Greetings Codeforces,

**Competitive Programming Club, AIT Pune** is excited to invite you to **CoDeft 3.0** which will take place on Monday, March 27, 2023, at 20:00 IST. This contest will be an **ICPC-styled** contest to provide an exciting learning platform to showcase your CP skills. Many thanks to all the individuals who made this contest possible:

• Problem Setters: (_AbRn_, RohitRKS)

• (novaa, shreyas__09_) for testing and providing detailed feedback that improved the quality and balance of the round significantly.

• (Dev_Manus, hugewarriors) for coordinating the event!

This event will be conducted in 2 stages:

**Qualifiers**

• Date & Time: Monday, March 27, 2023, at 20:00 IST

• Participation: Individual

• Contest Link: https://www.codechef.com/CDFT2023

• Registration Link: http://shorturl.at/frIMN

• The top 100 Participants willing to come for the onsite finals will qualify for the final round.

**Finals**

• Date: Friday, April 14, 2023

• Participation: Individual

• Mode: Onsite, the Top 100 participants from online qualifiers will be invited for onsite finals at AIT, Pune Campus.

• Participants reporting for onsite finals will have four events **CodeRed**, **Bug-Off**, **Retracer**, and **Short-Code** to take part in.

**Onsite Final Events**:

◉ Codered: Competitive Programming event

◉ Retracer: Figuring out the code using only the input and output files

◉ Bug-Off: Debug the Code

◉ Short-Code: Smaller Code Wins!!

**Prizes and Goodies**

**Qualifiers**

• The top 25 Indian participants will receive goodies, delivered to their addresses.

• 5 Random Indian participants from the top 300 will receive goodies, delivered to their addresses.

• 5 Random students from AIT will receive goodies.

**Finals**

• All the onsite finalists will receive a CoDeft **T-shirt + Goodies**

• Event Winner, Runner Up

• CodeRed: 12,000/- INR and 8,000/- INR

• Retracer: 6,000/- INR and 4,000/- INR

• Bug-Off: 6,000/- INR and 4,000/- INR

• Short-Code: 6,000/- INR and 4,000/- INR

• Goodies for the top 7 participants on the leaderboard for all three events separately.

Don't forget to **register** to be eligible for **goodies and prizes** — http://shorturl.at/frIMN

Join Discord Server for regular updates — https://discord.gg/dCSUUmRBBM

Auto comment: topic has been updated by RohitRKS (previous revision, new revision, compare).Reach ++

Good Luck !!

Excited !!

As a participant, Wish you Luck !!

All the best to every participant

What about international participants? Are they allowed to participate onsite if they qualify? If yes how will they join onsite? I mean by their own financing or there are any sponsors?

no, you have to be on your own financing

GoodiesYooohooo... All the best guys :)Reach++

Reach++

CFBR

I appreciate that you are sending reminders for the contest. But please use bcc instead of cc while sending the emails.

Ok will look into it from next time...

Will the problems be sorted by their difficulties?

How to solve SUMPROD? I know some n*k solutions passed; how to do it faster, though?

You can use D&C + FFT. You need the coefficient of $$$x^k$$$ in $$$(1 + a[0]x)(1 + a[1]x)...(1 + a[n-1]x)$$$.

n*k solution give tle to me , i dont know why

You can try doing space optimization in your dp.

Yus I did that , i create 2 dps and swap the old dp with new dp

475D - CGCDSSQ similar question to GCDSUBARR

How to solve

GCD on Subarrays?I can think of O(N^2 * Log(max(A[i])) solution;

Edit1: If there's a different approach than above.

Since gcd is a non increasing function we can binary search to calculate count of all subarrays starting at every particular index i.

Also due to tight TL and gcd being an idempotent function you should be using sparse table instead of segment trees for faster computation.

If you take all the gcd ending at arr[i] there will be atmost log(n) different gcd possible. So for finding all the gcd ending at (i+1) you can just do gcd(arr[i+1],ending at i) log(n) time.

Thank you guys! I don't know the Segment Tree or Sparse Table but the other solution as written in the above editorial (their 2nd solution) and by sobhagyaSD makes sense to me. Thank you!

Edit 1: Sparse

TablebutCan someone share an approach for the problems today?

I can't seem to look into others people's submissions!

We will publish the editorials of the contest today. Thank you

Where to find editorial for problems ?

Can you please move problems to practice section. It is showing an error when trying to submit in practice.

Sorry for the inconvenience, you can practise the problems now.

No problem,thanks i finally got ac for the SOP problem

Can anyone tell me how to solve the "MAXIMISING SUM" ! I don't know whether I am missing a case or unable to understand the question statement properly I am doing this : Link

Elements can be negative too therefore sometimes it will be better to not choose any or choose only 1 element.

consider the case when a,b,c,d are negative values, then you should choose none

He did pushed 0 at first ig, but the code was messy so can't guarantee it.

Also arunavabanerjee2018, we can't see your submissions, so better share a pastebin/gist link or paste a better formatted version of your code.

I can't submit the code now, but I think endl is the mistake :'-)

It should work.

can you share your code

CodeI think endl was my mistake

you can do like a b c d max({a , b ,c ,d ,0ll, a +c , b +d ,a +d})

When will the problems be available for submission in the practice section?

The practice problems will be available soon. Thank you for your patience.

THRIARR was already used in one of your past contests link. Not sure if the solution was leaked.. Could you post the solutions or atleast make submissions public? Thank you!

We will post the solutions in a short time.

How to solve zero tree?

Sorry, for the delay. We will publish editorial today itself.

still waiting :)

BASTI KA HASTI BRO CODEFT AARELE KALTI LO,BOMBAY ME BACHAYA BACHI KO,PTOWN PTOWN

Any updates, will there be an offline event and who are the finalist?