problem makes the round unfair, but we still enjoyed rest and we respect the problem providers. However, even if it's not intentional for the problem to be original, the round should be unrated right?
Subjectively, the author did not intentionally repeat the question, but objectively, the repeated question did affect the fairness of the competition. I think the best way to deal with it is to let the competition unrated, and the person who made the question should be treated as making a small mistake.
I think whether or not the problem writer is intended, this round is unfair for most of the participants. What about Skipped this problem? F is a really hard problem. I think at most 10 people can solve them. But now we have 100+.
sb
I still think it should be unrated.
I think everyone who copied the problem F code should be skipped.
According to Rule about third-party code is changing, it has no reason to be skipped.
So what will you do for plagiarists? Nothing and rating as usual?
zxyoi if you didn't admit then it will be alright lol
thats funny
poor zxyoi lol
I don't think that whether the competition is rated or not is necessarily relevant to the feelings of those who prepared questions for the competition.
But definitely, those who participated in the competition are affected and their experiences in participating are clearly ruined. This should be the focus.
I think nmsl
Which problem was this about?
F. It's almost same as 765F.
F
Because of Codeforces Rounds are online, so we can copy the code from the Internet very quickly.
That mean, if you didn't know this problem before, you will get fewer points than people don't know how to solve but copy the code. It makes the contest unfair.
Disagree. If the problem has the similar(same?) trick as another problem, do you feel unfair?
I mean the problems like F that are well-known and can pass by copying the code from the Internet and make small(even no!) change.
My English is poor :(
Also a bigger problem in my opinion is someone wrote a blog on it and even greys copied the code for that question and solved F.
Do you know QQ?
if(predicted_delta < 0) cout << "I think it should be unrated.";
else cout << "I think it should be rated.";
Rational, pertinent and objective
deleted
My predicted delta = 38,but I think it should be unrated.
seriously?
Yes.I solved ABCD and I didn't solved F.But I think it should be unrated because of a duplicate problem——it caused the contest unfair.
I agree with you.
I was replying to tn757
Oh,I didn't know it.Sorry about that
I think it is acceptable to unrated but the F should be removed, because there are so many copies :(
+1. I think deleting problem F will provide justice.
I was completely surprised by you,Mike.
This game rating is not fair to the players.
But problem f is not just similar to the past problem, it is exactly the same. Also, since question f was the original question, not everyone participated seriously in this competition.
Next time, copy the problem and say you are unaware.
Shouldn't we make a clear rule for these situation? I see some contests became unrated but some were still rated when someone found the same problem.
Correct, direct, pertinent, elegant, objective, complete, three-dimensional, comprehensive, dialectical, metaphysical, appreciative of both refined and popular, point-blank, and direct.
There are two "direct" in your words.
I think the blog outlined a clear rule pretty directly.
basically the rule depends on the writer comfirmed what he did. since the difficulty to reach yellow is becoming lower and lower(especially by cheating), i believe that some guys will break the rule one day.
But how can we judge whether the author deliberately or accidentally set a question appeared before.
I agree not to unrated the whole contest,however it will be ridiculous not to remove the problem after awared of the coincidence.
You are right,but Genshin is an open world adventure game produced and published by Shanghai Mihayou Network Technology Co., Ltd. The game takes place in a fantasy world called "Tivat". Here, those chosen by the gods will be granted the "eye of the gods", channeling the power of the elements. Players will play a mysterious character named "Traveler", meet companions with different personalities and unique abilities in free travel, defeat powerful enemies together with them, and find lost relatives — at the same time, gradually discover " Genshin " truth.
6
9
6
about 200 people just Copied the editorial and got AC，it's not fair to make the round be rated.
Can we just remove problem F from consideration?
great idea
I also could see someone who only get accepted in the problem A，B，F.And they got higher score than me XD
Don't unrated please! I get the highest score that I have ever got in this contest and can absolutely get 1600+ which I have been long for. It will be so depressing if unrated.
so it's better to delete F xd
Yes I can understand you because I already experienced it but the fact is the round should be unrated because the F breaks the fairness of the round.
It would be cool to have some kind of automated system which would check problems with the same input/output formats and check if there is a match. Not sure how much work will it be to implement and how many cases will it be able to prevent but it's an interesting idea.
I think copying and coincidence are two different things -- totally different. We have already many problems covering various topics and tricks, it's common to find a similar problem with yours, so I support still rated this round.
I agree with this post, but I also want to point out that the comments in the announcement blog pointing to the copy of Problem F were up for atleast 25 minutes.
For sure, those who commented violated the terms of competition. But the admins should have been prompter in removing those comments. You just took unacceptably too long to delete the comment. A non-trivial fraction of the people who solved F were not from memory, but from the comment that you are talking about.
Yes, but CodeForces is a great platform to practise coding and have good contests.
I agree that we cannot blame the authors and testers for this. However, it would be one thing if only the people who actually remember this problem solved it: I doubt the solve count would be much different. In this case, though, many people solved this problem because they found out about it from the people who posted comments during the round. I do not see how this differs from mass cheating, and I think it is a good reason for this round to be unrated.
To the author of the contest:
I think you are irresponsible about the contest.
Here are some good games you should play: 1. Genshin impact 2. Arknight 3. 三国杀 4. 王者荣耀 5. Minicraft
If you admit you are an OP , our genshin impact players will put you in a good word.
sb
No one wants the round to be unrated (directly) because the authors make a same problem, and everyone understand making a same problem is sometimes hard to avoid; we want the round to be unrated to avoid unfair between participants who already knows the same problem and can copy a code and who doesn't.
It is unfair.
you must be a genshin plaer.
upvote zxyoi god pls
water235 too
I'm a simple man, I see Makise Kurisu, I upvote
Hello Mike, thank you and your platform for all the great contests. I have taken more than 100 contests up to now.
I agree that all the problem-preparers' efforts should be respected and I don't think the problem-preparers copy the problem F on purpose. I am grateful for their nice problem E.
However, why we contestants want it to be unrated is not that we dislike the authors and deny their efforts; it's that too many people get their rank and rating by copying codes online, and too many innocent contestants lose their rating, just because no one tell them there is a same problem in codeforces or that they feel guilty to copy a code.
In ICPC contest, even if there is any same problems, no one has access to the Internet, so only those who really master the problem can solve it. I think it's fair.
But in codeforces, maybe someone didn't solve the problem before, just because his friends tell him here is the code and he solves it through this way. Don't you think he doesn't deserve the rating?
All in all, I respect all the problem-preparers, but I think the round should be unrated.
I don't think so.
We won't blame the writers.But I think it isn't fair to be rated while sb. use history code even others'.
我们不会责备出题人。但是我认为当有人使用历史代码，甚至是别人的历史代码提交答案时还要rated是不公平的。
No, this is within the rules. The rules said that you can use code that is published before contest. Other peoples' code are published before contest.
I think lots of users think this contest will be unrated,so they didn't use the code before.How can it be fair?
