Carrot

 

A browser extension to enhance Codeforces ranklists

For an active contest
Carrot calculates rating changes according the current standings when you open the ranklist, and displays them in a new column. Carrot also adds a column showing the delta required to rank up. The delta calculation is done in real time.

For a finished contest
Carrot displays the final deltas of each contestant in a new column and shows their rank change, if any, in an adjacent column.

For both active and finished contests, Carrot displays a column for performance, the rating at which the delta would be zero.

FAQ

How does it work?

Carrot runs in the browser and fetches all the data it needs from the Codeforces API.
It then calculates the rating changes following the algorithm published by Mike Mirzayanov here, slightly modified so that it matches the current CF algorithm. This updated algorithm is adapted from TLE.

Is this better than CF-Predictor?

Not necessarily. The CF-Predictor extension communicates with a server, while Carrot fetches data and performs all calculations in the browser. So the network usage is significantly lower for CF-Predictor. However, Carrot is 100% accurate (see #18), it works in real time, and it shows performance values.

How is Carrot fast enough to calculate rating changes of every contestant in real time?

FFT. The answer is always FFT.

I found a bug or would like to request a feature.

Reports are welcome, please open an issue.