### MikeMirzayanov's blog

By MikeMirzayanov, 5 years ago, translation, ,

With the help of some experienced and respected members of the community (thanks!) there was formulated a rule that allows a third party code to be used under certain conditions. Please read carefully the text.

The following text will go as part of a renewed competition rules. The closest contest will be held already on the updated rules. Thus, there are about two days for further details, if something is unclear.

Solutions and test generators can only use source code completely written by you, with the following two exceptions:

1. the code was written and published/distributed before the start of the round,
2. the code is generated using tools that were written and published/distributed before the start of the round.

Any usage of third-party code should not violate the right holder’s license or copyright. Remember that published code is not always free to use! At the request of the right holder, any code that violates the license or copyright may be considered as violating the rules.

All the changes in the code from exceptions 1) and/or 2) must be made solely by you.

If there are any doubts about the time of publication, possible collaboration etc., a participant will have to prove his/her complete innocence by presenting compelling and satisfactory evidence.

Currently, the only reliable proof is the presence of code on the Internet and the presence of the used edition in the cache of well-known search engines.

For example, this rule accepts the use of the code from the website http://e-maxx.ru/ if the code was written and published/distributed before the start of the round. With the help of search engine caches, it can be easily shown that such code doesn't violate the rules. Similarly, it is permissible to use the code from a book/article that was published before the contest. On the other hand, using team reference code (for example, prepared for ACM-ICPC World Finals) is not allowed if there is no reliable and objective way to prove that the code was written before the contest.

This rule doesn't loosen the rules about prohibiting of communication, discussion, or any other form of communication between the contestants on any topics about the problems during the round.

