MikeMirzayanov's blog

About Unrated Educational Codeforces Round 121
By MikeMirzayanov, 3 years ago, In English

Hello, Codeforces.

Unfortunately, we have to declare the round unrated.

Absolutely, these are not issues of the side of Codeforces code, but rather it is a hardware issue. Probably, electricity, power unit or something else. This led to unexpected repeated reboots of the server with the database. I hope that we will be able to quickly deal with this.

We apologize to the writers of the round and its participants.

P.S. Please, do not downvote the round announcement: the writers are not to blame for what happened. And in general, this time it is difficult to blame someone. Sometimes hardware fails.

Mike.

  • Vote: I like it
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  • Vote: I do not like it

Comments Comments (87)
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3 years ago, # |
  Vote: I like it +119 Vote: I do not like it

Have you considered migrating to the cloud? Perhaps it would be too expensive?

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    3 years ago, # ^ |
    ← Rev. 2   Vote: I like it +17 Vote: I do not like it

    I think if that is the problem they can easily ask people in codeforces to donate money as much as they want and then there may be stored good money (or may be I am wrong because maybe it needs much money during the year)

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    3 years ago, # ^ |
      Vote: I like it +124 Vote: I do not like it

    Of course, this will cost many times more. In addition, similar problems occur in data centers too.

    In this case, what I and geranazavr555 are doing at the current time would help. Just a couple of days ago, he took from a delivery point an adapter so that it would be possible to add fast disks to another server. After some time, we will have a fully functional slave, to which we can switch in case of failure of the main server. Now it is, but it will not handle the huge load of the round (it is needed for backups).

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      3 years ago, # ^ |
      ← Rev. 7   Vote: I like it +403 Vote: I do not like it

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      3 years ago, # ^ |
        Vote: I like it +37 Vote: I do not like it

      You are walking on the edge here.

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      3 years ago, # ^ |
      ← Rev. 2   Vote: I like it +26 Vote: I do not like it

      Hi Mike, As you might already know, cloud providers like AWS, Azure etc. provides a very good SLA. We can have our servers hosted in multiple regions so even if there is a power outage at one place, we can still serve from other regions (with little degraded experience sometimes). These servers can also handle huge loads easily by horizontal auto-scaling (except for sudden burst in load since those would require some pre vertical scaling as well). However the cost to use such infra would be obviously high.

      But given that we have such a huge community of programmers now, we can try for donations. If we are able to raise enough fund to use these cloud providers for say 3 years then we can think of migrating.

      One interesting problem to solve here is to come up with an approximate estimate :)

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        3 years ago, # ^ |
          Vote: I like it +164 Vote: I do not like it

        I believe tech giants and fortune companies should sponsor CodeForces. Because directly or indirectly they are getting a huge number of top-class employees from this community.

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          3 years ago, # ^ |
            Vote: I like it +21 Vote: I do not like it

          Such sponsorship is not always a good thing. It isn't uncommon for cloud service providers to initially donate their free services to open source projects (or non-profit organizations that are doing something good for the humankind). But then these cloud service providers eventually stop their sponsorship and start charging a lot of money after people get used to the service and can't easily move away. Here's one example: https://www.theregister.com/2021/04/01/freedesktoporg_migration_from_google/

          Also an online judge platform may have some extra very specific requirements, which are non-typical for the other cloud users. For example, the execution time of a submitted solution has to be reproducible with a good accuracy.

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          3 years ago, # ^ |
            Vote: I like it +118 Vote: I do not like it

          The number of upvotes on this comment really show how naive some people are. Let's put yourselves as a marketing director of a big company and think of how you would convince your company to sponsor CF. It's kinda easy to spend others' money, right?

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            3 years ago, # ^ |
              Vote: I like it 0 Vote: I do not like it

            They will not do it only for their promotion. They will do it also to continue the supply chain of quality candidates. So, I don't think some sponsored round or activities which help CodeForces to raise their fund will be bad.

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          3 years ago, # ^ |
            Vote: I like it +126 Vote: I do not like it

          I don't like this. With big sponsorships come big expectations.

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        3 years ago, # ^ |
          Vote: I like it +41 Vote: I do not like it

        I would absolutely donate this site literally helped me get a job so least I'd bs thrilled to donate.

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        3 years ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        agree

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3 years ago, # |
  Vote: I like it +34 Vote: I do not like it

It's all part of the game.