我认为很多用户因为认为这次比赛将会unrated所以并没有使用之前的代码。这也是公平的
吗？
so make it unrated lol
Nothing with the authors, I trust them and this does not look deliberate. The money or something for the authors should be kept or maybe even more than kept for compensation or something, they made a huge effort, I saw it from the problems and appreciated it. But this is an online contest.
Yes,I agree.I just think it won't be fair to be rated.If they still want to rated,I just want to say:"addd,you are right,you are right all the time."
是的，我赞同。我只是认为rated是不公平的。如果他们还要rated，我只能说：“啊对对对，你说的对，你说的都对”(乐
Mike, you are right here but just think many of the participants thought that round will be unrated (because in the past because of coincidence in problem rounds turned to unrated) and rushed round or left round in between what about them? They will get a high negative delta after it, is it fair for them?
The author did great I personally liked problems D and E (didn't solve them during the round).
You need to play Genshin Impact.
It is not a punishment to the author to make the round unrated. It is not their fault if the coincidence was unintentional. But the round should still be unrated because a select number of people solved a problem highly above their rating because they were lucky enough to see a comment linking to the solution.
□□□□，□□《□□》□□□□□□□□□□□□□□□□□□□□□□□□。□□□□□□□□□□「□□□」□□□□□，□□□，□□□□□□□□□□「□□□」，□□□□□□。□□□□□□□□「□□□」□□□□□，□□□□□□□□□□□□□、□□□□□□□□，□□□□□□□□□，□□□□□□□——□□，□□□□「□□」□□□
Do you have English version of it? （）
9
If the round is rated, will F affect its fairness?
Even if the score of F is removed, won't there be someone who has less time to finish the other problems because of F?
I think it's totally different from ICPC contests. In CF, we can easily find the problem it is the same as. So, in order to get higher marks, we'd better go to look for the old problem instead of solve the problem, if we hadn't seen it. In fact, it is encouraging participants to cheat. I don't think it's fair. Obviously, we have no way to do similar things in ICPC.
Can I always put on a well-known problem and say "I didn't mean to do it" ?
I. There's something called tags, which gives us a reasonable number of problems to check.
II. No one should take the blame. The probabilty takes. How does someone hit by lightning do something wrong?
III. Consider the participants. Why don't you? There must be a lot of people who had a hard time getting a chance to participate in a Codeforces contest. But with the third-party code rule, they have a bad experience on Codeforces. What would people think of Codeforces?
Yeah, downvote me, ban me quickly. I am just in a mood to shitpost.
I trust the ethics of contest authors, that they didn't do it on purpose. But hundreds of people just finding out the original problem and submit the copied code to get "Pretest Passed". This is very unfair to any other comply with "terms of participation". So I think we should "skip" the cheaters to keep the contest fair. I can't accept the contest rated with these cheaters that copied F.
If a code is copied by many people, the person who copied it first will be rated?
Duh. This is stupid, I downvoted myself using my alt
so what's your opinion on cf contests (?)
The chinese part is mozheng. the above is real. sorry for confusion
Shame on u and cf round.
I have an idea — Make this round unrated. In the future, ban users from creating blogposts / comments during rounds.
The Codeforces community must not make this mistake twice, and disabling blogposts / comments during rounds relegates such unfairness to the shadow realm (aka cheating servers).
Good one. Maybe make a simplistic UI for the current contest like m1.codeforces.com or something, and block everything else. Personally I find the lightweight website setups comfortable during contest.
Do you know QQ？
AGC061 is on.
delete
So how will the plagiarism check be done for this round? Many who passed problem F simply searched for "CF765F" on the internet and got a piece of passing code, so how many of them do we skip? Or maybe not at all?
If a lower problem would have been copied (like D or C), would this discussion still take place? The round would have immediately become unrated, a lot more people would have been affected by this problem. In today's round, there were fewer (but still many) people affected, but the situation still remains unfair nonetheless, and making it unrated (or removing F from the standings) is the more sensible option.
I'm so happy COZ I didn't take part in this competition
There exist a problem is that how can we know if a problem was matched unintentionally or not.If I just read the statement of the old problem and prepare "my problem" by myself,it's hard to find strong evidence to proof I did it on purpose.
No one should be blamed ,but it's unfair if it's rated. Mike Never Mind the Scandal and Liber❤. And I advice you to play Genshin Impact:)
Another question:why someone search for F
Maybe someone remember it and don't need searching. After all the problem statement is equivalent to one short sentence "Query the maximum of difference in some interval". It's easy to remember it if you have solved some similar problem.
I also agree that the contest should be rated, especially because this was a div 2 contest and there were only 250 solves of F. The main groups of people who are affected are:
the people who found F online and resubmitted who will get a large positive delta.
those who finished A-D quickly and attempted to solve F instead of E, which may be easier. Or those who solved E and now are ranked way below where they should be. These people likely get a positive delta anyway.
people who did not solve A-D quickly, who are unlikely to solve anything higher than D. these people will get a slightly more negative delta on average since there are F solves that shouldn't be there.
One potential middle ground would be to calculate the ratings twice: including problem F and excluding F, and then giving people the higher of the rating deltas. This would benefit groups 2 and 3, while leaving group 1 the same. I'm curious how much rating inflation that would cause. If the avg. rating increase per participant is not too high, it seems reasonable. Or maybe that's too much work, which is also reasonable.
Note that I am biased, since I was in group 2, which is the group that benefits the most from such a change :P
In reality though, rating is just a trailing indicator of skill, so it shouldn't be a big deal no matter what. Thank you for the contest and the great platform!
Is 250 a small number for Div2 F? I solved E and I think it not a hard problem,however there's less than 50 correct submission to E.
Oh sorry, i didn't mean it's a small number of people compared to how many should have solved it. I just meant compared to the number of people who took the contest (~2.5% of the rated participants). People that are outside the top 10% won't have their rating affected toooo much, and people in the top 10% are more likely to have a positive delta.
To me, the main argument for unrating the contest is to make sure those in group 1 above don't benefit unfairly. But if they performed way above their skill because of it, their rating will just go back down in a future contest, so it's not a big deal to me.
this is actually a underrated good suggestion
I wonder... do the writters really write their problems to 'rate' people? But I believe participants are here for a clear, fair, and 'rated' round. (If not, why are they participating on-time? They could just solve archives/virtual)
I cant really see the downside of unrating the round. Even though unrated rounds makes me weary and empty, I'd prefer fair rounds and points.
+) I do understand that coordinators/staffs may feel pissed. Thank you for such a great platform
3000+ score is just determined by whether you checked the comments early — is it fair?
I don't think that the authors, the coordinators or the testers should be to blame. But, many contestants have seen or solven the old problem. They can just copy the code they wrote before, or even just copy someone else's code to get the points. It's of course very unfair. The old problem is well-known, and I thought that such a amount of contestants who get the chance to copy code is a problem big enough.
i wish unrated (because i will -100 after this contest). But I believe Mike's decision is right. Moreover, codeforces has provided so many great questions and I learned a lot in it. whether it rated doesn't matter.
