We are happy to introduce a rating system for Codechef based on the contests we have every month. In brief, the rating system will have the following features.
1. Every user will have a rating. The user with the highest rating will be ranked 1, the user with the next highest rating will be ranked 2 and so on.
2. The ratings for the users will depend only on how they perform in the contests and not how they perform in the practice section.
3. Every contest problem will get a particular value based on the number of users solving that problem. The maximum value for a problem tends to the value 5 and the minimum value for a problem tends to 1. So, every user is guaranteed at-least 1 point for solving a problem. The selection of the value 5 was to give sufficient room for the top performers to increase their rating. Selection of a smaller range of values would let those participants solving only easy problems and participating frequently overtake those not participating frequently but performing exceptionally well when they do. Suppose the total number of users who have solved a particular problem is PS and the total number of users who have participated in the contest is TS, then the point value for a particular problem is 5 – 4*PS/TS. So, if there are more users successfully solving a problem, it’s value will be less and vice versa. The Challenge problem point value is calculated by taking the product of the score for the challenge problem with the maximum rating a contest problem can have i.e 5.
4. Suppose a user has solved P binary problems and 1 challenge problem and at the end of the contest, these problems have the values V1, V2, .. ,Vp then the total rating score S of the user for that contest will be V1+V2+…+Vp + 5 * (score of the user for the challenge problem).
5. The new rating of the user will be old_rating+S.
Also, every user’s profile page will now have a rating graph along with the current rating and rank. Your feedback in this regard is much appreciated 🙂