Hello, Codeforces!
I'm very glad to invite you to Codeforces Round #639 (Div. 1) and Codeforces Round #639 (Div. 2). This contest will take place on May/06/2020 17:35 (Moscow time). In both divisions, you will have 2 hours 15 minutes to solve 6 problems. The score distribution will be announced closer to the start of the contest.
Of course, this round would not be possible without the help of many people, who I'd like to thank:
- isaf27, for coordinating this round, and helping with solution ideas.
- My ICPC teammates Kuroni and strongoier, and coach cnh355, for encouraging me to pursue competitive programming. In particular, I'd like to thank Kuroni for being so spectacularly bad that a barely-orange user like myself actually has a place on our team.
- 300iq, antontrygubO_o, Ari, ffao, fpc_coder, gamegame, Kuroni, user1324641, McDic, richzli, and VilgefortzOfRoggeveen for testing and providing valuable feedback.
- KAN for checking the problem statements, making them even clearer.
- MikeMirzayanov for providing the Codeforces and
MonogonPolygon platforms.
I've done my best to write clear problem statements and strong pretests. Don't forget to read all problems, and I hope you enjoy the round. Good luck!
Because I know you all have so many questions, I have compiled an FAQ:
- Q: Is it rated?
- A: Yes.
UPD
Here is the score distribution.
Div. 1: 500 — 1000 — 1500 — 1750 — 2500 — 2500
Div. 2: 500 — 1000 — 1500 — 2000 — 2500 — 2750
UPD Unfortunately, this contest is delayed due to problems in the Codeforces system. It is temporarily scheduled, but I will update this announcement when a final decision on scheduling has been made. It is sad that my contest is delayed, but let's be grateful that the issue was detected early instead of arising in the middle of the round. On the bright side, this may be the earliest announced score distribution in Codeforces history.
UPD The final decision on scheduling is to keep it as is. The contest will take place on May/06/2020 17:35 (Moscow time).
UPD Unfortunately due to the long queue and other issues, the contest is unrated. There was also a bug that gave us trouble in answering your questions. I'm sorry if you asked a question that went unanswered for a long time. I promise we did our best to answer as many questions as we could! Despite all the problems, I hope you enjoyed the problemset!
UPD Editorial
As a tester, I enjoyed the problemset! Participation is recommended :)
Would be strange and funny if you said "contest is bullshit".
Can't disagree
But if that was what he thought of the contest, he probably wouldn't post anything at all.
Some testers do that
I just downvoted you just because I hate Petyr Baelish =))
update: Just a joke! why so serious?
downvote for u ^ _ ^
that should be a really positive feedback if i get it right xD
good one.
I hope it means "go and increase your rating":D
+1, I had fun testing this too!
Don't forget to read all problems
It's not sorted, right ?it's ok to postpone it instead of doing unrated round.
Underrated comment
lol :p
sad
-looks like bait.
-yup definitely bait.
sure and I have a good feel for the contest
When reds say I enjoyed solving a problem, for me, it generally means that I will enjoy reading editorial for this problem after the contest.
quite true.
How people get the chance to be a tester for any contest? :)
Most likely you will get a message where somebody asks for your help.
Like this is random?
Well, somebody chooses to send such a message to you, or do not. So it is not really random.
There is a channel where coordinators can ask for testing. It is not public of course. People try to cheat even without access to problems.
Most authors usually ask their friends to test.
Codeforces Round #639 lost in queues somewhere....... TRUE. But enjoyed problems.
Very true indeed
very recommended :)
Any specific reason for exactly 2 hours 15 minutes? :o
Yes.
I am intrigued.
And it is?
Long statements maybe.
Ok now it's making sense why extra 15 minutes were given. But 15 minutes is very less for such long queues. Should be 6 hour contest atleast.
long queue
long long queue.
queue < long long >
Good luck for you too for 1st problemsetting. Hope we will get a new problem setter who makes good problems.