Was it intentional or careless? I kept part of the original question, you know you're participating in codeforce.
I removed most of the original questions, but kept some of them, because I think it can let you know that this is codeforces.
No, you are wrong about this.
I didn't write that recognizing a round as non-rated is equivalent to admitting the authors' guilt. I warned that the authors and coordinators cannot be blamed for what happened. I've erased some very nasty comments and wouldn't want that tone to become the norm.
Of course, the situation affects the standings. My idea is that such a coincidence is a probabilistic process and over time, problems only accumulate and this probability grows. And we have to live with it, we cannot rule out the possibility of this. We need to somehow fight, try to prevent, but move forward. And the use of the rule: the problem coincided, so the round is unrated is not a solution.
It's like about cheaters. I clean out hundreds of dishonest contestants every round. And, of course, these numbers are growing. Let's make the round non-ranking as soon as someone publishes their solutions in the next stupid telegram channel? It's like accepting the conditions of a terrorist, knowing that he will repeat his actions again and again.
I think it may be a solution if you update the rules and add the limit of problem coincidence into it. For example, you can decide that if there is only one bad problem, the bad problem is not so famous, or the problem is from a contest that was hold a long time ago, then there won't be a unr.
It is not like about cheaters. Cleaning out cheaters can restore the fairness of the contest, but cleaning out coincident problems can not, so we should make the contest unrated. If cleaning out cheaters is a solution, making contests unrated should be one too.
I understood what you mean. I think our logics are both self-consistent, but I still want to express my follow-up views.
All of that is of no use if people think that screaming "OMG THIS PROBLEM IS FROM XXOI 1969 HERE'S THE LINK" into the comment section is good.
Just think of the candidate masters/experts, they solved problems till D/E by their own and now they are getting much lesser rank than they deserve.
sorry,zxyoi.
Is codeforces the next FJOI？
No,it's the last FJOI.Because FJOI is copied from codeforces.
Maybe yes.
At least problems here are solvable.
then how do you know whether the writer plagiarized or it was just an coincidence? What about the competitors who should have had positive rating changes but got negative ones instead just because of those who discovered the coincidence and copy-pasted to pass F?Is it truly fair to them?
Although the coincidence of problems always exists and it is hard to avoid, it doesn't mean that the contest should still be rated. The fact is not every contest has coincided problems, but all the contests which have these should be unrated.
I made some problems before and I also created problems that coincided with others(luckily discovered by myself).But I don't think this can be a reason to keep the contest rated.
Actually I don't think it is that bad of a situation. If a person have somehow solved that 5 years old question and managed to remember that in a contest with a similar question, which happens extremely rarely, I think that guy deserves it. I mean a lot of questions are similar anyways. After thinking 5 minutes on a problem a lot of questions become the same anyways.
I could understand that the authors had paid many efforts, but I still think it's unfair that hundreds of participants solved F only by copying codes from internet. I think something should be done to make this round fairer.
https://mirror.codeforces.com/blog/entry/106700
Is it fair for the authors who made amazing problems but it's unrated due to one problem? and now this round is rated?
I think the distinction being made is that in the previous case the problem was knowingly copied ("stolen" is the language used), but in this case the duplication was unintentional. See https://mirror.codeforces.com/blog/entry/106697.
Maybe it would be a good idea to shut down all blog activity during rated contests.
This does not look like a solution, but sweeping the problem under the rug. Now there are a million other ways to communicate on the Internet.
But yes. Probably the comments/posts need to be moderated more actively during rounds.
How can a contest be rated with a so classic problem? How can so many contest writers and testers being unaware of this classic problem? By the way, the ICPC last week(Hong Kong Regional Contest) has a problem named Range Closest Pair of Points Query in 2D.
You are right, but our compressed towel is small and convenient to carry. When you open it, it will become bigger when you put it in the water. It can't be torn apart. It is easy to use for wiping feet, face and mouth. You see it is as big as a round cake after you open it. It will become bigger and higher when you put it in the water. It has strong water absorption. When it is opened, it is a thickened towel. You can see how he can earn it and how he can make it. It's fine to use it seven or eight times. It's very convenient to take it with you on business trips. Wipe your feet, mouth and face with it. It's clean and sanitary. what? Where can I buy it? The small yellow car below, buy five bags and get five free, and return the package
skipping F is the best choice over making the round unrated
Yes, there is nothing wrong with the organizers of the competition. There is no need not to unrated. Participants who are treated unfairly should smile.
Fair competition? That's nothing compared with the efforts of the organizers.
Could AI (perhaps LLMs) be useful for retrieving similar problems (like a search engine) to the one being proposed in a contest? Could an AI-based tool designed for cf be helpful preventing such coincidences beforehand?
Read this
I think this idea is very constructive.Wish someone could develop such an ai.
<-deleted->
NO, I got a low standing and it means the contest will still be rated and I will get a negative rating changes...OMG
You maybe right, but I don't care if you were intended or not. That is sure that this competition had the original problem and it were severely affected score. You should apologize and find a way to reduce impact but not explain you were unintented.
correct zhongkende
If you can't make the round unrated then may be you could calculate the ratings by excluding the F problem.
Support it. However, I personally prefer to remove F from the contest instead.
There are two kinds of people who solved F. One are those "participants remembering a wide range of tasks and knowing how to put them into practice", but another just got some information from social media, searched this problem on the Internet and then just copied someone else's code.
The latter are those we definitely criticize. Certainly removing F is unfair for those who solved it themselves, but I think they are capable enough to afford such rating changes about just one problem. (I am a newbie, and I believe those who can solve F independently are all at the level of orange or red)
Positive Solution.
Although removing F is unfair for someone,I think this is better than leaving the round unrated.The remaining part of the round is still creative and challenging.Besides,problem F did influence the round's fairness.So removing F is deserved.
Preparing a Codeforces round is really difficult.No one can avoid making mistakes and the writers are not intentional.
In fact, quite a few people are annoyed for we actually CANNOT confirm that the writers "are not intentional". They think Mike is kind of protecting "his writers" without any evidences. After all an F solved by 300+ people is truly unfair.
But for me, I prefer to believe the writers are innocent. I also wrote problems for our school contest, so I understand that each problem is precious for writers. I can't imagine why a writer chose to make such an incident intentionally. Everyone clearly knows that wouldn't be nice. Do you believe the writer was dying for our criticism so that he did this?
By the way, another version of this problem in Round #397 is kind of different. The array in today's problem is a permutation while another one has no limitations. That's one of the reasons why I believe this is just a coincidence.
upd: Sorry for a mistake. The early version of this problem is numbered 765F in the problem list, from Codeforces Round #397, but I mistook it for Round #765. PS: I have never understood how are the rounds numbered. I tried to find the rule but failed. The numbers don't even follow the sequence of time.
