Successful Conclusion of Perplexed! Main Contest

Posted on March 13, 2011 by alok

We are truly overwhelmed with the response and participation of the contestants during Perplexed main round. We heartily thanks to all the participants for making this event successful. Perplexed! is such a learning platform which explores the dimensions of C language. Problems are so chosen and constrained such that for each problem there are many ways to solve it, but the best method is that with least constraints that actually tries for a specific concept of language C to be implemented.

The main event of Perplexed! was started on 1800 Hrs IST on 11th March and successfully concluded with people fighting for the best code till the last moment on 0200 Hrs IST on 12th March, 2011.

A total of 1621 participants from 49 countries participated and 7552 submissions were received for 7 problems. The scoreboard and results for this very event are available on scoreboard. You can also check out the correct solutions of the other participants in the contest on respective problem rank pages. Explanation for each problem is available on their respective problem pages.

We would like to congratulate cmds from Volgograd State Technical University, Russia for standing first in the competition. He was followed by al13n321 from Tomsk State University, Russia and dolphinigle from Institut Teknologi Bandng, Indonesia. Congratulations to them for their performance and our heartiest consolation to all for participating. Other prize winners have been declared on Perplexed!. We hope Perplexed! comes to be a great platform for learning C concepts for programmers around the globe.

Our algorithm intensive challenge Manthan is scheduled to be held on 13th March, 2200 Hrs IST. For more information visit Manthan.

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Tips and Tricks for Perplexed!

Posted on March 2, 2011 by alok

Congrats to all participants for making the Perplexed Trial Round successful and thanks for your patience and enthusiasm during the contest.

Perplexed does not aim to test your knowledge about challenging algorithms but a platform to learn about the dimensions of C language and honor the best in this regard.
A problem asked in Perplexed is simple and can be solved through various ways. You need to submit codes which suit most according to given constraints.

There are some tips which can be useful during Perplexed Main Contest:

  1. Make a solution that works first. Then try to improve it without using the constrained keywords and operators.
  2. Do not include any header files or macros. The C compiler will automatically get the header files from the standard header directory implicitly. C90 had a feature (absent of C99 and C++) called implicit function declaration: when you used a name not declared yet in a function call, the compiler behaved as if: 
    
extern int identifier();

    had been seen. That feature has been dropped from C99 and most compilers had option to warn about this even before C99 was promulgated. Read more here.

  3. Use small variable names to save total number of characters for the questions, where total number of characters are constrained.
  4. Declare variables without specifying any data type to save number of characters. According to section A7.3.2 Function Calls, Dennis Ritchie, “In the old style, parameter types are not specified. If no declaration is given for a parameter, its type is taken to be int”. C still supports this old style.
    1. Global variables declared without any data type. Eg: 
      t;main(){}

    2. Arguments to main eg: 
      main(a,b){scanf(“%d%d”,&a,&b);}

  5. Sometimes number of test cases can be ignored and we read from the input data set till the end of file has been reached.
    1. One can suppress an input by using scanf(“%*d”). Here * is used to ignore the integer data retrieved from the stdin. This way one can ignore the input which is not required, like number of test cases at beginning of file. See B.1.3 Formatted Input, Dennis Ritchie
    2. scanf() returns number of data successfully read and returns -1 when end of file has been reached. This returned value can be smartly used to obtain all input data. for eg: 
      while(~scanf("%d",&a)){}

      In this, when scanf is succussful in reading, it returns some positive value. When the end of file is reached it returns -1, and ~(-1)=0, which stops the while loop.

  6. Bitwise operators are really wise. These can be used frequently as an alternative for some operations. A very good reference to this is section 7.1.3 of Art of Computer Programmiing, Vol 4 by D. E. Knuth. Some examples:
    1. To find the larger between two numbers, we have: 
      
if(b/a)
{
  a = a^b;
  b = a^b;
  a = a^b;
}

      Here, the larger value is stored in variable ‘a’. We are able to find this without using ‘’ or any temporary variable.

    2. There are alternative ways of operations using bitwise operators. eg: An operation a-b can be performed also by a+(~b+1), here we first find 2's complement of b, and then add to a.

Yes, you got it right. We want you to write a program which on compilation may generate lot of warnings but no errors!

PS: Use of whitespace characters is never restricted. So, you can always use whitespace characters and write codes which are clean and easy to read.

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Mathmania Main Event concluded successfully

Posted on February 28, 2011 by abhishek

Mathmania, an event that promised to be of highest standards, lived upto its expectation when 1559 participants from 63 countries sat in front of their computers yesterday, to code their heart out in solving mathematical problems. The Main Event which was organized at 2200 Hrs IST on 27th February, 2011, reached its successful completion when the event closed at 0300 Hrs IST on 28th February, 2011.

After successful conduction of two Trial Rounds for this event and a good enthusiastic participation from people all around the globe, we received an even better participation in the Main Event. There were in excess of 3254 submissions in problems that witnessed 252 distinct participants submitting at least one solution. Also, there were 24 professionals who shared their experience and worth among other students from 112 different colleges.

The results and solutions for the Main Event are out. Check out the scoreboard to know where you stand! We would like to congratulate rng_58, currently enrolled in University of Tokyo, Japan for standing first in the competition. He was followed by Anton Lunyov of Institute of Applied Mathematics and Mechanics, Ukraine and tourist from Gymnasium of Gomel, Belarus. Congratulations to them for their performance and our heartiest consolation to all for participating.