Btw, the era of "is it rated?" almost ended. Now burning FAQ is "Are pretest strong? Is problem statement short?"
The contest is unrated! Though the problems are really good.
New one has come "Is it queueforces?"
2 hours 15 minutes hmmmmMM
wow another clear statements ans strong pretest contest <3
Is there any specific reason that many people downvote a comment? or just to minus my contribution?? i didn't get any point though.
It's ok bro don't bother too much about downvotes/upvotes.
ok
[Deleted]
panauti
Don't forget to read all problems
It didn't end well the last time the announcement had this text.
Why?
Give virtual on this contest, you'll know :p
Contest: https://codeforces.com/contest/1341
Announcement: https://codeforces.com/blog/entry/76348
Editorial: https://codeforces.com/blog/entry/76479
Well.....
This aged well
Omg. Are you from the future?
Is it rated?
I am a simple man. I see "clear problem statements and strong pretests", I upvote.
Nope, you still can.
Maybe you forgot to say — "Nope, you still can. With many downvotes."
Do you know if it's rated?
Is it rated?
Is it unrated? :P
It is going to be true...
FAQ is surprisingly helpful.
But it contains incorrect information.
Why exactly is it unrated? Yes, I did read the announcement, but isn't the disadvantage the same for everyone? By that argument, the contest would still be fair.
Sitting through such long queue, shifting to another problem only to receive a non-AC verdict after half an hour. Incidents like this during contest is irritating. Some people give up and leave the contest. No one wants to sit through such a contest only because "the disadvantage is same for everyone"
I can feel u from ur profile pic.
How could they get the one FAQ wrong?
LMAO

:)
Please make the pretest as strong as you can (/ T — T )/ .
RIP Kuroni
Hello!! CODE FORCES :)
Help Please!!
I want to set Macros and shortcut templates for faster Programming in C++ .. Please!! tell me how can i set it so that it will be easy to realize.. Please Share your submission code and give me some advice!! :)
Check out this blog C++ Tricks
Thanks!
Why people are giving down vote in this Comment!! Is it wrong to want help from elders!!? :(
Because you wrote it under an irrelevant blog post instead of asking in an appropriate place. And such posts pollute the contest announcement.
OK. Sorry for this. Please, tell me where i can post this!!?
In your current case I think you should just look around on Google and post only if you are sure that for some reason nothing matches what you found on Google.
In general though, make a new blog post.
OK.Thanks!!
You can also ask in your blog. I think this is the right link to create a new blog.
super short FAQ and i have nothing to ask.XD
well now you do
thank u Codeforces... Thank u 1-gon and all writers :D I hope the Statements are short :)) Good luck to all participants and Stay at home with Codeforces *_^
avatar checks out
whats ur point :(
Always keep an eye on baby lions. They will become a grown up lion someday and make your life hard.
avatar checks out, too XD
Your text to link here...
Hope to become mamme_hunter this time 😜
1-gon What is the proof your existance, except for the analogy with names of other polygons?
hopefully this round would be like the same as previous one..short problem statements and fast editorial..
I will participate with gratitude for you!
Schools are like:
Taught in Class: Div2 A
Solved for practice: Div2 B
Homework: Div2 C
Exams: Div2 D,E,F
why people are downvoting such a good comment :(
❤
❤ man I thought CF doesn't support emoji, you showed me the path ✌✌
Exams: Div1 D,E,F
Exams: April Fools Day Contest A,B,C
Why is that much negative vote?!
And "Are the statements short?".
Or "Are the statements clear?"
I believe that people just imitate each other
Really helpful FAQ. Thanks
Why there is Pupil in the Div.1 registration?
[Edit : It's fixed now.]
[deleted]
I think that this rarely happens.