Yes,most of the writers truly want to give the competitors a wonderful round.For example: https://blog.csdn.net/VFleaKing/article/details/90521383 https://blog.csdn.net/VFleaKing/article/details/90522020
Thank you very much, I've just read the whole story.
Preparing a round is quite admirable work. Thanks to all the authors and coordinators on this amazing platform.
As for the feelings of the author, is it more important for him that his round remains rated or that his round was pleasant for the contestants or not?
It's amazing how some people who solved C after 90 minutes, failed to solve D, have their solution for F accepted in under 30 minutes. hehe
I don't know if this should be rated or not, but I am definitely considering giving Genshin a try!
Maybe you should swap these 2 parts as you want to say something meaningful.
I think we need a more clear set of rules to distinguish between rated and unrated competitions.
Totally disappointed. You say that such a problem coincidence should not be unrated and you are strongly against the creation of such a precedent.
That may seem acceptable, however, have you thought about the consequences of letting it be rated? Then anyone can create a similar problem and say "I don't know the original problem before.".
If the contest is rated, I think Codeforces will close down soon.
Problem F's name is a notorious coincidence
Without subjective factors, objective factors are also important. Codeforces is famous around the world because not only the high quality of its problems, but also the fairness and justice. There is no doubt that problem F makes this contest unfair. To make this a fair contest, unrated this contest is necessary.
Were there any comments removed?I see the total number decresing.Why?
why not unranted.
After seeing so much of CP resources in Chinese, I wish that I knew Chinese.
I hope one-day Luogu will be launched in English too.
Shut up, Luogu contests are more of a trash can with some gold buried and there are ten times more errors in those contests. They fix it in the middle of the contest every time. In Codeforces this doesn't happen a lot so whenever this happens people go berserk.
Codeforces is still the largest and probably best OJ in the world now. Luogu still has lots of catching up to do. Broaden up your horizons and see the world.
Some good problems are on luogu but not CodeForces.
They are both nice OJ.
I warn everyone who is reading this comment that the Chinese Version is completely different from the English Version.
edited
The Chinese version is more unfriendly in this context.
The Chinese version is more accurate and unfriendly in this context.
To be honest,Question F has nothing to do with most of us.The number of people who solved the A is eight thousand.And the number of people who solved F is only three hundred people.Most people struggle with the questions before D.We have no time to solve F.For me,I never read the F problem and even after all kinds of round,I just try to solve A,B,C,D and E.And in addition,as a Chinese people,most of the rounds in China is very late.Most of the time we stay up very late to participate in the round.So we very cherish the round which is friendly to us.I agree with MikeMirzayanov.
I did read F and wasted half an hour of my time on it, because the number of solution was higher than E so I thought probably it's easier than it looks. So, removing it is unfair to me, and others who spent their time on it.
Maybe we should close the blogs and comments during the rated contests. I think this can reduce the number of cheating.
I am shocked by such a great number of impolite, unrelated comments in this post. And moreover, most of them are from Chinese high school students. If you want to share your view, it is fine. But what’s about those bad jokes and offensive words? I understand in your community, you guys have your own ways of spamming, discussing and thought sharing, but please don’t bring those trash (yes, I say trash) to everywhere. Before trying to be a good CP competitor, please learn how to be a decent person first.
You are right, but Gensh...
This is called the rubbish of Chinese online community, as a Chinese I can't agree with you more.
Maybe there are some misunderstandings, "the rubbish" is the rubbish joke, not people
Forgive my poor English please :(
lol probably most of them are like 13 years old or something. Chinese high school students regard them as monkeys.
Can't agree more. I just don't understand why they are talking so impolitely.
Agree. We should use logics and reasons to argue.
You are right, and fight them with downvotes.
I think it's a problem of the level of trash in the posts. I like it if it contains useful advice or arguments, plus some jokes. But I hate it if it only contains bad words or meaningless jokes. So is Genshen Impact really so interesting?
I understand, but disagree.
We made rounds unrated because those coincidences greatly influenced the fairness. As a matter of fact, hundreds of people have passed F, which means the round should have been unrated according to the rules.
It should be judged not by sympathy, but by rules.
Whether you agree that the contest should be unrated or not, you must admit that determining if a problem coincided with one another is getting more and more difficult with the increase of problems. We are human, so we can't remember all the problems.
So why not develop new techniques to check the problems? One way is to create a database of problems, where formalized statements, solutions and so on of almost all the public problems on the Internet are provided. And we can try to invent a bot to check if a problem coincides. Then at least we can reduce the problems coincide with those already exist on the Internet. Of course, no one wants to argue like this every day!
What the actual f**k is this comment section?
I get that many people think that the round should be unrated. And I am one of them as well. I don't agree with Mike's decision, neither do I agree with the reasoning behind it.
But what disgusts me is how many people think that a wrong decision which affects their rating is a good enough reason to insult Mike or his relatives, to call him an idiot, to wish for CF's collapse and closing. They have no moral rights to say these things.
I wonder why many found F during the contest.I don't think it is so well-known a problem,and I may even didn't have a look at F during the contest(at least before I solve D).
Some contestants posted the link to the original problem in the comments of the announcement during the contest (which were removed quickly). I think many contestants saw these comments and copy-pasted.
And I know some of my classmates solved this problem some months ago,they public the link with other classmates,so I knew it is an original problem 12 minutes after the beginning of the contest(Although all of us didn't take part in today's contest.)I think maybe many contestants know by this way.
At least all of my friends realized it after we read this statement,I think this problem is really classic.
Except me lol
f_AK_e.
I totally agree. Could anyone tell me which problem we are talking about? And what is the problem it coincided with?
Yes, you're right. But codeforces is a Russian website developed by Saratov State University to provide an online evaluation system for enthusiasts of computer programming.
and I also remembered there was a Div1 happened similar situations,and it was unrated.(my first participated Div1)And that was an AT's problem.
Why the two has different results?Because it's still unkown whether the problem provider did it on purpose or by mistake?(At least I don't know yet.Maybe I missed some important information.)
If a contest is unfair, we should make it unrated, which does not mean that anyone was wrong.
Here's why.
based on Moscow Olympiad for Young Students
Anyway, A,B,C,D,E are nice problems. Perhaps removing F from the contest and make the round rated is a better choice, which avoiding the impacts of the problem coincide and respecting the authors's hard work as well. But that is only my opinion.
Hope such cases will not happen in the future any more.
If unrated is the insult to author's effort, rated is the blasphemy to fairness.
Enough philosophy for me today.
Can i have a link to the original prob of problem F?
Does an ACM-ICPC contest cancel its awards and eliminations if one of the problems is intentionally copied?
Because this Div.2 Round I has just begun to learn and discuss Competitive Programming on CodeForces, I feel that the questions are very beautiful, with very novel ideas and very enlightening solutions, and the atmosphere of the discussion area is also very friendly. I look forward to more high-quality Div.2 Round!
Never expected Mike to make such an illogical argument (・o・)
No. But they should remember this problem.
Alright, let's have a look.
