Invitation to Alohomora 2021

Hello CodeChef,

RECursion, CodeChef NITDGP Chapter, is organizing an ACM-ICPC style-based contest ALOHOMORA. The contest will be held on 11th June at 21:30 IST.

The contest will be held on the CodeChef platform. There will be 8 problems which are to be solved in 2 hours and 30 minutes.

Participants need to register themselves in teams of 3 (maximum).


Cash Prizes worth ₹5K and ₹3K for Top 2 Performing Teams
Cash Prize worth ₹2K for Top Performing Indian Team
250 CodeChef Laddus for Top 3 Performing Teams

Exciting Goodies from Digital Ocean for Top 3 Performing Teams from NIT Durgapur
100 CodeChef Laddus for Top Performing Team from NIT Durgapur

For further information, contact:
Nikhil Vashistha: +91 9835274836
Anupam Singh: +91 7054394459


Till when are registration open ?

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Hmm, contest name is a HP spell and the poster is of Pokemon.




Has the contest been cancelled? as I can’t seem to find it on the compete page as of now

Toggle the “Show all contest” icon. Above present coding contests.

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Oh thanks, I didn’t see that at all, my bad.

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Reminder : Contest starts in 2 hours. On the contests’ page, toggle the “show all contests” button to see the link or directly access it from here . GLHF!

The contest starts in 10 minutes. Good luck everyone.

How to solve JPUFF?
(in case the solution is based on flows, can anyone provide me with a neat implementation?)

I didn’t get time to implement but I think it’s just a bipartite matching problem on the divisors. I mean say we have 2 x N nodes,[1 → N and A_1 → A_n]. then we make edges from A_i to it’s diviors and then we’ll have to find any perfect matching.

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Find a bipartite matching. On left we keep the N numbers and add an edge between A_i and all of its divisors. Didn’t code but I guess it should work.

I thought of the same exact thing but I don’t know how to implement it :frowning:

Any ideas on the implementation?.
Instead I added divisors which are in the range 1 to N for each A[i].

Yes, I don’t see any problem with that. Didn’t that work ?

Ford Fulkerson Residual graphs. All edges with flow 1 are part of the answer.

I missed the case with disconnected component in my code and ran out of time to debug.

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Bro how did you solve the Poke Dice problem I thought it was a easy one, but it ate me up.

Would the solutions be made public?

Divisibility by 5 and lowerbound 5m and upperbound 55m