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A huge number of your nerve cells die every time when you wait for a rating update on Codeforces. Stop this! From now you could use this service, it calculates approximate rating changes for every contestant.


The most interested thing for you is chrome extension. It partly modifies the contest standings page and shows approximate rating changes for every contestant. You could find it here. alt tag

Also you could find more detailed information (seed, rank, expected delta, etc.) here alt tag

A project currently in beta, so predictions are not very accurate. Average mistake around 5 points, but for the contestants at the back of standings it could be greater up to a few hundreds.


Project consist of 3 main parts.

assignment path language
1 compute role CF-PredictorBackEnd Java8, Tomcat
2 web role CF-PredictorFrontEnd Java8, Tomcat
3 chrome extension CF-Predictor-Extension JavaScript (with using jQuerry)

Compute role send requests to codeforces, compute approximate rating changes and store some of them in the cache. Every cached value recomputes once a few minutes.

Web role just get rating prediction from compute role and show it in human readable view.

Currently compute & web roles runs on aws Elastic Beanstalk. Servers run only in the contest's days to prevent overusing free tier resources.

Chrome extension send request to web role, get JSON response and partly modify the contest standings page.

If you want to contribute to the project or have any questions, you could reach me by codeforces profile or email


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