The CTU Open Contest is a preparation for the CERC. It is a local contest held at CTU Prague and its main goal is to choose the team representing CTU in Central European Regional Contest. To make the competition more interesting, the Contest is open for any Czech university. The universities from the Czech Republic are not required to participate in CTU Open Contest. But it is strongly recommended, because the participants of CTU Open will be preferred in CERC if there are too many teams applied. Besides, it is a very good preparation. The Contest Rules for CTU Open Contest are the same as CERC Rules. The only exception is that the contest language is Czech.
Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.
→ Practice?
Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.