So far, in Luogu, the most famous OJ in China, there are over 2k submissions, 19 solutions for problem 765F. This is not a small number.
Not to speak of there exists another similar problem.
In the other hand, how could one submit the correct submission for F just 3 minutes after start?
If the contest is still rated, okay, you're right, but Genshin Impact.
1.There is a rumor that CF has the original problem. Let me clarify that this is not a rumor.
2.New users may not know the value of CF coordinator. I will explain it here. Old users also do not know.
3.Half of CF users are cursing the original problem. I feel very angry about it. Is the other half not talkative?
4.Someone said that CF is an equal and free academic discussing platform. I checked and found that Mike said it himself.
I cannot agree with your point of view. On Chinese contest websites, such behavior can lead to the question maker being held accountable and banned from submitting contest problems again. Once there is a case with the same topic as before but not unrated, there will often be poor quality topics in the future, which is very bad for CodeForces.
And obviously it's different from ICPC.
As an offline competition,you can't easily find the code,copy it and submit.Just like many problems that they have the same way to solve but a bit difference.Although you may know how to solve it as soon as you read the statements,you still must be very careful with the details in your code.
But as an online contest who cares?The solutions on the Internet can help you deal with these details and all you need to do is just to copy the code and submit.
If it was a offline contest, the problem coincidence might have less influence.
But it is an ONLINE CODEFORCES contest, the problem provider HAVE THE RESPONSIBILITY to check that wheather there's a same problem in past contests. And problem F is a very well-known problem, as far as I know, at least 60% of Chinese who's good at data structures used to solve it, it even appeared in a past codeforces contest. If F was not so well-known like that, I would stand on Mike's opinion, but obviously the problem provider didn't take the basic responsibility of providing problems. It should be unrated.
If you want to provide a problem, a good idea is important, to avoid problem coincidences is also necessary.
If you don't have the ability to take those responsibilities, then don't provide problems, you are not a good provider, solving your problem is a waste of time.
I agree with you that it should be unrated, but can I ask a question? How to check if there is a same problem in past contests, given that there are almost 8500 problems on this platform (as Mike said)?
You could refer to what luogu is doing, they invite many problem checkers to check that. the checkers always be good at this knowledge or used to solve many problems of this knowledge, then they can avoid having the situation of problem F.
Luogu is a Chinese Online Judge, the website is www.luogu.com.cn . It's all in Chinese, if you want to use it, you may have to use a translator.
Of course that problem coincidences can't be completely avoided, but avoiding the situation like problem F is achievable.
Maybe finding the original problem is also an ability, but that is NOT what we really want. Also it is unfair to copy the code or communicate about its original problem.
This is just a suggestion, don't know how helpful this might be, if a ques already appeared in a round before, we instantly know about it after the contest ends,the main reason for that most probably is that people try to search the question on web and see if a similar ques exists, well this type of searching can easily be done now by using AI softwares like chatgpt etc.
So my suggestion is that the testers can test the originality of the question by asking chat gpt or any other Ai to solve it, and since the AI tries to solve the question based on the past data it has been given, if the AI solves it we know for sure the ques has appeared before and the ques should not be included, but if it is not able to solve it, we are not completely sure that the ques has not appeared before but we can verify it's originality upto some extent.
Thank you
I respect and appreciate the efforts of the authors. Such coincidence is not their fault, or anyone's fault, who prepared this contest. However, it is responsible to do something with the current situation. Most participants are honest. Their ratings may be affected by the result of these accepted submissions. Making this contest unrated may be one choice, but may not be the best one considering multiple factors. I hope there are some regulations or procedures to deal with such scenarios, or maybe it is acceptable to provide a proof that the influence is negligible.
You are right.
.
You can see most of them who solved F also solved A-D,or solved A-C very quickly.
If one cannot solve D and more,those people has very little influence to his final standing because even without F most of them is still ahead of him.
But for those ratings over 1800,especially for CM,they can always solve D.In that cases their standings will change a lot.And if you experienced CM times,you'll find even 100 standings different will cause a lot to your rating changes.
Thanks for your effort. But I think it's not important to discuss whether to rate or not. We should pay more attention to avoid it happening again. Maybe we can refer to the formal examination. In my country, the authors of a test will prepare two versions of test paper. If something unexpected happens, we can use another version. So I think codeforces can do something like that too. If some problems are wrong or plagiarized, replace they with the problems of similar difficulty prepared for next contest and extend the time according to the changes of problems and when they are replaced.
I think , all this is happening because I almost became pupil.
Anyway,what I'm dissatisfied with most is neither whether the round should be unrated,nor whether the provider is on purpose or not.
I'm really dissatisfied with is the attitude when a behavior break the rules.
Okay,it's hard to build up a contest,but now it really break the rules,and you tell me that because it's hard to prepare a round,you'll keep it rated?
That's not the point!The fact is that it really break the rule.
Since you have this rule and really used it several times in the past,why can you have this one exception,or you want to change the rule?
Thanks，I got cm！
You need to play Genshin Impact.
Thanks to this round, I've gotten a highest scores in my programming constest life. In the past, I have never solved more than 3000 scores in any round. My ranking has never been so high.
Nothing, I know my level is not high, so you can scold me. Maybe I know I've done it before, and I still don't write according to the original? Then what is the meaning of my former constant practice? Alas.
So why someone upvoited this post?
Yeah writing in the comment DURING the contest that the problem is a variation of a previous problem... Thats not cool.
As my know, Mike removed some comments that have no problems but are bad for his team, is this on purpose or by accident?
Since I am just a fucking Expert, I still have ability to give this fucking F a downvote.
If you want to remove my account, welcome!
You, Your Team even the whole CodeForces will be well-known as tyranny!
I do find this statement similar to something.
still upvoted btw
Those comments are overly offensive and contribute nothing to the topic. I thicnk we do accept rational discussion, whether they support Mike's opinion or not.
Why not use Luogu?At least they will not shirk their responsibilities and protect the short.
When Luogu users suggests to "learn from CodeForces to be better", they would never imagine that those partial things would happen in CodeForces one day.
Whether the round is unrated or not should never be linked with authors' efforts cause the rating system is just for trainers see their or others level in a rough way.
Yes. Contest which has duplicate problem(s) in Luogu will be unrated and as soon as the contest becomes over, writers and coordinators of this contest will make a apologize to all contestant instead of explaining it as a coincidence and keeping it rated. Administrators also attach great importance to this and will make a public statement at the first time. They just use simple words to discribe what happened and begin finding out if writers is intentional or careless but not give such a long artical to say things like these. After the truth becomes found out, the writes will be punished if they really copied the idea of a problem they know. If not, nothing will happen to them. I think CodeForces should learn from Luogu in this side.The attitude towards contests with duplicate problem(s) shouldn't be like what this artical says. If the real reason is the writer is from Russia, everything will become reasonable :P.
Contest which has duplicate problem(s) in Luogu will be unrated and as soon as the contest becomes over
Are you really sure about that?