I would like to mention here the efforts put up by the IT-BHU participants. Due to failure of internet access for the students of IT-BHU, we decided to host the event separately for the IT guys in the local server. The event was delayed for half an hour for the IT-BHU students but the participation again was phenomenal and even the unavailability of internet access didn’t stop them or their enthusiasm. We got 198 submissions from IT-BHU students and nearly 80 participants submitting solution to at least one problem.

Perplexed! Trial round will be a 2 hour contest and is scheduled on 6th March at 2300 Hrs IST. The Main Event starts at 1800 Hrs IST on 11th March and is a 12 hour programming contest that will test all your skills and zeal as a programmer. Do participate and enjoy this coding festival.

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Trial Run of Mathmania and Perplexed! concluded successfully.

Posted on February 22, 2011 by abhishek

Mathmania, a mathematical puzzle contest, provides an opportunity to programming enthusiasts with a sound knowledge of mathematics and computational thinking to provide efficient and quick solution to a problem.

The Mathmania trial was scheduled to run at 2300 Hrs IST on February 19, 2011. We received an overwhelming participation in the Trial Round and we would like to thank all our participants for showing such eagerness and enthusiasm. We received submissions from 79 different colleges with participation from 13 countries, 7 professionals and boost of total submissions being 2433. There were 186 participants who submitted answer to at least one problem.

The results and solutions for the Trial Round are out. Check out the scoreboard to know your position if you did participate! A quick glance at the scoreboard suggests the intensity of enthusiasm and the quality of participation with the top two being international participants. Quimey from Universidad de Buenos Aires, Argentina tops the scoreboard for Trial Round. We congratulate Terrence, who is a professional from C2Micro, China and Praveen Dhanuka from Bengal Engineering and Science University, Shibpur for their 2nd and 3rd positions respectively. Keep the enthusiasm going and gear up for the main event!

Perplexed! is an online programming contest aimed to explore the depth of C language. Here, to win, keywords or tokens must be efficiently used according to the constraints provided in the problem.

Perplexed! trial was scheduled to run at 2200 Hrs IST on February 20, 2011. It received participation of 118 people from 54 different colleges and 9 countries. We also had 7 professionals submitting solutions to the problems for which we received over 1200 submissions.

Priyank Bhatnagar from MNNIT Allahabad tops the scoreboard. Congratulations to him for a great performance and consolation to others for great participation.

For those who could not participate in the Trial Round can always try their hand in the Main Event. The sole purpose for conducting this Trial Round was to make the participants aware of what’s in store for them in the Main Event.

Participate in the main event which is scheduled later this week. Mathmania is scheduled on Feb 27th evening and it promises to be of highest standards. Perplexed! is scheduled on March 11 at 1800 Hrs IST and it will be a 12 hour hustle for the participants. The trial run might have given you the feel and know-how of things to come, and you have a week’s time to compose yourself for the Main Event.

The fun is unleashed, get ready to grasp it!

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Round 1 of Ratespiel concluded successfully !!!

Posted on February 17, 2011 by mohit
Ratespiel, an online technical quiz, sponsored by IBM, provides an opportunity to technical enthusiasts to delve into the domains of Web 2.0, Service-Oriented Architecture(SOA), and Computer fundamentals.

Round 1 comprised of three sub rounds – Round 1A (Reprise), Round 1B and Round 1C. Students from all over India enthusiastically participated in all the three sub rounds. During conduction of Round 1A, Team CodeFest faced some server issues due to increased number of database connections. To tackle it, we migrated our website to a new server but were unable to conduct the contest due to some technical flaws. We regret the inconvenience caused to the participants of Round 1A. Round 1A was rescheduled as 1A(Reprise) and participants of Round 1A were given another chance to participate in any of the further rounds – 1B, 1C and 1A(Reprise).

Overall, Round 1 has been a huge success. It received participation from 215 different colleges in India. There were a total of 701 participants registered for any of the three sub-rounds of Ratespiel. The different rounds had varied participation as 1B had 93 people, 1C had 217 and 1A Reprise had 391 students.

The results and solutions for Round 1 are out. Check out the scoreboard to know where you stand! Participants who scored 40 or more have advanced to Round 2. Congratulations to them! Ankit Singh from IIT Hyderabad leads the scoreboard for Round 1 followed by Prashant Dwivedi from NIET, Greater Noida and Vikraman from Jadhavpur University, Kolkata. Keep the enthusiasm going and gear up for the next round!

For those who did not qualify for Round 2, don’t loose your heart. CodeFest aims to be a learning platform in addition to an event. We are sure that you learnt a lot during the quiz. The solutions have been made available for the purpose!

Besides, there’s  a lot more at stake. Codefest ’11 has few more events in its bag. Virtual Combat is an ongoing JAVA based robotic simulation game where Phase 1 ends on Mar 7th, Mathmania is a 5 hour mathematical puzzle contest scheduled on Feb 27th, Perplexed! is an obscure C programming contest which tests the knowledge of language C, scheduled for Mar 11th and Manthan is an algorithm intensive programming contest, scheduled for Mar 13th. Get ready to code because the fun has just started!

Participate in the trial runs scheduled for later this week to get a feel of the events. Mathmania Trial Run is scheduled on Feb 19th evening while Perplexed Trial Run is scheduled on Feb 20th evening.

Get ready because it is the time of the year when coders will have fun and newbies will learn!
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