Hello Codeforces,

I invite you to participate in the **ICPC Amritapuri Practice Session #3** hosted on **CodeDrills** in coordination with **ICPC Amritapuri**. It would be a **1.5 hours** long contest having **4 problems** of varying difficulty.

**Contest Details**

- Contest Link — https://codedrills.io/contests/amrita-icpc-practice-session-3
- Date —
**14 Feb 2021**, Sunday - Start Time —
**20:30 IST** - Duration —
**1.5 Hours** - Will follow standard ICPC scoring system (20 minutes penalty and 1 point per problem)

**Registration**

You will need an account on CodeDrills to participate in the contest. If you have not signed up on CodeDrills yet, do so here. If you already have an account, no extra registration is required.

**Prizes**

- Cash prizes of INR 35000 for top 15 ranks.
- 1st Place — INR 5000
- 2nd, 3rd Places — INR 4000 each
- 4th, 5th, 6th Places — INR 3000 each
- 7th, 8th, 9th, 10th Places — INR 2000 each
- 11th, 12th, 13th, 14th, 15th Places — INR 1000 each
- Only Indian participants are eligible for prizes but everyone can participate.

**Special News**

- We have launched profile feature. Access it here — https://codedrills.io/profile. Please add your Codeforces/Codechef account and verify it.
- We have launched CodeDrills Campus Chapter Program, to be a part of it, please have a look here — https://codedrills.io/campus-chapter-program.

I hope you will enjoy solving the problems. Any feedback is appreciated after the contest.

Good Luck & Have Fun!

Hope to see you participating!!

**UPD1**: Editorial/solution outlines are out! Check them under Editorial tab for a particular problem!

**UPD2**: We have also received some feedback on penalty rules of the contest and will be looking to tweak them in future contests.

Man, 14th Feb is Valentine's day. We all will be solving problems instead of ...

We thought of large community of programmers who think their valentine is none other than code! So that they can spend some quality time with their valentine!

I was just joking man. It's a great initiative!

Reminder: Contest starts in around 30 minutes!

Auto comment: topic has been updated by Vichitr (previous revision, new revision, compare).Anyone got AC using NTT in the last problem

Unique Strings? When I did NTT ( which runs in $$$O(n \cdot logn)$$$) I got TLE. But when I did simple brute force multiplication of polynomials (which runs in $$$O(n ^ 2)$$$ ), I got AC within $$$80 \text{ms}$$$. Ofcourse, factor of $$$26$$$ will be there in both the cases.I AC'd with FFT-Mod in 80ms: Code

My code is similar like yours , still it's giving WA. link

I would advise both you and Jaydeep999997 to test your polynomial multiplication code on Library Checker. For now, yours gets WA and his gets RE on several cases there.

Thanks! I also did the same thing. Initially I kept FFT_CUTOFF as $$$150$$$ but got TLE (link), after changing it to $$$300$$$ I got AC (link) .

Can you please share your brute force sol link too.

Link

I will request you to clear One more doubt. this problem is same but here we don't have to explicitly find the n-tuples for Integer solution of $$$x_1+x_2+...+x_n=k$$$. and complexity here is $$$O(nk)$$$ like $$$O(26*k)$$$ (if only 26 boys like alphabets in unique string task) but for

Unique Stringit's $$$O(26*k^2)$$$. So the question is — Is this increase in complexity because of we are interested in the n-tuples explicitly i.e. value corresponding to each $$$x_i$$$ also. Or is there any way to solve Unique string in $$$O(26*k)$$$? IceKnight1093 or Jaydeep999997 or anyone pleaseWe originally had the problem with large constraints, $$$n = 10^5$$$ but later, we decreased it to pass $$$O(n^2)$$$ dp solutions. Hence $$$O(n^2)$$$ polynomial multiplication also passed in given TL.

https://ideone.com/InFQ4d this is my submission for problem c city divisions. My approach is of O(n^6) by using dp can anyone please help me understand what am i doing wrong ?

Can anyone share their solution for city division using entirely iterative dp?

Any idea when will the official ICPC rounds will take place in India, this time it has been a long delay and when will the registrations start?

Official announcement is out now! Link — https://www.amrita.edu/icpc21

Amrita will host the 2020 Regional contest that was cancelled because of the pandemic, in May 2021. Both the Preliminary Round & Regional Round will be held online on CODEDRILLS platform.

Preliminary Round: May 16; 2.5 hours duration. Registration to start on March 1 on Baylor System and ends on April 30. There is no Registration fee to participating in the Preliminary Online Round.

Regional Round: May 30; 5 hours duration. Teams will be promoted after the Preliminary Online Round.

Well, this is a great news to me.

But, Do I have to be happy about it or not : Both the Preliminary Round & Regional Round will be held "

online" on CODEDRILLS platform.That was just the initial announcement. They may or may not keep it onsite depending on the pandemic situation. Let us hope for the best.