MikeMirzayanov's blog

By MikeMirzayanov, 8 months ago, translation, In English,

Hello, Codeforces!

As many of you I'm not really satisfied how the round 497 has ran. KAN is not working on Codeforces this month, he is out of the city. It was a first round coordinated by arsijo. I liked his enthusiasm and work he did. But it happened, it wasn't an example of a well-prepared round.

The main issues are as follows:

  • The problem statement in the problem A wasn't clear enough (actually, it didn't contain any mistakes, just wasn't easy to understand).
  • The improper example to illustrate the problem B (no mistake here, but it has confused some users).
  • I really didn't like the statement of the problem D2D/D1B. I agree it wasn't good. Again it didn't contain any mistakes, but it was hard to understand it quickly. Also I did the incorrect announcement (but it was fixed quickly).
  • The incorrect behavior of the interactor in the problem D2E/D1C (Time Limit Exceeded/Idleness Limit Exceeded on too many queries instead of Wrong Answer).
  • The huge gap in the difficulty between the D2C and the D2D.

Right now, I'm really do not sure, should the round be a rated or not. What is your opinion about it? The current idea of the writers and the coordinator to make it unrated for whose, who got incorrect verdict on D2E/D1C.

Anyway, I'd like to say “thanks” to the problem writers, testers and the coordinator arsijo. They really tried to make a good round. I hope to see more rounds from Skyglow and coordinated by arsijo. I'm sure they made proper conclusions from the round.

Thanks, MikeMirzayanov

UPD: Thank you for sharing your opinion. The round is rated.

Tags 497
 
 
 
 
  • Vote: I like it  
  • +270
  • Vote: I do not like it  

»
8 months ago, # |
  Vote: I like it +277 Vote: I do not like it

I didn't get any incorrect verdicts in div1C, so I see literally no reasons to make the round unrated.

And I don't think that round is bad. div1ABC are OK. Cannot say anything about div1DE since I don't know how to solve them. E looks really interesting, D — less so. Huge gap in difficulty and overall difficulty is not great and I would prefer easier BC, but it is not the reason to say that the round was bad.

  • »
    »
    8 months ago, # ^ |
      Vote: I like it +35 Vote: I do not like it

    Oh, no announcement for 10 minutes extension isn't good. But still not a bad round :)

    • »
      »
      »
      8 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      There was an announcement of extension in div2 at least.

      • »
        »
        »
        »
        8 months ago, # ^ |
          Vote: I like it +39 Vote: I do not like it

        Well, in div1 there wasn't.

    • »
      »
      »
      8 months ago, # ^ |
        Vote: I like it +14 Vote: I do not like it

      What announcement? The round was extended? I didn't know.

  • »
    »
    8 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The fact that D,E div1 is unsolvable by you is already a bad sign. I still don't think it should be unrated.

    • »
      »
      »
      8 months ago, # ^ |
        Vote: I like it +16 Vote: I do not like it

      First, that's not true. I'm just one man, even if I'm pretty good at CP. There are topics which I don't like, there are topics in which I'm bad. After all, it can be that I didn't come up with some easy observation. There are a lot of cases when strong guys can't solve the problem which is solved by hundreds of people.

      And second, I don't think that they are unsolvable. E is very hard even after I read the editorial, but both solutions for D from editorial look doable (in a sense that I could come up with that solution if I had more experience with that kind of problems and/or more luck).

»
8 months ago, # |
Rev. 6   Vote: I like it +190 Vote: I do not like it

Unrated status is mostly for round with technical issues, such as mistakes in problem statement, mistakes in author's solution or long queue. But here I see no reason to do that (except div1C ofcourse). Bad (from some points of view) round dose not mean it should be unrated. Also have seen worse rounds with rated status.

»
8 months ago, # |
  Vote: I like it +103 Vote: I do not like it

I don't think it should be unrated, it had no technical problems and no one got hurt from the problems you said

I agree that there was a huge gap between C/D div2 but it happened before a lot of times and the round still was rated

so i hope it will be rated

»
8 months ago, # |
  Vote: I like it +60 Vote: I do not like it

We also had rated contests with big queue during them before. So make contest unrated only because of bad problemset? Don`t think so

»
8 months ago, # |
Rev. 2   Vote: I like it +51 Vote: I do not like it

I think, it should be rated.