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3 years ago, # |
← Rev. 2   Vote: I like it -73 Vote: I do not like it

It's good that the round became unrated, since I solved only problem A))

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3 years ago, # |
  Vote: I like it +14 Vote: I do not like it

No problem,we trust technical team of codeforces,they are putting lots of efforts.

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3 years ago, # |
  Vote: I like it +77 Vote: I do not like it

It's surprising to me that Codeforces still runs on an old Thinkpad in the basement. If running it off the cloud is too expensive, perhaps having a fallback on the cloud that you could turn on when there are technical issues?

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    3 years ago, # ^ |
      Vote: I like it +26 Vote: I do not like it

    Wait, this Thinkpad hosts the backend and also runs all solutions? Is that for real?

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      3 years ago, # ^ |
        Vote: I like it +66 Vote: I do not like it

      nah, its hosted on a lemon powered potato

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        3 years ago, # ^ |
        ← Rev. 2   Vote: I like it +54 Vote: I do not like it

        It runs on a B360M-DS3H

        This is what I found by doing system("systeminfo | FINDSTR \"System model\"") on custom invocation

        System Boot Time:          1/16/2022, 1:20:27 AM
System Manufacturer:       DEPO Computers
System Model:              B360M-DS3H
System Type:               x64-based PC
System Directory:          C:\Windows\system32
System Locale:             en-us;English (United States)

=====
Used: 77 ms, 6316 KB
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          3 years ago, # ^ |
            Vote: I like it +12 Vote: I do not like it

          is there only 1 machine that runs whole cf?

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            3 years ago, # ^ |
              Vote: I like it +18 Vote: I do not like it

            To be fair, that's more than enough. At a specific time I only see about a dozens of submissions got executed, which only take a few milliseconds of the CPU load. If you put in about 12-16 physical cores with probably 128-256GB RAM it should be able to handle the whole site without any problems. In the end this is just a very modest estimation. We're in 23rd century already, there is no need for multi-server setup to run a website or a web application.

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              3 years ago, # ^ |
                Vote: I like it +44 Vote: I do not like it

              Hey, but not all of us are time travelers from the future like you are :(

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3 years ago, # |
  Vote: I like it +11 Vote: I do not like it

It is only a game.

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3 years ago, # |
  Vote: I like it +4 Vote: I do not like it

It's all part of Aizen's plan

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3 years ago, # |
  Vote: I like it +6 Vote: I do not like it

It's okay MikeMirzayanov. All the best for hosting the next round properly.

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3 years ago, # |
  Vote: I like it -233 Vote: I do not like it

Just a suggestion, you can make rated for the participants who will be getting positive delta, and for the rest, contest can be made unrated. Everyone will be happy and also it's fine as everyone got the same time just the contest duration got reduced. Also, it's not the fault of the participants then why should they suffer?

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    3 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    It's only my humble opinion, but I guess it'll be unfair: imagine a 1500 rated specialist (let it be A) solving 3 problems fast and getting 1000th rank and high positive delta, and everything shuts down. Imagine if it didn't, he wouldn't have solved any more, but 3000 people with the rank below him would solve 4 problems and A would have had 4000th rank or lower, so he would've had negative delta, and you suggest that we add him rating for his performance. I know that 3000 people can't solve 4 problems, cause normally <=1500 ppl solve at least 4, but no one knows what could've happened. I'm sorry if I offended you or any specialists

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      3 years ago, # ^ |
        Vote: I like it -35 Vote: I do not like it

      No one knows what would have happened if the contest was for 2 hours. Maybe that specialist which you mentioned, may have solved even E. Making unrated for long queues is fine as in that case there is an unfair advantage to the participants who solved in one go over the participant who submitted and got a wrong answer verdict after 10 minutes. In today's case, no one has got any advantage, so it's reasonable to make it rated for participants who will be getting a positive delta and everyone will be happy.

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        3 years ago, # ^ |
          Vote: I like it +15 Vote: I do not like it

        Yes, no one knows what would have happened. The positions the participants got doesn't reflect what their actual skill levels is. For this reason I think it is better to be unrated.

