Invitation to Byterace 2k20 on CodeChef [Rated for Div-2]

Hey Codechef Community!!

Greetings from NJACK, the Computer Science Club of IIT Patna,

We present to you ByteRace 2k20, as a part of our annual technical fest, Celesta.

The contest will be held on Codechef and is Rated for all Div2 participants! (Rating < 1800)

Date and Time: 29th December 2020, 20:00 IST to 22:30 IST. (IST = UTC+5.5)

The contest will be ICPC style with 7 problems.

We would like thank our problem-setters: V_S_M, jenishmonpara, aditigoel, Nihal0002, 100gods and our organizers: kunj017 and hackcyborg.

Special thanks to jtnydv25 for coordinating the round.

The problems have been tested by nightmare05, chan_iitp, aditya_sheth, and me.

Contest Link


Global Ranklist

  1. 5000 INR
  2. 3000 INR
  3. 2000 INR

Indian Ranklist (Apart from top 3 global)

  1. 2000 INR
  2. 2000 INR

IIT Patna Participants

  1. 500 INR
  2. 500 INR

Coupons and goodies worth ₹5k to 20 random participants!
To register for prizes fill this form before the contest: Form


Is there a possibility for having a separate ranklist (kind of unofficial) for DIV1 participants,even a combined will also be not a problem.

Why do you want a separate ranklist though ?

Even if it’s combined it’s cool, I don’t know whether the ranklist will show DIV1 participants too. :sweat_smile:

Now I understood your point, it’s a valid question indeed. @darklight13 can you please clarify if DIV-1 people will be featured in any rank list or not as in the last only DIV-2 rated round I got to know my rank after a month or something when the combined rank list was released(that too on a google excel sheet :expressionless:)

Yeah, there will be a separate ranklist for DIV1 participants, I think it will be live as well. I will update one I get confirmation from codechef.

That would be great! thanks for informing

1 Like

It will be live, got confirmation from codechef.


I will publish a livesolve/editorial on my YT channel after the contest, everyone interested is welcome to come by and watch interesting problems, I hope it will be helpful for you guys.


Will questions contain subtasks?

No, the contest will be ICPC style so binary marks on problem and each problem is of equal points.


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This was a good Div 1 contest I feel , It had awesome Problem Distribution for Div 1 , atleast The ranklist and no. Of AC’s for the problem says that :slight_smile: :sweat_smile:


Good questions , really impressed.
Can someone tell me the approach for 3 one , couldn’t get it even after trying for 2 hrs.
Thank you in advance.

Range Updates on Segment Trees BUT with different values for each index in the update range. - Codeforces

1 Like

You can use Difference Array | Range update query in O(1) - GeeksforGeeks
trick and do prefix sum twice instead of once.
Time complexity : O(n)
Segment tree is an overkill


yup , i’ll try to do that,thanks for the hint.

how ? we have to add the AP.