»
8 months ago, # |
  Vote: I like it +44 Vote: I do not like it

I already asked about this in contest thread, but it seems that it has gone unnoticed. Why ML in custom invocation is just  ≈ 500 megabytes? There are problems with higher ML out here, for example Div1 D in this contest. It makes TL and ML testing kinda difficult.

  • »
    »
    8 months ago, # ^ |
      Vote: I like it +25 Vote: I do not like it

    There is such a constrait in the testing tool, but we needed to raise the ML, because several testers got it.

    • »
      »
      »
      8 months ago, # ^ |
        Vote: I like it +31 Vote: I do not like it

      Is it possible to raise ML in custom invocation at least during contests where ML is bigger than usual (in future, of course)? The same for TL also (TL in custom invocation is 10 seconds, if I recall correctly, but there were problems on CF with 15 seconds TL).

»
8 months ago, # |
  Vote: I like it +28 Vote: I do not like it

Rated

»
8 months ago, # |
  Vote: I like it -17 Vote: I do not like it

I think that making this round unrated is unfair for many users , so making this round semi rated can be a solution.

»
8 months ago, # |
  Vote: I like it +29 Vote: I do not like it

Must be rated. I solved 3 problems. Btw not face any problems with the statement.

»
8 months ago, # |
  Vote: I like it +16 Vote: I do not like it

I think, it should be rated

»
8 months ago, # |
  Vote: I like it +37 Vote: I do not like it

i think this round is not bad, its just hackmore round, though problems were difficult to undersrand due to confusing statements... for div2 theres no reason to make it unrated.. i support sir Um_nik

»
8 months ago, # |
  Vote: I like it +37 Vote: I do not like it

Rated is OK.No need to make this round unrated just because of the difficulty gap.In fact, I think these problems are very interesting.

»
8 months ago, # |
  Vote: I like it +35 Vote: I do not like it

I think it should be kept rated. There were no technical issues. Making it unrated just because of under-quality problem statements in unfair.

»
8 months ago, # |
  Vote: I like it +26 Vote: I do not like it

It should be rated, for sure

»
8 months ago, # |
Rev. 2   Vote: I like it +22 Vote: I do not like it

If there were any problems that were not clear then everyone faced the same.It should be rated.

»
8 months ago, # |
Rev. 5   Vote: I like it -17 Vote: I do not like it

I think codeforces created for solve problem and get rate not hack problem and get rate. Isn't it ?

Hack a problem in compare with algorithms is not important.

So, if this round will be unrated better for all users.

Hack is very related to your chance maybe in your room all users submit carefully their codes.

UPD : Most users think this round should be rated so I reverse my idea so now I think this round should be rated :)

  • »
    »
    8 months ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    you cannot hack a solution unless you have understood problem from all sides... its just extra points for your better understanding

    • »
      »
      »
      8 months ago, # ^ |
      Rev. 4   Vote: I like it +9 Vote: I do not like it

      Not always, as I said Hack is very related to your chance maybe in your room all users submit carefully their codes.

      UPD : Most users think this round should be rated so I reverse my idea so now I think this round should be rated :)

    • »
      »
      »
      8 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Not really in most cases it's about just finding 1 edge case not covered in pretests and being lucky enough that your roommates make a mistake and you open it first.

»
8 months ago, # |
  Vote: I like it +13 Vote: I do not like it

I think it should be rated.

»
8 months ago, # |
Rev. 2   Vote: I like it +24 Vote: I do not like it

In my opinion, problem statements were pretty clear (I have read them quite fast only once and understood everything correctly).

Don't see real problem with wrong verdicts. I mean you still get verdict "Your solution is wrong". If somebody tried to fix his problem using these verdicts, then as I think it's kinda restricted (abusing test system or something like that).

Huge gap in difficulty is not a reason at all. There were lots of rounds with even bigger gaps.