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 » 5 years ago, # | ← Rev. 2 →   +49 Sorry if this is already answered in the text above, I'm not quite sure.In a number of contest websites (including TopCoder and here on Codeforces), after a contest finishes, the source code for each submission is viewable by any member. Is this considered "published/distributed" code? (e.g. does this rule mean that all contestants can use past submissions of every other contestant?)
•  » » 5 years ago, # ^ |   0 Same question for code snippets published on codeforces.com/blog/
•  » » 5 years ago, # ^ |   -11 Generally speaking, no, authors do not have obligation to release their code into public domain, they only provide unexclusive license for TopCoder
 » 18 months ago, # |   -14 Currently, the only reliable proof is the presence of code on the Internet and the presence of the used edition in the cache of well-known search engines. Do I understand it right? Presence in cache of well-known search engines is mandatory for a proof to be considered reliable, isn't it?What about the Wayback Machine (archive.org)?Is it reliable enough?
•  » » 9 months ago, # ^ | ← Rev. 2 →   -31 It is not polite (and does not serve well to the community) to downvote a comment without any useful reply.
•  » » » 9 months ago, # ^ |   0 As we can see, anonymity of the voting system encourages coward and irresponsible behaviour of the voters.
•  » » » » 9 months ago, # ^ |   +16 What exactly is cowardly about downvoting you?
•  » » » » » 9 months ago, # ^ | ← Rev. 2 →   -23 Downvoting with explanation is supportive and responsible (but yes, it is risky because your explanation comment can be downvoted itself).Downvoting with no useful explanation is just harming another person's contribution score without taking any responsibility or risks for that.That's why I call the latter behaviour coward and irresponsible.
•  » » » » » » 9 months ago, # ^ |   +6 Okay so this is just arguing for the sake of it, but... Contribution score doesn't matter. "Coward" means one is afraid to take a risk. While indeed downvoting doesn't take any risks, people don't downvote comments because they are afraid of taking risks. People downvote comments because they are wrong, offensive or just plain garbage.
•  » » » » » » » 9 months ago, # ^ | ← Rev. 2 →   +3 Then why not to explain the reason of downvoting in a couple of words?Otherwise, how an author (of a downvoted message) is expected to learn what exactly is "wrong, offensive or [inappropriate]" about his/her comments and why it is considered wrong?(I think the practice of explained downvotes would significantly decrease the total number of "wrong, offensive or just plain garbage" comments because their authors had a chance to learn community rules faster: what is considered bad in this specific community, and why.)I understand that there are obvious cases (such as offensive comments) where explanation is not needed. But in this specific case it was not obvious (and it is still not obvious). Not for me, at least.
•  » » » » » » » 9 months ago, # ^ |   0 "Coward" means one is afraid to take a risk. Agree.And this actually does not cover ones who are not afraid to take the risks but just too lazy busy to explain themselves. On the other hand, I would not call such behaviour responsible (giving to the community is important, just taking from it is not good).
•  » » » » » » 5 months ago, # ^ |   +14 Stackoverflow tried to solve this problem by removing 1 point from your reputation when you downvote something.
•  » » » » » 9 months ago, # ^ |   -10 (A bit more detailed answer. Back to the original issue.)A bad thing -- as I see it -- is that I was left alone with my downvoted comment and without important information.Specifically, I still have no idea why the original comment was downvoted.I do not have information, neither about what exactly was bad about that my comment, nor about who downvoted it (so that I could ask them personally).How should I learn from my mistakes in such situation if I do not understand what exactly my mistake was?In my opinion, sharing information which allows other members to learn is a crucial thing for a community.
•  » » » » » » 3 weeks ago, # ^ |   +8 I was also very confused by your comment downvotes, i undestand the way you fell, and really appreciatte the fact that you are not giving up and blaiming youself. People downvote maybe just to feel better and harm others, idk.I see many guys explaining their solution to problems that are not in editorial and require some advanced knowldge getting downvoted. That's the way things are, nothing to do about that. MAYBE I WILL GET DOWNVOTED TOO,tring to keep your side.
 » 9 months ago, # |   +1 Solution to problem Codeforces round 447 Div.2 question A. QAQ was already available on the internet, well before the contest.Please visit source — http://www.geeksforgeeks.org/find-number-times-string-occurs-given-string/ to confirm. Hence I don't think people should be penalised if their code matches with someone...as they both referred the same source....codeforces please see into it !
•  » » 9 months ago, # ^ |   -25 I Agree.I am using Ideone keeping it secret since 15 contests.It has not done yet.don't skip my contest.plzz consider my case...!! MikeMirzayanov
