Invitation to CodeChef January Lunchtime 2021 [Replay of Codeflows]

Subject: Invitation to CodeChef January Lunchtime 2021

We invite you to participate in CodeChef’s January Lunchtime, this Saturday, 30th January.

Time: 9 PM - 12 AM IST (Please note the change in time)

There will be 3 divisions, each division containing 6 problems!

This Lunchtime is going to be seriously epic because we have ByteDance joining us as official contest recruiters. The globally established tech giants will be looking to hire for multiple positions for their Singapore office, including - Algorithm Engineers, Backend Engineers, Data Engineers, Data Scientist, Machine Learning Engineers, Research Scientists, Frontend Engineers, Quality Assurance Engineer, Research Engineers, Software Engineer, and Site Reliability Engineers.

The problems of this contest are offered by Codeflows, and are sponsored by Bending Spoons.

Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef’s contests, you can share them here.

Joining me on the problem setting panel are:


Top 10 Indian and top 10 Global school students from ranklist will receive certificates and CodeChef laddus, with which they can claim cool CodeChef goodies. Know more here.

The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.

Admin Note:

This Lunchtime is a replay of Codeflows, so most problems do not have subtasks. We have added some easier problems for Div3 and Div2 problemsets, and the contest is delayed from its usual time to avoid clash with the final round!

Good luck and have fun!


Lunchtime more like Dinnertime, Lunchtime was the only contest i could attempt for the entire duration as literally every other CP contest ends at late night…


Hope this time there will be no server issue :slight_smile:

Replay of codeflows mean ??

Abey yaar, improve servers showing 503

@ashishgup there are rumours going on that you decided to make in unrated. I don’t think that it would make things any better. Currently, some people are disappointed about the queue, but there is always an option to solve other problems while waiting for your previous submissions to get judges. If, however, the round gets unrated, the people disappointed about the queue will still be disappointed about the queue, but other people who performed well in these uneasy conditions will get even more disappointed. This decision won’t fix anything but will introduce new problems.


It has been announced you can refer to contest page of January Lunchtime

There was no discussion with the community about the formal criteria of when the contest gets unrated and when it does not. I find it to be much more unfair than the queue issues, which are the same for all users, and therefore more-or-less fair.

Well I don’t know any site in which decision about letting the contest rated or making unrated happens .The thing is that I believe long queue is unfair but though I got a good +ve in last contest(which doesn’t really matter to me in this account) I believe the last few contest should also be made unrated with this one


See? When there are no formal criteria, everyone feels unfair about one or another contest where they either performed badly because of the queue but it got rated, or they performed well despite the queue but it got unrated. It would be better to at least have some sort of stability.


Yess in this thing I totally agree to you

By that logic, no contest should ever be unrated, no matter how long the queue was?

The issue is:

  • First 1 hour was plagued by constant 503 server errors, which was obviously very frustrating and inconvenient for a lot of the participants.
  • Some users were not able to submit their solutions due to a server-side issue, and while this number might be at around 5% of the participation, that is still relatively large
  • The queue issue happened at end, where the solutions were actually getting judged, but the verdict was not shown and these submissions kept running for 30+ minutes towards the very end.

I agree that the unrating is obviously sad for people who had +ve delta, but that should never a factor for deciding whether a contest is rated or not, because in every unrated contest, approximately half the participants will always satisfy that criteria.

For me, the thing is: Was the contest fair to the participants? In the end, I don’t think it was.

For people comparing it to CookOff: CookOff only had loading issues (503s) at the beginning, for the last 2 hour - 2 hour 15 minutes, site functioned perfectly and there was no queue during the contest.

For LTIME, the 30 minute queue was the breaking point - I mean, it’s still all well and good if your solution is AC and you move on to solve a different problem, but what about WA/TLE/RTE? You waited 30 minutes, kept checking in between, tried to solve some other problem in the meantime, but when you come back - you won’t even have time to fix this - how is it fair?

Overall, I don’t like making it unrated either - mostly because of the setter’s efforts that went into the contest, but it’s something that just unfortunately had to happen ):


Till when can we expect editorial?

@ashishgup I hope they make a comeback within 1-2 months as long challenges are plagiarised. So many people only give short contests.

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Yes hopefully. I prefer short contests as well.

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@ashishgup In no way it is right to upload video editorial for each probelm before written editorials.

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That’s honestly upto the editorialists - the video and text editorialists are both given the problems, but since 1 person has to make 1 video editorial (there are a lot of video editorialists) as opposed to one text editorialist per contest, I think it may happen that the text editorials come a bit late…


Well then sorry to say it looks like Codechef is tilting towards video editorial then some brilliant written editorials , I am not saying that video editorial are bad its just like written editorials have a different place .


I agree, we will try to have the text editorials released at the same time.


This was my first contest to get rated . I had lots of expectation from codechef . I have voted on recent poll to get rated this contest . Please consider our more than 80% poll of coders .