IMHO, should be rated.

»
8 months ago, # |
  Vote: I like it +53 Vote: I do not like it

Agree to make it rated, even though I will lose some ratings

»
8 months ago, # |
  Vote: I like it +20 Vote: I do not like it

I think the round should be rated.

»
8 months ago, # |
  Vote: I like it +5 Vote: I do not like it

I think the problem statements were not that hard to make the round unrated. Although sometimes the problem statements should be tough I guess so!

»
8 months ago, # |
  Vote: I like it +12 Vote: I do not like it

It should be rated.The description of the topic is very clear.Many people read quicly and correctly,right?

»
8 months ago, # |
Rev. 2   Vote: I like it +11 Vote: I do not like it

The round should be rated. Though there were quite a few announcements, but there was no mistake in the authors solution or in the statement. Moreover, the round was extended by 10 minutes.

»
8 months ago, # |
  Vote: I like it +10 Vote: I do not like it

there was huge gap between problems, but it should be rated

»
8 months ago, # |
  Vote: I like it +25 Vote: I do not like it

Please, make it rated.

»
8 months ago, # |
  Vote: I like it -68 Vote: I do not like it

Although the work done by testers, problem setters and coordinators is appreciable but still, the contest should be declared unrated. Reasons: Lots of announcements, wrong announcements, corrected announcements, wrong or unclear problem statements and the ratio of people solving div2D/div2c clearly demonstrate that the contest was hugely unbalanced. The reds and oranges may be experienced enough to get the tougher problems right, but the majority of the people, I guess were affected by all the things going simultaneously and the uneven difficulty of problem distribution. Even if the round goes rated, it's not going to affect me much, but still considering the welfare of the majority of cf community, it would be in best interest of everybody to declare it unrated.

  • »
    »
    8 months ago, # ^ |
    Rev. 2   Vote: I like it +1 Vote: I do not like it

    O_o

  • »
    »
    8 months ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    In the past, neither difficulty spikes in the problems nor unclear statements (and D1B has been clarified in time) have caused a round to be unrated. By this logic, this round should be rated.

    • »
      »
      »
      8 months ago, # ^ |
        Vote: I like it +1 Vote: I do not like it

      Cool, you guys can stop downvoting.

»
8 months ago, # |
  Vote: I like it +19 Vote: I do not like it

Those issues seem like pretty minor things, keep it rated IMO

»
8 months ago, # |
  Vote: I like it +14 Vote: I do not like it

I think nobody faced any problems with the statement of A and the unclear example in B statement was solved by an announcement and it happened so many times in contests that ended up being rated. I think also that gaps between problems occur sometimes and honestly it is annoying but enough to make the round unrated. After all, I think the round should be rated or at least for those who didn't encounter problems with D2 E (I didn't even read it so I don't know what the problems were).

»
8 months ago, # |
  Vote: I like it +8 Vote: I do not like it

It Should Be Rated....All Faced The Same Problems and Same Issues But It was Small Issues And Solved and After That Round extended with 10 minutes

»
8 months ago, # |
Rev. 2   Vote: I like it -8 Vote: I do not like it

Must be rated sorry

»
8 months ago, # |
  Vote: I like it +7 Vote: I do not like it

As there were no mistakes, so the round should be rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Rated

»
8 months ago, # |
Rev. 7   Vote: I like it +5 Vote: I do not like it

Rated I think, saying this although I may be biased now :)

»
8 months ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

It should be rated because, in the past, these kinds of issues (which are minor) have not caused a round be unrated, so in this case it shouldn't, either. Besides, in D1C the authors already said that you would get Idleness Limit Exceeded instead of Wrong Answer, so no issue here either.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Rated! It was a cool round, really hard D2C/E but it happens

»
8 months ago, # |
  Vote: I like it -43 Vote: I do not like it

Div1 rounds should be eliminated. Rounds should be combined like at csacademy.