 » 9 months ago, # |   -13 delete2, coutinho, OutSpace, blindspot — this is 4 photo machines. You will can’t better, lol
 » 8 months ago, # |   +4 Hello Everyone, This morning I got a message from system that my submission http://codeforces.com/contest/911/submission/33725640 during the Educational Codeforces Round 35, has been found significantly similar to http://codeforces.com/contest/911/submission/33725051 and my account my get blocked due to this.Both of the submissions were made my me for Question C, and i was thinking that the earlier one would be ignored as we have in any normal Round. I request the community to help me out here as I don't know whom should I contact about this.
•  » » 8 months ago, # ^ |   +2 For sure it is a technical mistake and it will be fixed today. Sorry about it....And Happy New Year!
•  » » » 8 months ago, # ^ |   0 Thanks a ton for everything sir :)
 » 7 months ago, # | ← Rev. 2 →   -9 :(
•  » » 7 months ago, # ^ |   +12 I also made such stupid mistake. Sure, it is so awkward.
 » 7 months ago, # | ← Rev. 2 →   -20 sir, coder_tuntun is my another account . and in today's contest #459 i submitted same solution for problem b , and i was not aware of the fact that we cannot submit same solution from two different accounts. this was unintentionally ...i feel really really sorry for such a big mistake from my side.i will take care of all the rules from next time onwards. please forgive me this time. sir please update my rating i solved both A and B.
•  » » 7 months ago, # ^ |   -8 Sir, in this case why you update rating of my coder_tuntun account and cancelled on the tintin account. If you want to cancel then please cancel it on coder_tuntun account. And sir please reply.thank you.
 » 7 months ago, # | ← Rev. 3 →   -8 Solution to problem Codeforces Round #459 Div.2 question A. Eleven was already available on the internet and it is well before the contest. Please visit source — https://www.geeksforgeeks.org/check-number-fibonacci-number/ to confirm. I got a message from the System and it stated that My code matches with someone else's code . And my code got skipped.
 » 7 months ago, # | ← Rev. 2 →   0 Hello Everyone, This morning I got a message from system that my submission for 918A khyati.agarwalss/34669006 during the Contest, has been found significantly similar to someone else's solution and a warning that my account may get blocked due to this. I wrote a very basic solution for that problem which was a short cut method, and it may possibly match with someone else's because no particular algorithm was applied in it and I used a saved syntax of jdoodle/c++. I request the community to help me out and make my solutions valid for the round 918 Div.2.
 » 7 months ago, # | ← Rev. 2 →   -8 zhongyin is my other account.I wasn't aware of the rules. So I submitted same code in both accounts in Codeforces Round #459 (Div. 2) contest. I am really sorry for my actions.
 » 7 months ago, # |   -8 zhongyin is my other account.I wasn't aware of the rules. So I submitted same code in both accounts in Codeforces Round #459 (Div. 2) contest. I am really sorry for my actions.
 » 7 months ago, # |   -12 This is my another id that was opened with another browser... unfortunately I submitted Codeforces Round #460 (Div. 2) B from #RAKIB_CSE_14#..... Then i submit from #Logical_Error# account.
 » 7 months ago, # |   -8 RAKIB_CSE_14 is my another id that was opened with another browser... unfortunately I submitted Codeforces Round #460 (Div. 2) B from RAKIB_CSE_14..... Then i submit from this account..
 » 7 months ago, # |   0 Please clarify the message that is sent to users. I don't know where to "write a comment to post about the round with all the details". If this is the right place, please re-evaluate my solution for contest 919. The system claims neutron-byte/34741180 is similar to czommerfelds/34745389. The solution is very simple so it is no surprise it would be similar. Also the first result on Google for "c++ sum of digits" yields the same function http://www.sanfoundry.com/cpp-program-display-sum-of-digits/. Thank you. Best, Christian
 » 6 months ago, # |   +1 hello codeforces, i had a message after Educational Codeforces Round 37(Rated for Div. 2) .which says that Your solution 34846770 for the problem 920A significantly coincides with solutions oneplus3/34846646, codinghunter/34846770 .i want to say that both of the accounts(oneplus3 and codinghunter) were mine and i don't know the rules of submissions . But i promise that the soutions of both accounts is completely mine, and i won't make this mistake again.Don't block my accounts
 » 6 months ago, # |   0 "Attention!Your solution 35396581 for the problem 939A significantly coincides with solutions Mushfikur_Rahman/35392093, RezaSi/35396581. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details. More information can be found at http://codeforces.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties."i dont know him and not published my code any where :/ ... that's simple problem and may be many user have same solution for A problem in contest :/