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          3 years ago, # ^ |
            Vote: I like it -36 Vote: I do not like it

          You did not get whatever I was trying to convey. First, even standings at the end of any contest do not reflect their actual skill level for some users. Also, in any 2hrs contest minutes, then there must be some user who ended with a rank around 1000, could have ended up under 200, if the contest would have been extended by just 5 minutes. What I am saying that everyone got around 1hrs 15 mins, so it's reasonable to make rated for participants who will be getting a positive delta. Why should other persons bother about someone else's rating?

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            3 years ago, # ^ |
              Vote: I like it +18 Vote: I do not like it

            Because ratings will inflate overall and in my opinion it may ruin the legitimacy of ratings if we allow this to consistently happen for unrated rounds. I was thinking that taking the square root of the delta is an idea but also not really realistic.

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            3 years ago, # ^ |
              Vote: I like it +1 Vote: I do not like it

            Why are you craving so much for ratings man. Ratings indeed brings motivation but when motivation turns into greed it also brings a huge demotivations.

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    3 years ago, # ^ |
      Vote: I like it +39 Vote: I do not like it

    Also, I think it does not make sense to have positive delta without negative delta, its like yin and yang...

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    3 years ago, # ^ |
      Vote: I like it +20 Vote: I do not like it

    It would only cause rating inflation.

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3 years ago, # |
  Vote: I like it +12 Vote: I do not like it

This happened once in a year (or maybe even more rare). so, saying blaming codeforces is not on the cloud is the reason for it seems like a big stretch to me.

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

if possible don't make it unrated because site crash was for everyone

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I know that someone play well in this round, including me. But there is also someone who just want to submit the time the problem happened, well, also including me. It's empathetic for you to understand that there is huge difference between interruption like this and normal ending. Just imagine that the site crashed just after you finished programming your code and prepare to submit, then you can put yourself in.

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3 years ago, # |
  Vote: I like it +200 Vote: I do not like it

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3 years ago, # |
  Vote: I like it +26 Vote: I do not like it

Please check if some of your employees are giving contest and performed very bad so they caused some hardware issue LOL:)

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3 years ago, # |
  Vote: I like it +7 Vote: I do not like it

Even though I performed better in this round than in others, I understand the situation and will continue to support this platform!

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3 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Can we add another Educational round by end of Jan to make up this one ??

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3 years ago, # |
  Vote: I like it -20 Vote: I do not like it

please keep another div 2 contest before the next one if possible MikeMirzayanov

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

PLS, keep another contest before Codeforces Round #767 (Div. 2)

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3 years ago, # |
  Vote: I like it +3 Vote: I do not like it

Hoping for a round before the next div2 to compensate for this one. Nice questions today.

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3 years ago, # |
← Rev. 3   Vote: I like it -65 Vote: I do not like it

Could you please give everyone their delta if it is positive ?

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    3 years ago, # ^ |
    ← Rev. 2   Vote: I like it +5 Vote: I do not like it

    it will be kinda unfair for others cause they could have got +ve delta during the down time or something so the better choice is to make it unrated

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      3 years ago, # ^ |
        Vote: I like it -30 Vote: I do not like it

      For them, it's still unrated, and why should they bother for others' ratings?

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        3 years ago, # ^ |
          Vote: I like it -11 Vote: I do not like it

        yeah

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        3 years ago, # ^ |
          Vote: I like it +18 Vote: I do not like it

        Because of rating inflation. It's like you have money, and the state beginning to print and distribute the same currency, so that you can not buy anything. Or if everybody gets +1000 to his rating, it makes no sense.

        Or another explanation. Percentil is more important than rating. Someone who has not even participated in this round, expects that his percentil will not change. Some winners will overtake him, but the same amount of participants would normally fall under his rating level. If there are only winners, it disadvantages all non-participants.

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      3 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      but it is unfair for people who thought it is impossible to continue for that the crash lasted a long time.

      Things will be different if the problem is solved in minutes.

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3 years ago, # |
  Vote: I like it +2 Vote: I do not like it

Goodbye my dreams of solving 3 problems in a rated contest.

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3 years ago, # |
  Vote: I like it +1 Vote: I do not like it

I'm actually up rank, but it's ok.

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3 years ago, # |
  Vote: I like it +3 Vote: I do not like it

It's all good, even though it is unfortunate, the writers are not to be blamed. Good luck to everyone in future CodeForces contests.