Probably because when they signed up, their rating was greater than or equal to 1900, but after a few contests they scored lower
That's only true for the Expert in the registration. What I mention is Pupil in the registration, and it's virtually impossible after the registration CM becomes Pupil because the registration is opened usually within 2 days before the contest. :(
[deleted]
Ramadan Mubarak And Happy Coding
Ramadan Mubarak
Good wishes for all contestants
Edited: Who gives me negative vote for wishing good, I fucked them :)
Striking of the word Monogon . Was it suppose to make u feel cool .. I m sorry my friend u failed to do so.
It's supposed to make me look degenerate.
noice
It was better to 2 hours & 30 minutes .
I hope it's 2 hours.
Good Luck Everyone~!
Another question that everyone wants to know:
Q: Can I participate without rated?
A: G̶o̶ ̶t̶o̶ ̶t̶h̶e̶ ̶h̶e̶l̶l Good question! The answer is no.
Every game is a record of our experience. Although these scores are not rising all the time, on the whole, we have surpassed ourselves in the past. Good luck!
Why did you say that to me?
Anyway what you said is true, except that it does not depend only on luck but also effort!
Wait another 3 days for such emotions
It's how I felt in the previous contest
I like your previous avatar :D
I failed in the last contest,I wish to be Master in this contest. up,up,up !
Don't know about u, but if I participate I am becoming Candidate Master in this round.
isitrated?
Are you kidding?
now you're right about asking that question
Many experts are registered in Div 1 contest!How? And I knew that candidate masters are participants of div 2 contest.Also I was rated in last div 2 contest.But today I can't register for div 2 as rated one.Why?Actually,I'd been candidate master recently...Thanks
Understood the system of my second question.
The experts who are registered for div1 were candidate master before round #638 rating change. They registered for contest before rating change so they are registered in div1. After rating change there rating decreased to less than 1900. This might be the reason behind invalid registration which will be hopefully fixed before contest.
are problems sorted?
Yes, the problems are sorted by difficulty.
Is that rated for Div1 ? :S
last statement was funnny
Monogon System
I am waiting for darklight13 to become blue:)
Score distribution plz!
Queue got freezed before the contest ........ What does this indicates ???
That indicates judging system will be smooth during the contest (hope it will
When you couldn't do anything but you can hope.........
This indicates the rescheduling of the round
Have I not noticed this before or is it the first time a handle is green in the testers list?
i think so too
i hope that this contest will be more interesting as that of the previous contest
because you have you first contest...>
FieryPhoenix contest was excellent hope 1-gon your contest will also be amazing best of luck to you too...!
ready for queue forces
Q u e u e forces
It could be cancelforces if they can't fix this issue on time =))
stupidness, are you from the future?
Q u e u e.......
After the end of the contest will there be any hacking system to any solution? :)
Is it unrated?
it is rated i think
So u want to break worse record?
Good guess
Well, it is....
QQ for the problem setter, I really liked the problem
Hope Simple statements and Good Luck for everyone!!
One general question, why do some Legendary Grandmasters have the First Letter of their initials as black and rest of the name as red? What does the Black character signify?
It looks cooler.
The Legendary Grandmasters have rating over 3000,but the International Grandmasters don't
People whose rating crossed 1900 in the previous contest are still in the participant list of Div2 will they be shifted to Div 1 during the contest?
No, Codefoces takes the rating when you register. If you have a rating of lower than 1900 and you register, then you get over 1900 after you register and before the competition, you are still a division 2 participant.
Must say the FAQ is very informative.... must have been hell lot of a job for the writer!
I am curious about the duration of the contest!!!Can I get the explanation???
I hope this contest will also have short problems and strong pretests like the previous one, At least strong pretests.
Q: Will it be some live stream on YouTube to up-solve the problems straight after contest?
A: Algopedia: https://youtu.be/HneuObfyDtw
Auto comment: topic has been updated by 1-gon (previous revision, new revision, compare).
Why are there two problems with the same score in Div.2 but not in Div.1?
UPD: Sorry for my mistake. I'm used to putting the score distribution of Div.2 at the top when I prepare contests. And personally I think that looks better because the problems are in increasing order.