 » 6 months ago, # | ← Rev. 2 →   0 I received a message from CodeForces after round# 464 that my solutions for A,B and D have been plagiarised. The solution to D was DSU and code was available on HackerEarth link for D's code. Problems A and B were trivial, I think because of similar template the solutions have been caught. The template which I use is really common. The codes for A and B were of <10 lines and hence the similarity. Kindly look into the matter.The variable names which I use are really common amongst the programmers hence the similarity.
 » 6 months ago, # |   0 OK I do not know how this happened, and I was sure that I do not know this person at all. And when I entered his account, it turned out that he had been registered for a very short time, so how can I know him? I swear I did not take this solution from any Someone, whatever. Thank you
•  » » 6 months ago, # ^ |   0 Please I want my rank ...because I do nothing
 » 6 months ago, # |   0 Hi Mr.Mike! I'm Amir and today i passed the contest with my submissions but your system and your employees i don't know, said that i submit a copy code for my self. i have a question: If i have two different accounts and i want to participate in both of them, i can't do this?!?!I'll thank you if answer my questions, rapidly! Thanks again!
•  » » 6 months ago, # ^ |   +1 Having more than one account is prohibited by the rules AFAIK.
 » 6 months ago, # |   0 i just wanna to ask if 2 accounts belong to 1 person and he did the contest with 2 accounts at the same time. Is it violation?
•  » » 6 months ago, # ^ |   0 I wanna to know that same as you !
 » 6 months ago, # |   0 I'm sorry to have happened such a thing, and I won't do it again. I had a fluke in the game.
 » 6 months ago, # |   -12 I don't know how it happened I have used logic which I have seen in the internet
 » 5 months ago, # | ← Rev. 3 →   -28 Today I got a message after Educational Codeforces Round 39 (Rated for Div. 2) that solution 36000027 for the problem 946A significantly coincides with solutions yashwant750/35999435, yash750/36000027. I want to tell that both of are my accounts and I didn't had any idea that 2 accounts are prohibited,so I am really sorry about it and I assure you that it wont happen in future and I won't be using the other ID from now on.
 » 5 months ago, # | ← Rev. 5 →   -31 Do you know why my answer is similar? Because the account is mine.I submit my code on my account and i submit it with this account. Whatever,i am sorry for this thing happened.I promise it won't happen again.
 » 5 months ago, # | ← Rev. 2 →   -28 Sorry about that...But both of these accounts are actually mine. Please consider my submission and give me my rank back. And this will never happen again in future.
 » 5 months ago, # |   0 In Codeforces Round #469 (Div. 2),when I was doing problem C,I communicate with another friend. He sent me his error code. I submitted it after correcting it. He also submitted it after correcting it.I'm sorry to have happened such a thing, and I won't do it again.
 » 5 months ago, # |   -23 Attention!Your solution 36167133 for the problem 948A significantly coincides with solutions avyaktg98/36161438, kogorou/36167133. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details. More information can be found at http://codeforces.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties.This is a brute force solution and there was a similar problem "Palindromic Supersequence". Also if the members of the same team gets the same solution I recommend giving time to the involved participants to make changes in their code as the solutions are constructed while sitting in the same room. This type of instance is highly regretted and will be careful for the next time.
•  » » 5 months ago, # ^ |   +3 The solutions are not similar, they are completely the same. No one can believe in such coincidences.
•  » » » 5 months ago, # ^ |   0 Nice memessame code + same compiler
•  » » » » 5 months ago, # ^ |   0 That's because of Undefined Behaviour. You should erase by iterator, not by value (because in multiset you will delete all such values and iterator iter can become invalid)
•  » » » » » 5 months ago, # ^ |   0 Thank you for clarification
 » 5 months ago, # |   -20 Why??
 » 5 months ago, # |   -15 Why did my solution got skipped?
 » 4 months ago, # |   +19 Attention!Your solution 37167311 for the problem 962E significantly coincides with solutions cuom0405/37165015, flibia/37167311, anno/37167796, pepi_angelov/37167900. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details. More information can be found at http://codeforces.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties.I used the official solution written in the Goodbye 2017 Editorial: https://www.dropbox.com/sh/i9cxj44tvv5pqvn/AAB1_2Q0XKvKiOA1ukvcNIuUa/F?dl=0&preview=F.cppSolutions and test generators can only use source code completely written by you, with the following two exceptions:the code was written and published/distributed before the start of the round, the code is generated using tools that were written and published/distributed before the start of the round.I used a code that was written and published / distributed before the start of the round.
