Meet a small innovation on Codeforces — difficulties of problems (and at the same time a new widget filtering problems in the archive). For all the problems of the archive, I’ve calculated the difficulties in the scale of the rating of participants. Approximately this means that if the rating of the problem is equal to yours, then on a typical round you would solve the problem with a probability of 0.5. And, in general, if your rating is ri, and the problem rating is rj, then the problem during the round can be solved approximately with probability:
For example, if the rating of a problem is less than yours by 200, then the expected probability of solving the problem is 0.75. With a difference of 400 rating points, the probability increases to 0.9.
For convenient search of problems in the archive, you can now use a special widget:
With it, you can find not only problems that have all the chosen tags, but also which have at least one tag from the list.
A difficulty of a problem is also displayed when choosing problems in a mashup.
I hope that now you will be able to do more effective practice, and the process of making new mashups for trainings will become easier.
UPD: Have you already noticed new pop-ups about judgment verdicts of your submissions?