The two problems with same score are in Div. 1, not Div. 2.
Div 2D is again 2000 points. :( That did not go well for me in the last contest.
new to CF, so can anyone tell me what the score distribution means?
every problem comes with a different score based on difficulty. as the contest proceeds the score of every problem keeps on decreases.
While you're waiting for the contest AOE2 tournament
...well, this is a DauT round.
Thank you for making contest for us. This will help us.
Seems Div2 E and Div2 F are equally tougher.
Why has the contest date changed?
Mike has posted the reasons for rescheduling.
Codeforces is under lockdown due to covid19 for 3 days
The time key of today's contest has been changed?
Hope Problems and scoring remains same!
Wut??? rescheduled, why???
After round is rescheduled for 3 days later
I was very much excited for this round. But unfortunately all go to vain. btw have to wait 3 days.
Q: Is it rated?
A: Well yes, but actually no
Auto comment: topic has been updated by 1-gon (previous revision, new revision, compare).
Just curious if there's any specific reason why the score distribution is not announced much before the contest??
So that people cannot pre-plan strategies or try to guess their way out about the problem difficulties I guess.
Hi, i have a question. The score distribution of div 1 is less than div 2. Why is that?
Why down voting when someone asks question? I know its not the place to ask and his question is literally trash.
Auto comment: topic has been updated by 1-gon (previous revision, new revision, compare).
In general, are you allowed to write a program that basically makes your submission unreadable so it is harder to hack? For example, the program can add comments, remove/insert whitespace, etc but it doesn't change that basic functionality of your submission.
No. Code obfuscation is explicitly prohibited by Codeforces rules.
So the question is WHY don't you want others hacks your program?
If your program really has a bug, others may find it out and correct it for you. Thus you can fix it in the contest in time instead of receiving an unexpected WRONG ANSWER verdict. This case is profitable for you and others.
So my advice is: TRY to write clean programs. (Although I'm still not good at it :v)
Lol. Why is the score distribution for Div.2 higher than that of Div.1?
Because the div1 guys just act if they would have the harder problems ;)
Thanks for the faq. Much appreciated.
Today, i got notice for an internal test (online ) from my college which clashes with this contest . After waiting for 3 days i have to skip this contest , hope its timing can be changed :-(
forget_it lol ,just kidding
Wow! over 2K registration of Div.1, thanks to the delay.
Perhaps it will be the biggest one of the whole time.
Also over 1.6K upvotes before the beginning of the contest. :D
And now about 25000 registration of Div.2!
All the best guys!!!
I hope everything is going fine today and remains fine until contest ends.
We will be live upsolving the round 10 minutes after it finishes on Algopedia: https://youtu.be/E7fiCGAqNJM
I will stream poker after the round here. please donate!
if my bro gives me a microphone I will sing too
Is there any function or something to check runtime before submit a solution? #need_help
If you're on Linux, use the time command or if you're on Windows use the Measure-Command in Powershell.
Comeback!!!!!!!
The network is so unstable and I frequently experience 502 and 504 as I reload
queueforces
Long queue again !! :(
Queue is now infinite, but is exactly one submission assigned to each room ?
Queue > 10 mins rn
Queue > 40 min!
Unrate?
I am unable to submit solution. it's showing "unexpected error".
Waiting like should i move with next question or should stick to it till verdict
Great servers, thanks Mike!
Hi, I registered for the contest but I'm being redirected with the message that I should have registered for the contest when I try to re-register it says that I'm already registered :/
Unable to enter contest area, bad gateway :|
problems are very difficult :(
You can catch my (little) rate. I'm give up for this constest.
The long queue makes it really difficult to analyse the bugs(if any) on wrong submissions since the verdict comes after a long time. This really affects the aura of the contest. Though the efforts put by the contest designers and testers and also by you Mike are great, please consider making this contest unrated.