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

dompit

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

ah shit happens

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3 years ago, # |
← Rev. 6   Vote: I like it -49 Vote: I do not like it

I want to laugh and cry)

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    3 years ago, # ^ |
      Vote: I like it +24 Vote: I do not like it

    Just my opinion, but I don't think you should think about rating at all until you get to something like $$$\geq$$$ stable-mid-blue, simply because, I think until that point what's more important is to get problem-solving experience and some skill, and attaching it to rating just gets in the way of that.

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      3 years ago, # ^ |
        Vote: I like it +24 Vote: I do not like it

      Why is it different at any other rating? (also for me rating always has been one of the greatest motivations)

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        3 years ago, # ^ |
        ← Rev. 2   Vote: I like it +14 Vote: I do not like it

        I think it boils down to:
        1. When you hit $$$\geq$$$ stable blue, you have enough contest experience (of course, this might not always be the case) to not be too perturbed by rating loss, and (hopefully) you don't learn only stuff which "is expected to be used in Div2 C" or similar. I have seen a lot of lower rated people stuck in the loop of "I don't know $$$X$$$ because it doesn't appear in problem $$$Y$$$, and I can't solve problem $$$Y/Y+1$$$ because I don't know $$$X$$$.", or, "I solve only $$$\leq Y$$$ rated problems because I am rated $$$X$$$, and I am rated $$$X$$$ because I only solve $$$\leq Y$$$ rated problems."
        2. Rating is definitely a great motivating factor! But, just my opinion, at something below stable blue (of course it's not a very strict range), it is very easy to start worrying about rating and skipping contests/using alts/similar things, or just in general, focusing more on less important things than on solving problems.

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3 years ago, # |
  Vote: I like it +7 Vote: I do not like it

No problem! We trust the team of codeforces

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3 years ago, # |
  Vote: I like it -38 Vote: I do not like it

What if we distribute processing power between computers based on blockchain kind of technology, with specific profiles for each kind of CPU it can work and we could track clock cycles instead of time used by a specific CPU.

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3 years ago, # |
  Vote: I like it -29 Vote: I do not like it

HOW COME U HAVE ELECTRICITY CUT OFF, I MEAN YOU GUYS ARE RICH ENOUGH TO BUY AN INVERTER FOR SUCH POWER CUT SITUATIONS. I DO NOT MEAN TO OFFEND, IF U DON'T HAVE THAT KIND OF MONEY.

YOU CAN ASK YOUR USERS TO DONATE VERY SMALL AMOUNTS SO THAT YOU CAN BUY AN INVERTER.

MikeMirzayanov geranazavr555

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    AND ON TOP OF THAT THEY DIDN'T EVEN CHARGE THE LAPTOP ON WHICH THE SITE WAS RUNNING ELSE IT WOULD HAVE GIVEN A BACKUP OF A FEW HOURS ATLEAST.

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3 years ago, # |
  Vote: I like it +61 Vote: I do not like it

Can you put a "Donate" link?

Some of us would like to help a hardware situation. This can result in a hardware renewal/duplication over some time.

If you do, you should also consider "Top donors" list similar to "Top contributors"

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3 years ago, # |
← Rev. 2   Vote: I like it +13 Vote: I do not like it

Codeforces is loading really slow for me for past 3 days. Main reason why I couldn't take part in last div 2 round.

--- www.codeforces.com ping statistics ---
12 packets transmitted, 9 packets received, 25.0% packet loss
round-trip min/avg/max/stddev = 338.355/366.281/434.326/29.461 ms

UPD — Working fine now :)

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

i just wanna say that codeforces is so slow when compared to other programming websites like hackerrank, hackerearth, atcoder and codechef. my internet connection is very fast, but when i use codeforces it takes too much time to open and when i submit any solution it also takes too much time. i am noticing this from a long time. all i wanna say is lodeforces is fucking slow.

try to improve it mikey.

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    3 years ago, # ^ |
      Vote: I like it +25 Vote: I do not like it

    But for me codeforces opens faster than other sites like codechef and atcoder ! I think this is a weird problem :|

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    3 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    I guess it's partially because of CF server is in the other country for you (and CodeChef is in the same country).

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

You know I expected my rate to go up at this round but sadly this happened thank you Mike for fixing the problem but we wish it never happen again

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3 years ago, # |
  Vote: I like it +1 Vote: I do not like it

Thinks like this happens.No issues :) Kudos to the writers.

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3 years ago, # |
  Vote: I like it +1 Vote: I do not like it

ok

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