»
8 months ago, # |
  Vote: I like it -11 Vote: I do not like it

I think the round should be unrated, as far as I know, no one even solved d from div 2, problems A B C were just type racing problems, and that's enough to make the round unrated, what is the point of rating such contest if all problems solved been almost solved by all contestants, that's totally unfair for many contestants, if were there just one problem only one on which we could tell who're better than another, only then this round should be rated,unless codeforces round meant for testing our hands not our brains

»
8 months ago, # |
  Vote: I like it +16 Vote: I do not like it

rated.I don't want to be told "unrated" at 2:00 in the morning,and there wasn't such a big problem in this round.

»
8 months ago, # |
  Vote: I like it +43 Vote: I do not like it

I didn't participate in this round but all these issues seem really like minor ones. Compare this to round 485 which was a complete mess and which was rated.

  • »
    »
    8 months ago, # ^ |
      Vote: I like it +34 Vote: I do not like it

    If a bad decision were made to make round 485 rated,that doesn't justify more bad decisions

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

I feel to make it rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Is it rated?

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Though there are some issues, I prefer to make the round rated because there are not any serious problems(such as wrong statement,wrong testdatas and so on).

Of course,maybe semi-rated is also ok for everyone.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I think, it should be rated

»
8 months ago, # |
  Vote: I like it +2 Vote: I do not like it

I think contest should be rated for Div2, because a little of people send solving Div2E.

»
8 months ago, # |
Rev. 5   Vote: I like it -57 Vote: I do not like it

I didn't participate in this contest(I was 5 minutes late and decided not to participate :(, now I regret), but I think It should be rated. Problems with statements made more difficult solving tasks. But All participants were in equal(bad) conditions. And in my opinion technical problems with problem div2E/div1C and no announcement for 10 minutes extension aren't enough to make it unrated. Because we have had rated contests with tougher issues(that huge queue).

  • »
    »
    8 months ago, # ^ |
    Rev. 2   Vote: I like it -38 Vote: I do not like it

    At current time this comments vote is 0, but I have got -5 contribution. I think sirShokoladina has called his red/yellow friends to downvote my comment :D(just a joke)

  • »
    »
    8 months ago, # ^ |
      Vote: I like it +14 Vote: I do not like it

    You're exaggerating it. I won't argue as to whether it was a bad contest, but accusing that they only tried to advertise their band is really mean. OK, the difficulty gap was bad, but that doesn't mean the setters didn't try their best. Please don't underestimate the effort it takes to prepare a round. On the bright side, the problems were rather interesting, so kudos to the setters.

    On D1C/D2E, at least 116 coders from the first division read it, and only 9 solved it. I wouldn't say it's easy.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Absolutely must be rated...

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

I would rather have the round declared unrated. Too many issues, as outlined in the original post. English language statements were particularly of concern for me as a fresh Div1 competitor. I also got a TLE on Div1C, not to mention.

»
8 months ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

I think the round being unrated will be injustice to many users and being rated injustice to those who got Wrong verdict.

** The current idea of the writers and the coordinator to make it unrated for whose, who got incorrect verdict on D2E/D1C**

this idea is good for both

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Rated

»
8 months ago, # |
Rev. 2   Vote: I like it +22 Vote: I do not like it

I think that the round should be rated for people who were affected by the incorrect verdict on D2E/D1C but would get a rating increase. Making the round unrated for those people would amount to punishing them twice. And since few people are in this situation, I don't think it would cause significant rating inflation.

To be clear, I'm mostly saying this because that I am one of those people. :D

»
8 months ago, # |
Rev. 2   Vote: I like it +7 Vote: I do not like it

I failed pretty hard, mainly due to hard to parse statement on C, and I think round 485 should be unrated instead. (That's the one where having feedback mattered a lot, but I waited for my "sorry, MLE!" for 2 hours.)

The statements were unclear, but I'm not sure if it's unrated-tier bad. The gaps in difficulty are completely okay as long as it's not everything that's too hard, there will always be a gap somewhere. Now behaviour of the interactor in div1C... I assumed it's correct behaviour and it took me some 20-30 minutes to figure out my Idleness Limit Exceeded isn't because I'm flushing incorrectly or some dark magic like "you have to read the final 0". What to do with that depends on the scale of how it messed up the contest and how much different it is from expected behaviour. Perhaps unrate people whose contests were clearly messed up if you decide for unrating?