Maybe I should blame the machine translation for it, but I've tried reading several problems from latest rated contests on Luogu (I don't know Chinese, so I had to use machine translation), and some of them seem very well-known and classical to me.
If you're sure about that you've seen any problems in rated contests, tell me please. I will tell the administrator if they are duplicate problems, then they will make it unrated.
But there's a fact you have to know: simple problems are easy to be duplicate, and it won't make great influence. For example, there's duplicate problems in AtCoder Beginner Contest sometimes.
Okay, let's take this problem, for example. Is my understanding of it right?
You are given an array $$$a_1, a_2, \dots, a_n$$$ and an integer $$$m \le n$$$. Find the minimum possible integer $$$\epsilon$$$ such that it's possible to choose exactly $$$m$$$ elements $$$b_1, b_2, \dots, b_m$$$ from this array so that the condition $$$|b_i - b_j| \le \epsilon$$$ is satisfied for every $$$1 \le i, j \le m$$$.
If this is correct, then it's definitely a well-known problem. I don't think this is enough of a reason to make the contest unrated because of them (and I definitely don't think luogu should retroactively make this contest unrated), since, as you say, simple problems are often repeated. But it contradicts your original claim that as soon as a contest with a repeated problem is over, it becomes unrated.
That one comes from a contest for beginners. A "normal" contest looks like this.
Yes, you're right. It just like codeforces Div.4 .
If you can find out the specific problem which this is same as in any famous OJ, I will tell the administrator right away.
pretty sure.
Although Luogu is not as good as Codeforces in some aspects, they at least respect the contestants and the topic, not just defend themselves when some unexpected things happened
Being unrated doesn't mean that problem writers' work is wasted, while it does affect whether the round is fair or not. The efforts of the writer are not an excuse for the cheaters to get higher ratings. What about those who did not cheat? The writers and the testers should be responsible for their round.
Since I am just a fucking Expert with fucking Low IQ, AQ and EQ and can be CM if this contest don't be unrated, I still want it unrated and stay at fucking Expert with my low IQ!
To be honest, I don't very care if this round will be unrated, even if the CF-Predictor gave me a negative delta. Even if maybe someone copied code and makes me get lower rating, I think I can just gain them back in the next rounds because imperfect rounds are much less than good rounds.
But don't unrated this round will show people that if you have high status you can do anything you like and just say "NO! You guys are fucking wrong! I didn't mean to do it!".
And if you aren't famous, your round will be unrated even you prepare it for half a year!
I feel that Mike's argument is backed by logic, and we must understand that making the round unrated is not a solution for such a case, and it won't mean that it doesn't happen again.
Hence I propose that the points for the problem under consideration should be reduced so that the standings are fairer, the people who actually solved the problem get due credit, and impact of non-deserving points received by others is reduced.
When you findout some problems are same to some old problems, the participants may already findout it and start communicating. That mean, they may think little of this round and talk about other problems.
So I think the best way to solve the problems like problem of this round is inviting someone from different countrys and rateds to take part in the contest before it start and ban them in the official contest and pay them some money for doing this.
If someone managed to remember this exact problem from a contest 5 years ago, I think they do deserve some points. Just saying.
I didn`t participate and when I see the F in this contest I was shocked...
It has 2 almost identical copies in Codeforces(CF765F) and Luogu(P5926)
Although I know the original problems I still want this to UNR because I forgot to participant this is unfair to both kinds of people:
- The people who don`t know the original problem.
- The people who know the original problem but didn`t participate.
The occurrence of original problems and some comments which didn't got deleted quickly enough did broke the fairness of the round. And if the round is rated: someone will get rating that doesn't match their real strength. Maybe it will become smoother and finally disappear as time goes by, but just like these words in the post: In any other case, it will sometimes happen. If it did not happen today, it will happen tomorrow. All we can do is make some effort to prevent it. Then the crush of the rating system is something serious and persistent, because it's the crush of rules at its core.
So will this contest be rated?
so, which problem coincided with the former problem?
well, I'll be so sad if unrated. Because I Obtained a better ranking than before without solved problem F.
Actually,I know this problem as same as 765F.I search on the internet,and then I find the answer. I didn't copy it because two reasons.
(1) I'm afraid I will skip this round.
(2) People who copy it have not got any harvest.
Only f**king one competition cannot shows someone's power.If you strong all the time,you wont care about this because you are strong enough to make your rating higher next time.
I hope everyone to make your rating higher next time.
First of all, I want to say that I didn't participate in the contest.
Now that that's out of the way, I have a few thoughts about this situation. I believe the round should be unrated not as an "F you" to the writers/coordinators/testers/participants/anyone, but as an "F you" to everyone who only managed to solve the problem after knowing of that coincidence, so they don't get undeserved rating (which, by the way, is completely pointless because they'll probably lose it in the next rounds). But in order not to set a precedent that would cause many future contest from being potentially unrated just because someone found a similar problem before, and to allow people who remember many tasks to benefit from their training, I suggest the following:
If enforced, at least on the codeforces platform itself and other related platforms (such as discord servers with a lot of codeforces users), this would heavily limit the spread of the news about a problem coincidence, which would lead to many people using that opportunity to cheat. While also being a feasable approach to limiting this kind of behavior. Of course, you can't control if two people talk privately during a contest, but that's what the plagiarism detector is for. But it is entirely possible and reasonable to remove blogs talking about the problems of a contest, at least until it's over.
The main issue here is someone posts a public comment during contest, and 100's people get directed to an existing solution. The poster and their readers are all breaking rules, making the contest unfair.
Otherwise, I totally agree with Mike's reasoning. We must respect the efforts of those making the contest, and we give them the benefit of doubt. Unrating a contest is not implying blame, it's just a practical way of maintaining the integrity of the rating system.
guys ,don't make mike angry
[deleted]
I think there is no point to make this round unrated. Suppose a person who has cheated or copy paste from old code his rating will increase but the question is will he or she be able to increase his/her rating in next round. You all know rating describes your level. So in next contest his rating will gradually decrease. I would surely want to describe my incident when my solution was same as that of some person . But it was not intentionally. At that time i file report against this(that's why my contribution is negative). At that time one person just comment me that if you are true about yourself then you didn't have to prove here. You can prove in next round by improving yourself. Really thanks to that person.
So that's i think there is not point in making this contest unrated. Also we can not give blame to anyone. Even some didn't know about that problem ,even i didn't.
I also think there is no need to do drama here. Mike Sir know what to do.
As much as I agree with you, thinking about what has happened in past cases of similar or blatanly copied problems I'm afraid the best choice might be (as in there's a possibility of it being) to make it unrated.
The thing is that some people's first reaction to such fact is dissing the round in the announcement comments and mentioning which problem it came from. Such behaviour is highly disadvantageous for people that simply do their best to solve the problems and don't care about going to announcement in such cases.
