In this paper we report our experience, related to the online training for the
Italian and International Olympiads in Informatics. We developed an interactive online
system, based on CMS, the grading system used in several major programming contests
including the International Olympiads in Informatics (IOI), and used it in three distinct
context: training students for the Italian Olympiads in Informatics (OII), training teachers
in order to be able to assist students for the OII, and training the Italian team for the
IOI. The system, that is freely available, proved to be a game changer for the whole italian
olympiads in informatics ecosystem: in one year, we almost doubled the participation to
OII, from 13k to 21k secondary school students.
The system is developed basing on the Contest Management System (CMS, http://cms-
dev.github.io/), so it is highly available to extensions supporting, for instance, the pro-
duction of feedback on problems solutions submitted by trainees. The system is also freely
available, with the idea of allowing for support to alternative necessities and developmen
