At the onset of this new year we are gifting ourselves a new calendar on CodeChef to keep everyone updated on important programming events. If you think we have missed any event please comment on the page to get them added to the calendar.
We’re finally in the middle of Christmas season! A time for fun and joy and also giving each other lots and lots of presents! Our chef is always excited at this time of the year and cannot wait to reveal his gift for you all.
Are you all ready? *drum roll* With the new year will also come into place our brand new ‘Short Contest Ratings’!
Check out the salient features of our very exciting rating system :-
1. The ratings will take into account COOK01, COOK02, COOK04 and COOK05. COOK03 will not be considered as it was a team based contest.
2. A player will be rated (awarded rating points) in a contest if she has made at least one submission in the contest. If someone doesn’t make even a single submission in the contest then her rating will not change after that contest. (note that it may bring down her rankings).
3. It will be a seed based rating system modeled on the ELO rating. Reference – http://people.ksp.sk/~misof/publications/2009thesis.pdf page – 22.
4. The rating algorithm is a function which takes 2 inputs in the form of Ratings before this contest and Ranks in this contest and gives the final Rating as output. If a contestant participates for the first time in a contest then her previous rating is taken as some default value (say 1000).
5. Mathematical details of the algorithm are described here in brief :-
First for each pair of players (A,B) we calculate the probability of A defeating B and vice versa based on the ELO formula. Then for every player we calculate the sum of probability of defeating other players.
P[B, A(i)] = probability that B defeats A(i).
total[B] = summation of P[B][A(i)] over all A(i).
n = number_of_participants.
The expected rank of a player B in a contest,
E[B] = n – total[B].
We define regular factor for contestant B,
Regular_factor[B] = E[B] – Rank[B].
We have also added a bonus factor so that we can reward extra points to players who have been ranked higher in the contest.
bonus_factor[B] = n/rank[B].
Then for each participating contestant her rating is modified as follows:
New rating[B] = rating[B] + k * regular_factor[B] + m * bonus_factor[B].
Here k and m are constants to give appropriate weight to both the factors.”
Do send in your feedback and let us know what you think of this new rating system for short contests. We hope you are as excited about it as we are!
Best wishes for the new year to you all!
The December 2010 CookOff, our fifth short contest and our final short contest for the year 2010 has now ended. The competition began with a bang as 3 corect submissions arrived withing just 9 minutes.
We would love to to thank our fantastic cooks this night, Zac Friggstad and Rajiv Aggarwal, our awesome problem setter, tester and moderators.
Here are the top 10 best performers of the December Cook-Off:
Take a look at the contest rankings here.
|Length of Contest||Unique Participants||Total Number of Submissions||User who have solved at least one problem|
|Rest of World||47|
Congratulations guys! We look forward to seeing all of you participating in the January 2010 Challenge that begins with the new year!
Check out the contest problem editorials here.
If there is anything you would like to let us know regarding this contest then do let us know by either commenting below this blog post or by sending in an email to firstname.lastname@example.org.
P.S. Winners of the contest will be contacted on Monday (20th December).
The December 2010 Challenge is now over. The contest started with a bang and it seemed very easy with participants solving 4 out of the 6 problems on the first day itself. But things didn’t look quite easy as they seemed on day 1, the other 2 problems took almost 6 days to solve.
Lets look at some Stats and then move on to see the final winners list.
|Length of Contest||Unique Visitors||Unique Participants||Total Number of Submissions||User who have solved at least one problem|
|Country||Total Participants||Average Score per User|
|Rest of World||141||1.53|
Winners list for the December 2010 Contest:
UPDATE 21 Dec 2010: Due to certain malpractices that have been identified, 2 contestants have been disqualified and the winners list has been updated.
01. Suhash Venkatesh (winner of prize money Rs. 12000)
02. Rudradev Basak (winner of prize money Rs. 8000)
03. Nikhil Garg
04. Utkarsh Lath
05. Pradeep George Mathias
05. Tasnim Khan
08. Amit Karmakar
09. Gunjan Sharma
10. Pratik Tandel
11. Mahesh Chandra Sharma
12. Anish Shankar
12. Surendra Meena
12. Uday Jalan
16. Shivmitra Mishra
17. Smit Hinsu
18. Paresh Verma
01. Philip Pronin (winner of prize money $400)
02. Burdakov Daniel (winner of prize money $300)
03. Roman Rizvanov
05. Wu Yin
06. Tomek Czajka
07. Lai Luhang
08. Mark Greve
09. Ivan Mistreanu
Congratulations to all.
If you haven’t yet checked out the editorials of the problems to this month’s contest please do so here.
We are running a 2.5 hours Cook-Off that is scheduled for 19th December at 21:30 IST
If there is anything that you would like to let us know then do comment on this blog post or send in an email to email@example.com
We have introduced a new challenge tab in the practice section wherein all the challenge problems will be listed. This enables you to find all the challenge problems in a single place without browsing through the other categories. All the challenge problems that belonged to the previous contests have also been added to this area.