•  » » 4 months ago, # ^ | ← Rev. 2 →   +7 The exact same thing happened with me !!I copied Petr's code, I thought it would be better than the editorial anyway xDThis is my submission:http://codeforces.com/contest/962/submission/37169973This is Petr's submission on the problem from Goodbye 2017 round:http://codeforces.com/contest/908/submission/33777962This code was written before the start of the round. Apparently someone else copied the same code and I was charged with it being a violation?? I don't think that's fair.
•  » » 4 months ago, # ^ |   +8 I just saw that somebody else has written about our common problem, tell me if something changes for you.
 » 4 months ago, # |   0 Sorry, for being irresponsible. Yesterday in the "Educational Codeforces Round 42 (Rated for Div. 2)" I unintentionally used ideone as my system compiler wasn't working fine.I forgot to change the visiblity settings of ideone and someone intentionally misused my code. I would take care in future to not repeat this. my ideone code link during the contest is https://ideone.com/8vObjQ I saw the users profile with whom my code coincided(as said by you) ,his every solutions had been skipped which means he has a habit of copying. So i am innocent.
 » 4 months ago, # |   +8 Attention! Your solution 37167900 for the problem 962E significantly coincides with solutions cuom0405/37165015, flibia/37167311, anno/37167796, pepi_angelov/37167900. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details. More information can be found athttp://codeforces.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties.This is the problem I used as my source (and probably the others): http://codeforces.com/contest/908/problem/F 962E is just the same problem as 908F.
•  » » 4 months ago, # ^ |   +8 https://www.dropbox.com/sh/i9cxj44tvv5pqvn/AAB1_2Q0XKvKiOA1ukvcNIuUa/F?dl=0&preview=F.cpp And this is the source code
 » 4 months ago, # |   +13 FOR EDUCATIONAL ROUND: 42 ( The latest one)I received a mail about violating the rules of the contest, by copying the code. But I have conclusive evidence that I had taken the code from a AC code of another problem, 908F. If u want I can link the solution here, from which I took the code. However, it was present BEFORE this contest began. So I am not sure how this can be a violation of the rules. It's the setters fault that the problem was exactly the same.My solution : http://codeforces.com/contest/962/submission/37168611 The code I took it from: http://codeforces.com/contest/908/submission/33800403I too had a AC code to this problem:908F (http://codeforces.com/contest/908/submission/33824171) But that got some error, so I decided to take another code. Please nullify the claim that I collaborated with someone else during the contest. It is pure coincidence that they took the same code.
 » 4 months ago, # |   -18 sir they both are my account and i didn't know about the submission policies .... please don't block or penalty my account ...i assure you this will not happen again
 » 4 months ago, # |   0 Sorry, I don't know the code can't be discussed, this is the result I discussed with him.
 » 3 months ago, # |   -12 hello codeforces, i had a message after Codeforces Round #481 (Div. 3) which says that your solution 38168041 for the problem 978B significantly coincides with solutions mithun_rahman/38167870, codefresher/38168041.i want to say that this is just a coincidence.I had evidence to prove it.But for some reason i lost it.But i want to say that this code is mine.I request you to check the code for the contest and please make it valid.I also thank you to know the rules.and please don't block my account...→ Reply
 » 3 months ago, # |   -12 My solution 38295464 for the problem 984D significantly coincides with solutions yqdjl4/38292975, xiaowuga/38295464. I think the idea of this problem is relatively simple, the code is short, the possibility of the code similar is very great, I see the idea of the code is almost the same, this question is I think independently, I hope to restore my ranking,
•  » » 3 months ago, # ^ |   -12 This question is not difficult, It doesn't need any algorithm. This problem needs to be preprocessed.I do not have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition.But I stayed up all night playing this game and seriously ponder every question. I don't want to be skipped this contest.please!!!!!
 » 3 months ago, # |   0 I did this question before this competition .I was having the solution file so i just copied my solution it. This may be the coincidence he got the same code from the website. i don't remember the name of educational website.
 » 3 months ago, # |   0 hello.. I just got the message.. Attention!Your solution 38659699 for the problem 981A significantly coincides with solutions i_wanna_work_at_google/38659167, tushar_2658/38659699. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details. More information can be found at http://codeforces.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties.I dont know this guy.. maybe the solutions coincided.. requesting for a recheck.. and I didnt get any solutions from any source or other stuffs
•  » » 3 months ago, # ^ |   0 Note that unintentional leakage is also a violation. Solutions are the same. By default some online IDE (like Ideone.com) publish codes. BTW I find it extremely weird or even dangerous. Be careful with them. Also prefer to use HTTPS in future and change passwords. Good luck.