Contest Rating System


What is rating?

hihoCoder uses rating system based on the Elo Rating System to evaluate user’s ability of algorithm and problem solving. In hihoCoder, each user has his own rating, this rating represents the performance of this user in hihoCoder’s monthly competition.

In fact, you can use this rating to calculate the probability of A wins B when they participate the same hihoCoder’s monthly competition. When A’s rating is RA, and B’s rating is RB, then this percentage will be:

That is to say, if A’s rating is 100 points greater than B’s, then the chance to win of A is 64%, and when this difference becomes 200 points, the chance become 76%.

How is rating changes?

When a new participant comes to hihoCoder Rating System, he will get 1200 points as his initial rating.

hihoCoder will hold monthly competition, at then end of each competition we will changes participants’ rating according to the result of competition as we describe below.

For a participant, we will calculate his expected ranking according to his rating and other participants’ rating.

Then compare to his real Rank (RRank), then his rating will be modified like this:

The K we use here is decided by the current rating of participant and competitions his has took part in.

Participate less than 10 times, and rating is under 2100 K=32
Participate no less than 10 times, and rating is under 2100 K=24
Rating is above or equal to 2100. K=16

How is rating useful?

First of all, there is no doubt that rating represents your personal ability, it represents the grade you achieved in our HihoCoder monthly competition!

Also, rating will color your name with all kinds of colors, and you may unlock medals when you reach some height. What’s more is that your can compete to your friends to see who’s the best problem solver now!