I wasn't awake for this contest so I don't know if it happened, but if it did I see it as a big argument to make the round unrated. Think of it as an exam that had problems blatanly publicly leaked for everyone to see (edit: perhaps the best solution is this case is to remove the problem that got leaked?). I'd hope that in such cases we follow your guidelines but heavily punish people that leaked such problems as in banning them for at least a couple of months up to years if they repeat such behaviour.
..
omg it has been more than 5 hours and ratings haven't been updated , this is unnaceptable !!!!!
"No, all these people have put a lot of effort into preparation. You may have partially lost the buzz from solving the 2-hour round. The authors and coordinator put weeks of work into it!"
So what? It is still their fault, and although we SHOULD, but it is never our responsibility to be sympathy for them. We are grateful of what you do Mike, but please, don't put your personal emotion into things like this and act like a child.
We all want good contests, so we need to appreciate those making the contests and encourage them to do better. Whilst undesirable, it's not fatal to accidentally repeat a 5-year-old problem, the number of people who actually remember would not be large. The real issue is people communicating during contest, which is against the rules. And this issue exists even if problems are new. Contestants communicating online during contest should be punished (banned, rating deducted etc).
Recently, there have been many mistakes in the contests, such as poor tests and similar problems. I hope these mistakes will be fixed. ( Of course, with all respect to the problem setter, And all my thanks to them )
I think the main problem is that the two statements are almost identical, not just overlapping in ideas. And the idea, I have to say with a little offense, seems to be classic (especially for Chinese? idk). I've also solved this problem years ago when learning something called Driver Ji Segment Tree in China.
If a participant realized that or got the news through some other ways, he or she would get a quick AC, which is obviously unfair to other participants.
Unrated is also an unfair choice for the relevant personnel who worked hard to organize the contest, but its just difficult to give a complete justice solution under such an extreme and unpredictable coincidence.
I agree. I think a good solution would be to remove problem F, not the entire set of problems. Could anyone point out the flaw in this?
Upvoting because I feel you're right
Suppose rainboy spends 20 minutes solving F and herd that only F has not been scored.
I'm so happppppyyyyyyyyyyyyyy
Now based on the data, there seems to be more support for the blog. To be honest, the coincided problems of those unrated round almost have nothing to do with me, I can only do A~D, today's round, the time is very friendly to Chinese players, I also came to do it, although the D problem could not be done in the round, but I think the A~D of this match was very good, and I also learned a lot from it. I'm more concerned about what I can learn now than I was in the beginning with codeforces, rather than the change in rating. Thank you very much for bringing us wonderful questions, but I still support unrated this round: although it may damage the feelings of those like me who can only do A~D and want to improve their rating (may be they do well in this round), it guarantees the fairness of the players with high rating. (not good at English)
Oh, rating has changed. Anyway, I still respect your choice.
Sorry for probably bad analogy. But it resemble teachers who give good grades to students who did work hard, just because they did work hard, regardless of quality of result.
Now, my opinion:
So, I support making round unrated. And I disagree with idea to remove problem F, because:
Congrats, we have achieved dictatorship in codeforces.
I've noticed a lot of comments like "problem F barely affects anyone" or "we just should remove F" or "CMs and above should have solved D anyway so just removing problem F would make it fair". I don't believe that my personal experience lines up with these comments/opinions.
I solved A,B,C relatively fast (within 25 minutes), and at this point there were less than 100 solves on both D and F. I read D, noticed a solution, and then quickly checked the solve counts of each problem (I noticed that the solve counts for F were increasing very quickly; when I checked, problem F had around 90 solves while problem D only had 70-80). As a result, I chose to hold off on implementing D to try and implement F (perhaps this is my fault, but it is what I did).
In some way I was very unlucky, because I noticed a square root decomposition solution quickly (which ended up being too slow), which I thought could pass the constraints (since $$$q \cdot \sqrt{n} \approx 5 \cdot 10^8$$$ and the time limit was 4 seconds). The solution involved the observation that either $$$|r - l| \leq \sqrt{n}$$$ or the answer was at most $$$\sqrt{n}$$$. I thought this would be fairly straightforward to implement, so I first tried it with $$$O(n\sqrt{n})$$$ memory (which did not work). I got unlucky again when I realized that the answers could be computed in a different order to use only $$$O(n)$$$ memory, so I spent some time implementing this, thinking it could work.
At this point there were about 40 minutes left. There were about 150-200 solves on F and maybe 400-500 on D (I don't remember exactly), but since I had already implemented a solution and I saw 200 solves, I assumed that it might still be possible to implement the solution in time (also, solving D at that point would have given me way less points than solving F, and I already had a negative predicted delta). Perhaps this was my fault, but with the incorrect solution and the solve count, I was tricked into believing that I could solve the problem.
By the end of the contest, I had reimplemented my solution, but I realized that it involved an extra log factor from a segment tree that I used to calculate part of the answer. At this point I had about 15 minutes left, so I thought about how I could reduce this. I couldn't think of anything, so I ended up not solving the problem. From about 90 minutes remaining to the end of the contest, I felt like I was close to solving F, so I didn't even go back and attempt to solve D.
At the end of the contest, I felt that I was pretty close and I just needed to practice more and upsolve the problem (I was ok with getting -70 delta). I was fine with the result even after realizing that the problem had appeared before. However, after learning that the older problem's link was posted in the round announcement, I no longer felt that the contest was fair. The contest no longer gave an advantage to people who practice solving harder problems, but instead gave an advantage to people who share code with each other during the contest. And somehow, I was caught up in the middle and got the worst of the outcomes of this (-70 delta and false hope that I could solve a problem that I probably couldn't solve given 3 weeks).
For me personally, removing F and recalculating rating changes would probably not have an impact on my rating change. Perhaps not a lot of people are in this situation, but I wanted to make others aware that it could happen as well. I think that the best decision would be to just make the round unrated rather than to try and recalculate the ratings after removing a problem (or worse, to not do anything at all).
I also immediately came up with the sqrt complexity solution soon after I found the ranklist peculiar and clicked into F. And spent an hour on it, expecting higher ranks. Yet also found out it was too slow even under 4sec TL, but it was too late.
The problem is not that a problem coincidence happened but that there was a massive ammount of cheating due to people saying mid contest that the problem was repeated. I think that this is reasonable enough to make this round in specific unrated (and the people who shared that should be banned).
I do agree that rounds that have repeated problems in general shouldn't be unrated tho.
I respect the work of the authors and coordinators, but I still think making the round unrated or rated excluding problem F is better than rated including problem F. This is unfair for those who just cheated to get problem F accepted.
Why are the codes of the first and second-place person exactly the same??
I'm so happy COZ I didn't take part in this competition
Unrating the contest and blaming the writers are simply not the same. I mean the authors have indeed prepared good problems, but I dont think this is a valid reason for not unrating a round with problem concidences
The main issue here is whether to unrate the round or not rather than talking about the author's work, for unrating a contest is not implying blame, it's just a practical way of maintaining the integrity of the rating system.
It is absolutely unfair,especially for those who solved E but failed to solve F.
I think in these days , AtCoder's problem quality is better.