Btw I find it hard to write this comment, the site is hanging when I try to post.

UPD: Seems like a lot of div2 people want it rated :D

»
8 months ago, # |
  Vote: I like it +5 Vote: I do not like it

It should be rated. There were no technical issues and nothing seriously wrong with the problem statements. The only legitimate issue on this list is the last one (the large difficulty gap), which, while it can make the contest less enjoyable, is certainly not cause for it to be unrated.

Declaring rounds unrated simply because people didn't like the problems would seriously hurt the credibility of the codeforces rating system.

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Rated,of course.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I think the round should be RATED__ because of the following reasons:-

There are many contests when there is a difference of difficulty between two consecutive problems. But we never made it unrated before. Maybe the problem statement was too much technical, that's why many people got confused according to me. Otherwise many other ones also submitted them within 5-10 mins. So they were not that much confusing a/c to me.

Secondly, in my experience, Codeforces round was declared unrated in case of technical issues like long queues or some site failure. But in even some of the cases, you made it unrated. Thirdly, as well said Sports Programming is also a game of speed. The faster you solve, the more accurately. The more rating++ you get.

Lastly, there will always be some people who gonna criticise the round, but I think maybe they should be Ignored.

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Rated

»
8 months ago, # |
  Vote: I like it +14 Vote: I do not like it

(DIV 2) Many solved 3 tasks. The two tasks(D,E) were solved by the units. I think it makes no sense to make a round of ratings.

»
8 months ago, # |
  Vote: I like it -19 Vote: I do not like it

Unrate

»
8 months ago, # |
  Vote: I like it +7 Vote: I do not like it

When will we know the final decision?

»
8 months ago, # |
Rev. 3   Vote: I like it +4 Vote: I do not like it

I didn't have a single issue understanding first 4 problems. In problem E, I asked a question to the round coordinators, and they replied me a few seconds later, so everything was fine. There has been a lot of rounds where the difficulty gap was huge, but still that rounds were rated. Also, no technical problems occurred. So, in my opinion, the round should be rated for everyone.

»
8 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Though i faced problem with D2C's example but it should be rated.Div2E was really cool.

»
8 months ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

I'd like to see this round go semi-rated.

»
8 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Rated.

»
8 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Questions were fine. It should be rated.

»
8 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Rated

»
8 months ago, # |
  Vote: I like it +15 Vote: I do not like it

Declaring a round unrated destroys a major external reward for students, and moreover emblazons a scarlet letter on the problemsetter. In cases where it is obvious the round should be unrated, we have no choice but to incur these costs. But when the objections are only minor, there is no reason this should happen.

»
8 months ago, # |
  Vote: I like it +4 Vote: I do not like it

I don't think this round has caused such major issues that it has to be declared unrated. Count my vote in "round should be RATED".

»
8 months ago, # |
Rev. 2   Vote: I like it +33 Vote: I do not like it

I think that the huge gap in the difficulty of any problem set shouldn't be considered an issue.

  1. We are provided with the same problem set. So regardless of the problems' difficulties, it is fair for everyone.
  2. For me, I participate in contests just to challenge myself, so whether there is a huge gap or not, I will be satisfied.
»
8 months ago, # |
  Vote: I like it +4 Vote: I do not like it

Rated. In this round was not big issues.

»
8 months ago, # |
  Vote: I like it +6 Vote: I do not like it

problem statements were definitely not clear for problems B and D ...several people including me lost on problem B,according to me making the round unrated is the wise decision.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I don't think this round should be declared unrated. No doubt there were difficulties in D2D/D2E but most of the people took that as an opportunity to go for hacks. And you cannot discard/neglect the effort one has taken in hacking.

Hence, the round should be RATED.