Getting logged out, timed out on changing pages. Not really able to solve sadly :(
and here I though something is wrong with my browser :(
Getting logged out, again and again!
QUEUEFORCES ...
wtf is wrong with codeforces ................. pretty demotivated
whats up people suffering in queueforces
Every time I try to submit a solution(without knowing my previous verdicts) I am finding myself being kicked out of contest arena kindly look into it
getting logged out again and again stuck in queue since beginning
I was also logged out 6-7 times till now
And again $125658, Karl!
long queue... it will be great if u make this contest as unrated
All codeforces in slow motion.
Is it still rated?
Login-Bad Gateway-Refresh-Logout Repeat
The problems are nice but it's upsetting to see that the website is not working properly :(
I've a very strong feeling that this round will be unrated!
SLOWFORCES
QUEUEFORCES
Looks like this contest can't be a rated contest. Is it so, please make the announcemant!
I really feel sorry for the problem setters, the round was delayed in order to fix everything and still it ends in this horrible way :(
I am not blaming Mike thought, I am sure they did their best :(
But then, this is life. We can just put the best of our efforts!
Over 200 pages of submissions (that's ten thousand) in the queue as of writing... Is this a new record?
Make it unrated already!
Refresh is the new Logout!!
Really!?
I know right, so ironic.
please make this round unrated
The round should be unrated. Even now, I have been experiencing severe session issues. (i.e., I'm being logged out automatically) Even when I go to the m1.codeforces site, the queue is so long that the code I have submitted for Div2 B is not judged in the time I read, conceived, and submitted a solution for Div2 C. Update: The first one was judged after 30 minutes.
Seems like this round was cursed
Make this round unrated.I fill pity for problem setter. Problems were good.
Ya please make this round unrated we are not able to submit also and even logout several times and the queue is persisting for hours
:(
No competition experience, should not be ranked
please unrated div. 2. it's almost post-apocalypse
Due to long queue I am not able to understand whether my solution is correct or not.I request to make round rated.
I'm going to sacrifice my left testicle if the round remains rated.
Congratulations! You protected your testicle!
lmao same here
I will suggest Mike take your testicle and make it rated for you
Please delete this, it's vulgar.
Every time when I am going to refresh, it's automatically logged out, does it only happen for me !!
This aged well.
I am getting logged out for no reason at all :/
Nobody:
Codeforces: Delay the round with apprehensions of queueforces
3 days later
Codeforces: Good to go with the contest
Me: start contest
Codeforces: Double impact — queueforces and "keep logging you out every 10 minutes"
Me: I won't give up
Hour and a half later
Codeforces: Contest is unrated
Me: Let's give up and go read the comments
scrolls to this comment
Me: Bro! Same feels — hit like
Codeforces: You need to enter into the system before you vote
We need quantum computer as soon as possible
This is by far the worst queueforces ever !!
Why the questions about the problems and during the contest are not answered by the problem setters?
Rank 6, +148, and with Div1.D in queue --**unrated**
This round should be unrated.
I Think We have reached 35 minutes of queue. Unrated Contest seems to be inevitable now
Waiting for a submission verdict be like:
The judge queue is too long. I have to wait almost half an hour to get the answer. This is the most uncomfortable Codeforces Round I have ever participated.
Is Div2 also unrated or not? Div1 got an unrated announcement but not Div2, not sure if I should discuss problems with friends who are in Div2 or not.
Mike: We have rescheduled the contest to avoid long queues.
Users right now:
Is it a way to show that we have to be reaaaaaly careful with our submits? Otherwise getting 30 min penalty :D
Long queue + Bad problem statement
Worst Experience on codeforces ever.... I had to login more than 10 times during contest
I think MikeMirzayanov should take it seriously bcz it annoying the contestant.
is Div2 still rated? As there is no such announcement in Div2
Now i got notification that it is unrated and just solve the problem for fun :)
Ok, this is too much. Situations like this happen too frequently on Codeforces. Maybe we should donate even more so you can stop this from happening every 3rd contest or so?
