Invitation to Infinity 2k21 (Rated for div2 & div 3)

Hello Codechef !!

I, on behalf of the InfInITy Team, would like to invite you to take part in the 5th edition of IIIT Pune’s flagship coding event InfInITy 2k21, a rated contest hosted by CodeChef IIITP Chapter, which will take place on Wednesday, December 22, 2021, at 20:00 ISTUTC+5.5. It is a 3 hr long contest.

The contest is Rated for Div. 2 and Div. 3 on Codechef, but Div. 1 coders are encouraged to participate unofficially as there are prizes for top participants in combined(Div. 1 + Div. 2) ranklist. We’d be offering you 8 problems in Div 2 and 7 problems in Div 3 with varying difficulties.


  • Top 3 performers (Div1 + Div 2 combined) will be awarded cash prize of INR 10000, 7000 & 3000 respectively. Top performer of Div3 will be awarded INR 2000.
  • Top 2 Indian participants will be rewarded INR 4000 & 2000 respectively.
  • Prizes worth INR 10000 specially for IIIT Pune students.

Contest Link :
Contest Timing : 20:00 to 23:00 IST
Registration For Prizes : Infinity Website or Google Form

I would really like to thank:

For any queries contact:
Editorials for all the questions will be posted shortly after the contest ends!.

Past problem sets for the event: 2020, 2019

I hope you will enjoy solving the problems. Please give your feedback on the problem set in the comments below, after the contest.


Why is penalty here 20 min whereas for cook-off penalty is 10 min.

Fixed. Penalty is 10 min.

Reminder: The contest begins in 10 mins

here is my submission link. I couldn’t find any problem in it. Can anybody help me to find the mistakes, please!
problem : DALGONA
contest link: Contest Page | CodeChef

Check your answer for the case n=2. It isn’t a perfect square.