»
8 months ago, # |
Rev. 2   Vote: I like it +13 Vote: I do not like it

I don't think the issues the round had are major enough to make it unrated, but given that 5/6 div1 participants only solved div1A, and div1A was so trivial as it was, Rating changes caused by this round are ridiculous. For most contestants, their rating change isn't influenced AT ALL by their ability to solve problems, only the speed at which they can solve trivial problems. And not only that, the rating changes caused by something this random be massive.

For example, look at me, and my friend Kuha. He's generally a great competitive programmer, but most of all, he's really fast. Before the contest I had 105 more rating than he did. In this contest, he solved A very fast, in just two minutes, and CF-predictor is saying he will get +30 rating. I solved A in seven minutes, giving me a expected rating change of -76. So after this contest, he will be higher than me in rating.

I think the round should be semi-rated, to still reward those who managed to solve more than just A, and to minimize the random change to the ratings of the 5/6'ths who didn't.

EDIT: Of course, this reasoning doesn't apply to the div2 version of the round, and I do think it should stay rated as normal.

  • »
    »
    8 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    To be fair, there isn't that much difference in rank between people that solved AB and people that solved A in two minutes. So making the round semi-rated just unfairly punishes people that solved AB.

  • »
    »
    8 months ago, # ^ |
    Rev. 2   Vote: I like it +8 Vote: I do not like it

    It's a very strange conclusion. There are a lot of rounds which aren't ideal, so do we need to cancel all of them? I could find places which are regarded unfair and very strange by me in big number of rounds, but, actually, nobody will write rounds if we begin cancel them.

    Actually, I agree this things are very bad. And I hope the coordinators will suggest us rounds with a good differentiation and more number of solvable tasks.

»
8 months ago, # |
  Vote: I like it +4 Vote: I do not like it

Its really strange how pepole care lot about rating instade of solving problems, I usually do rounds for fun/to improve my skills, guys rating is just a number :D

»
8 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Well, there were some problems, but they weren't too severe to make the round unrated. Also, the situation was equal for everybody. So, I think it'd be better to keep it rated.

»
8 months ago, # |
  Vote: I like it +1 Vote: I do not like it

The round should be RATED.

»
8 months ago, # |
Rev. 2   Vote: I like it -7 Vote: I do not like it

rewarding people for solving 3 questions of low difficulty should definitely not be done

»
8 months ago, # |
  Vote: I like it +8 Vote: I do not like it

I think it should be rated!

»
8 months ago, # |
  Vote: I like it +8 Vote: I do not like it

There is no reason to make this round unrated.

»
8 months ago, # |
  Vote: I like it +13 Vote: I do not like it

A difficulty gap and minor inexplicability of statements don't justify making a round unrated.

There were 0 technical issues.

As such I say the round should be rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

This round should be rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

rated

»
8 months ago, # |
  Vote: I like it +2 Vote: I do not like it

In Div2 I found no reason to make it unrated.

»
8 months ago, # |
  Vote: I like it +2 Vote: I do not like it

Since there are no mistakes — I think it must be rated

»
8 months ago, # |
  Vote: I like it +7 Vote: I do not like it

since it was first round coordinated by arsijo it shouldn't be unrated

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I think, the round should be rated

»
8 months ago, # |
  Vote: I like it -16 Vote: I do not like it

test cases for div2 C is very poor!!!! It accepted O(n^2) solution!!!! very sad!!!! make strong test cases!!!

  • »
    »
    8 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    std::set::lower_bound time complexity is log(n).So it is nlogn

  • »
    »
    8 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The tests are fine. Your solution is definitely , because insert, erase and lower_bound operations are .

  • »
    »
    8 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I need to add something.As for set/multiset/unorder... we need to use the std::set::lower_bound,if we use std::lower_bound.Time complexity will be very large.One AC,another TLE. If you already know it, you can ignore it.