Dear problem setters, please submit your problems to other, more stable platforms. The quality of your problems deserves much more than this.
i mean they could have just added advertisements to codeforces to keep more servers? also I heard they use Windows servers for testing. Maybe Linux would work better? idk
I don't know why people complain about cf when it has bad rounds. It's not so frequent for rounds to be unrated in such a way, when was the last unrated round because of queue issues? Surely not 3 contests ago ... It's hard times for codeforces too, number of participants in rounds doubled during pandemic. And I think at this time we shouldn't have such negative thoughts about cf.
Can we have a contest with hidden verdict?
No
In China, we have 'OI' contest rules, and it works as follows:
Chinese OI rounds, please.
I hate null feedback rules. Newbies should especially hate them.
In fact, the first time I see the long queue, I have pretended to participate in OI rules, and because I have participated in so many OI rounds in China, it seems perfect!
In addition: I would probably become 2900+ had this round been rated.
That's real bold, calling your rating increase based on 0.5 hours of evaluated submissions before the round was announced to be unrated. I've also had very good results in some quickly unrated rounds, guess why.
How about this: make your own website where you'll host contests with these rules. I'm sure all the Chinese LGM-tier contestants will appreciate it for the same reasons as you do.
That looks similar to what Topcoder does.
Is there any Chinese website like CF or AtCoder?
If this round is still rated, I think it is really unfair for contestants as the judging time is too long. It took more than half an hour for a single submission!!!
It isn't rated now
It's unrated.
wtf
Offlineforces:/
Mike: Coronavirus, can't get into our systems. Becoz its not the software based virus, it's a physical one.
Corona: Causes lockdown worldwide, increases the number of participants in contests, blows up servers.
Mike: wtf !
The problems are so cool, so it's a pity that we can't enjoy them completely because of the long queue :( I hope that everything will get better. Live Codeforces!
as expected round is unrated sed lyf :((
Because I know you all have so many questions, I have compiled an FAQ:
Q: Is it rated? A: Yes. Mike: Actually, no.
This is what happens when the contest is postponed by 3 days---> Unrated
the answer to FAQ turned out to be wrong
Besides the long queue, why the overlap between div1 and div2 is too high? So if someone solves all problems in div2, they could be top10 in div1.
Do you really think it's so easy to fc div2? Pfft, please...
Anyways, if this was actually a rated contest without the queue issues, div1 top 10 will definitely not be 4 ACs by end of contest (it's a six-problem round, probably at least 10 people will solve E or F). So your point is pretty much invalid.
Read my comment again. I talked about the high overlap not being easy of solving all problems.
That's the norm for how div1 and div2 rounds work.
The easiest two problems are only in div2, while the hardest two problems are only in div1. Given that the two divisions are directly touching ranges of rating, the overlap makes sense in balancing the difficulty of the divisions.
Also, your premise is that "if someone solves all problems in div2, they could be top10 in div1", which is itself a flawed premise because 1. fc in div2 is actually quite rare, and 2. top 10 in div1 only solving 4 problems is also quite rare.
Now you know how a TopCoder SRM feels like
Declared unrated now. Feeling bad for the contest organizing panel. Though it was a bad experience for all of us, but I still appreciate 1-gon along with the whole contest organizing panel for their efforts. It is not easy to be on the other side of the table. Thank you!
i submitted sol of a in 8 min but it was not showing in submission tab there i reload the page several time around 10 min because i was continuously logged off and my submission was not showing in tab and also not showing in queue either therefore i resubmitted again .and after 5 min of reloading i see two of my solution in queue! miracle ! REWARD -50 points(resubmission) and headache/tension. if site cant handle too much traffic just make more divison to handle lesser participants per division. AGAIN SED LYF MONOGON .
That's... not how divisions work?
The irony is that the one question answered by the FAQ has been answered wrongly.
thanks for wasting my time !!