Greeting Codeforces Community

RECursion, the coding community of NIT Durgapur, is glad to invite you to RECode 12.0 which will be held on 27 April at 21:00 IST. The contest will be rated for both divisions.

The problems are prepared by me rishup_nitdgp. There will be 7 problems for both the divisions and 2.5 hours to solve them.

Thanks to Sachin Yadav, Taranpreet Singh and Jatin Yadav for testing the problems and their valuable suggestions to enhance the test cases. We also present our special thanks to the CodeChef Community to help us to prepare the contest and for the astonishing platform.

Prizes:

• For Indian participants:

  • Top 10 from the rank list will receive 300 laddus.

• For Global participants:

  • Top 10 from the rank list will receive 300 laddus.

• For combined participants:

  • Random Laddus to any 5 users: 200 laddus.
  • First to solve each problem individually: 100 laddus.
  • Country-wise participation: Top 10, 20, and 30 will get 30, 40, and 50 laddus as per participation.
  • Country-wise performance: 200, 250, 300 laddus as per performance.

So buckle up to increase your ratings and raise on the Leaderboard. Amidst this chaos when everything is under lockdown, let us not waste this time, rather keep the spirit of coding within us alive.

Stay Home, Stay Safe, and Keep Coding.

UPD: The editorials can be found here.

Hello Codeforces,

Are you the kind of person who spends sleepless nights learning new algorithms. Do you use data structures as if it's your pen? And do you speak code?

It's time to hone your problem-solving skills. Get ready with your laptops and put your brains in use cause this Aarohan 2020, we bring you again our very own coding challenge Decathlon where you will be put to test against some of the best coders. So bring out the gladiator within you and put the destruction mode on 9th February 2020 at 10 pm.

The contest will be held on the Codechef platform.

The contest consists of 6 problems to be solved in 2:15 hours.

Setter — Ritesh Gupta
Tester — Subhadeep Chandra

There are exciting prizes for winners:
- Overall First Prize: Rs 3000/-
- Overall Second Prize: Rs 2000/-
- Overall Third Prize: Rs 1500/-
- Top Three from Ranklist will get CodeChef Laddus.
- Certificate and other exciting fest goodies.

#Aarohan2020
#TeamAavishkar

Hello Codeforces.

RECursion, the coding community of NIT Durgapur, is organizing coding contest RECode 9.0 which will be held on 15 November at 19:30 IST. We invite you all to participate in the contest.

The contest will be held on the Codechef platform.

The contest consists of 6 problems to be solved in 2 hours.

There are exciting prizes for winners:
- Overall First Prize: Amazon Gift Voucher worth Rs 3000/-
- First from NIT Durgapur: Amazon Gift Voucher worth Rs 2000/-
- First of Second year(NIT Durgapur): Exciting Goodies.
- First of First Year(NIT Durgapur): Exciting Goodies.
- Top Three from Ranklist will get CodeChef Laddus.

You can take a look at our previous contests here:
CodeKnight
RECode 2.0
RECode 4.0
Alohomora
RECode 5.0
RECode 6.0

Hello Codeforces

I like to create problems and I want to hear some of your suggestions in order to improve my methods. I am describing the way I start preparing a problem. It is divided into two phases as mentioned below.

Creating a Problem :

1. Think about the data structure(like an array, string, tree, etc...) on which I want to build a problem.
2. Explore some fresh ideas or use some previous idea in a different way.
3. Do mathematical modeling of the problem and try to find a brute force solution.
4. Start to go deep and find an optimized solution in terms of time complexity and space complexity which solves the problem less than brute force solution.
5. Find a mathematical proof to the solution. If I find proof then replace brute force solution with it and repeat the process 4 until I reach the best solution.
6. Adjust the constraints according to my optimized solution and examine the corner case.
7. Prepare a statement for it.
8. I build test-case in such a way that all the cases are covered.

Test-Case Generator :

1. I am using C++ for generating test-cases.
2. I used a single file which first generates input and then output.
3. I select the number of input files and number of test-cases in each file.
4. There are a total of three types of test-cases -

• Hand-made -> to include corner cases.
• Small -> to examine the solution's correctness using a brute force solution.
• Large -> to cover the test-cases which gives time-limit-exceeded.

1. Generate input and output. This differs for different problems.

Difficulties :

1. Originality — Let suppose you making a problem or working on some idea and somehow you find out that the problem already exists but this is not the challenge, the challenge is if you find out after the contest or some contestant complain about it.
2. Weak Test-Cases — This is a very major issue. Many times you write a test-case for a problem but it is not that much strong that you are willing and might be you left some of the good test-cases, that gives some issues like AC on the wrong submission, AC on unoptimized code etc.
3. Less Optimised Author Solution — Sometimes the author solution has more time complexity than the contestants' solution. This does not generally occur but causes issues.
4. Likeness — In general we make a problem and we do not know whether this problem is liked by the majority of people or not. Or they found some educational in the problem.
5. Difficulty — Sometimes it happened what is easy for us might be tough for others and vice versa. Also, the difficulty level we assign to some problem is far away from what comes after the contest based on submissions.

I just want to know how to overcome these difficulties.

If all works fine then the problem is prepared and now the time to give it to someone for testing from where you get feedback and improve either problem statement or generator code.

The post Way of problemssetting is very useful for me to improve my problem setting skills. I am attaching one of the recent problems which I made in RECode 5.0 contest hosted by RECursion NITDgp.

Problem Link
Test-Case Generator Link
Solution Link

Thanks in advance.

Hello Codeforces.

RECursion, the coding community of NIT Durgapur, is organizing coding contest RECode 5.0 which will be held on 2 February at 14:00 IST. We invite you all to participate in the contest.

The contest will be held on Hackerrank platform. The contest consists of 6 problems to be solved in 2 hours.

There are exciting prizes for winners:
- CloudSploit Premium Coupons(total worth $800) for top 2 winners.
- CloudSploit Basic Coupons(total worth $1600) for top 100 participants.

CloudSploit is a security and configuration scanner that can detect hundreds of threats in your AWS account. It is open-source software with free and paid hosted options.

You can take a look at our previous contests here:
CodeKnight
RECode 2.0
RECode 4.0
Alohomora

Hello Codeforces.

RECursion, the coding community of NIT Durgapur, is organizing an ACM-ICPC style based contest ALOHOMORA. The contest will be held in two stages, online round and onsite round. The online round will be held on 19 January at 21:30 IST.

The contest will be held on Codechef platform. There will be 7 problems which are to be solved in 2 hours.

Participants need to register themselves in teams of max 2 members. Top 5 teams from NIT Durgapur and Top 5 teams from other institutions in the online round will qualify for the onsite round. The onsite round will be held on 2nd February 2019. There are cash prizes and goodies for top 5 winners at onsite round.

We invite you all to participate in the event.

Hello Codeforces.

RECursion, the coding community of NIT Durgapur, is organizing coding contest RECode 4.0 which will be held on 13 November at 16:00 UTC. We invite you all to participate in the contest.

The contest will be held on Hackerrank platform. The contest consists of 6 problems to be solved in 2 hours. There are exciting prizes for overall winner and college winner.

The RECode 4.0 is over, Ranklist is as follows:

1. Teo Moroianu
2. Jeffrey Ho
3. Kerim Kocekow
4. Uwi Tenpen
5. Farhod Farmon
6. Teimurazi Toloraia
7. Saharsh Luthra
8. abishek a
9. Nishant Arya Kumawat
10. Victor Forbes

UPD : Editorials