    • »
      »
      »
      8 months ago, # ^ |
      Rev. 3   Vote: I like it 0 Vote: I do not like it

      my solution is O(nlogn)... I knew that!!!! but the following code of a participant is of O(n^2):

      int main()
      
      
      {
          int n;
          cin>>n;
          int a[n];
          for(int i=0;i<n;i++){
              cin>>a[i];
          }
          sort(a,a+n);
          int cnt=0, index=1;
          for(int i=0;i<n;i++){
              int flag=0;
              for(int j=index;j<n;j++){
                  if(a[j]>a[i]){
                      cnt++;
                      index=j+1;
                      flag=1;
                      break;
                  }
              }
              if(flag==0 || index==n) break;
          }
      
          cout<<cnt;
          return 0;
      }
      
      • »
        »
        »
        »
        8 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        That solution is O(n log n) because even though there are 2 nested loops, second for will be actually iterated only n times in all algorithm.

        So, O(n log n + n) it's roughly O(n log n)

      • »
        »
        »
        »
        8 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        Here are some optimizations. ~~~~~ if(flag==0 || index==n) break; ~~~~~

        Sometimes there will be some magical operations.

        • »
          »
          »
          »
          »
          8 months ago, # ^ |
            Vote: I like it 0 Vote: I do not like it

          Oh yes!!! I got it!!!! I didn't notice in that way!!! this solution time complexity is O(nlogn).. thanks

»
8 months ago, # |
Rev. 4   Vote: I like it -10 Vote: I do not like it

It could be semi-rated :P just kidding... Although I did not face any problem during the round, but div2-D was too hard for me....

»
8 months ago, # |
  Vote: I like it +7 Vote: I do not like it

Rated

»
8 months ago, # |
  Vote: I like it -10 Vote: I do not like it

the contest initially had too many errors which were clarified later more over div2 D and E were just out of the league so this round must not be rated

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I have had a good contest. And now there is confusion about the round!!!

»
8 months ago, # |
  Vote: I like it +6 Vote: I do not like it

Extra 10 minute is given. So this round must be rated.

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Scoring distribution should be changed

»
8 months ago, # |
  Vote: I like it +6 Vote: I do not like it

Ratings were updated for div1 people, so it will be rated i guess

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

I would like it to be rated

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

IMO the round should be rated considering the fact that round 485 was still rated even with the endless queue. The problems with this round were minor, the only one worth considering was with the "TLE" instead of "WA". I suggest to make the round unrated for those who got incorrect message on div 1 C and would have a drop in rating because of it. Btw there were +10 minutes for the round. And as for the gap between div 2c and div2d, i don't think should matter really much because after all, everyone got the same problems.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Hey MikeMirzayanov, I haven't slept yet and it's 4:00 AM in my country now.

The only reason being that I am waiting for seeing if the round will be rated or not. I think you have had enough opinions from the community to be able to come to a decision.

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Rated

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

In this round was not big issues, so this round should be rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I think that there are no mistakes in tasks conditions (no errors in div1ABC, because I successfully solved them) => round must be rated. I was interested in hacking problem A. It was exciting.

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

With due respect, please atleast give us some updates. Like what is the decision. How much time will it takes to make the decision, or anything at all. Please. I didn't mean to be offensive, but please some updates....

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

I think it should be rated

»
8 months ago, # |
  Vote: I like it +3 Vote: I do not like it

It should be rated.

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Thanks for making this round rated! :)

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

It should be rated

»
8 months ago, # |
  Vote: I like it -6 Vote: I do not like it

confusing is ended the contest is rated .

»
8 months ago, # |
Rev. 3   Vote: I like it 0 Vote: I do not like it

What's wrong with the checker? The answer isnt in range 0-3. MikeMirzayanov

40296624

»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

It should be rated but there is no one hack my solution B and C, system test is not strong enough I think.BC

»
8 months ago, # |
  Vote: I like it +33 Vote: I do not like it

The round being rated was actually positive for me, but I'd be OK with either decision. The incorrect behavior of the interactor in D2E really affected my participation in this round. I did my first submission 40 minutes before the round ended and due to receiving Idleness Limit Exceeded instead of WA on too many queries I spent most of the time after that debugging my scanf/printf statements, instead of debugging my algorithm. This should definitely be avoided in the future; I hope that a little more care is given to the problem statements in future rounds.

Thanks anyway for the effort of everyone that organized this round!