I think we can not define what is problem coincidences, because different problems can have the same key idea that, if you have seen one, you will solve the others easily. Maybe we should have more testers, and let them vote for a scale of rating deltas. A contest containing low quality problems will get a low scale.
rated????????????????????
If I write some problem and share it with my friends and we all solve it, then later the problem appears in a CodeForces round, should the round be unrated? (rhetorical)
Interestingly this has actually happened (believe me or don't -- IDC).
What if some problem from a CodeForces round has already appeared in a much lesser known high school programming contest? Perhaps the CodeForces team finds this out years later and some participants got a "free solve" -- should ratings be retroactively changed to accommodate this? I don't think so. Like MikeMirzayanov said, it's a bit of a reward for solving some problem (yay!), and at the end of the day all participants ratings will resolve themselves in future contests if they are not accurate to their actual skill.
I can understand you. What you said is almost correct, but it is really a little unfair for those who do not find that the problem is a duplicate one.So I think it should be unrated.I believe that not many people pay attention to ratings.But it's a bad precedent.
Although my rating += 38,I think it should be unrated.
if no one had written the comment about the problem, few people could've copied the code. maybe this round is really unfair due to the comment, but no round will be such unfair in the future.
feel sad for delaying today's contest :'(
I'm still in the celebration of being specialist due to this contest :D, but here, you talk about making it unrated. I didn't even have the chance to read F in the contest.
I can confirm in one of the previous rounds I hosted, a problem, which is in a plan to go live, has been rescinded only in the last week because a tester found a similar problem somewhere else publicly. That indicates the setters & testers team always try their best in every round to make the contest as original as possible. Things like this happen, because we're human, and humans can't remember everything!
Well, I am with you with the point that the setters and testers always try their best. All the efforts working for months in preparing the rounds don't deserve all the hate you guys give them just because of a meager coincidence. This criticizes and demotivates the authors and may cause the lack of authors interest in the making the future contests. But you should try to understand that the participants should get all their rights too. Imagine a person solved ABC and is advancing forwards to solve more problems. Seeing the solvers of F more than the solvers of D would force him to contribute his time on solving F which is eventually wrong and unfair. Making the round unrated never meant that the authors were bad or the testers didn't test well, what it just meant is that there was some flaw in the contest which nobody could spot out during the production and this doesn't really seems like a crime to me though. Codeforces is one of the best competitive programming websites available and I would really expect that at least it never prioritize some particular being but should see the scenario from everyone's point of view.
And here is the innocent me trying hard to solve problem F thinking it to be some easy/tricky problem as most of my friends were able to do it. Tired and bored, I was aimlessly browsing the pages just to see this! :(
I don't think unrated is worthless. Everyone can learn a lot from it and improve themselves, but rated is unfair to those who are honest.
What do we participate in the competition for? It is nothing more than to increase experience and improve strength through contest. So when something unexpected happens, it is not an appropriate choice to blindly condemn the author who brought us the contest.
Although this may affect the fairness of the contest, the good thing is that we also achieved the goal of participating in the contest.
Dear Mr. Mirzayanov:
You should be reminded that the innocence of the problem composer and the unintentional mistake of the question testers and reviewer cannot be used as a sophistical excuse to introduce unfairness into the highly competitive environment of CodeForces. The intentions to make the decision to unrate a certain competition, an intention highly intuitive and reasonable, is to prevent unfair results to be given to participants. You know well that competitors who did (or even just viewed) the coincided question will certainly gain an unfair advantage in this competition, which will cause their rating to be unable to represent their true levels of ability. You, as an introducer of this rating system, certainly does not want this to happen.
You mentioned such decisions could not be possibly made in high-tier competitions like the ICPC. However, if one question of it is revealed, prior to the commencement of the competition, to an indeterminant subset of the participants, and many among these have found the solution in advance, wouldn't the board implement measures to prevent the question from being normally placed in the competition? Wouldn't the incident be brewed into a scandal if they have not done so? This is now the case for this very round on CodeForces. Given you are still a highly venerated character and beloved community member amongst us CodeForces users, this 'clarification' greatly perplexed and disappointed us. We sincerely hope that a healthy coding environment can be maintained, which must require the moderators and coordinators uphold the principles of justice and fair-play.
Yours,
A Codeforces user who came from Luogu, believes that Codeforces is more competitive and academic, and hopes to continue to believe so.
Imagine participates a ICPC.You find that there's a file on everyone's Desktop and it tells solution to several problems.But ten minutes later judges comes, deleted all of them, and saying that's just a mistake.
So, do the race makes sense, and should it be seen as a fair one?
So, how good other problems are, or what leads to this error have to do with fairness?
But 765F is well-known, this makes many people who have seen the old question but can't do it better than those who have not seen it, it's really unfair.
I think it's a matter of attitude instead of fairness.
I'd rather not base this on whether an identical problem exists, since it likely will as programming competitions advance (see quote), but how identical.
Are there large chunks that can be found verbatim by copypasting into google? Non-trivially identical samples? Yes, that's bad and could be treated as plagiarism, but could also be a reason to unrate a round even if you're not sure enough to accuse an author. It's a grey area.
Can you find out that those problems are identical once you understood both? Then you have to actually know both problems, with a decent chance that you tried to solve the older one before, which isn't even bad for the competition.
Is the new problem generic enough that you can find the older one just through basic understanding and keywords? A bit sloppy on the author's part, but there are tons of generic meh problems and stuff that can be found online. It's up to problem coordination/testing to prevent that regardless of extra details, and definitely not a reason to punish the author. Round could be unrated if e.g. 1000 people solve a idea-wise hard problem through stack overflow.
In the end we all use other ideas to form our own, so reinvented problems will arise more and more, but they just need to appear different. I wouldn't base decision to unrate purely on plagiarism, but how hard it damages the competition.
I insist that in such cases, no recriminations are acceptable on those who prepared the round for you.
I agree that no one should be blamed, but that is a completely different matter than making contests rated or not. Making a round unrated doesn't mean that the ones who prepared the round is blamed. There are times when Codeforces is attacked by DDOS and the round goes unrated, which is frustrating. But this brings zero recriminations on ones who prepared the round.
Support Mike and Codeforces with no conditions!
Mike is not infallible...
One of the bigger issues was the fact that those stupid comments talking about the repeated problem were left there for a long period of time, leading to many people copy-pasting the solution. CF should prevent comment/blog posting during rated contests. Clearly this will not happen frequently and If you can't wait for 2 hours to post then you have to work on a virtue called "patience".
I don't think this will solve the problem in any way. If the contest with coinciding problems will stay rated, then people who know the problem will always gain an unfair advantage and gain rating. There are online competitive programming discussion groups in the size of thousands, and word will almost inevitably spread out.
Also, It will be very obvious for someone who look at the scoreboard and see instant solves from other contestants.
lmao
Amazing...Maybe I'm wrong initially.
It's an announcement,not a debate.Right?
so fucking decisions