Using CMS as an online judge server

[qnighy]

I think CMS is not suitable for an online judge server now. However, since a few years ago I have wanted to use it as a hybrid contest/online judge server. One reason is task preparation: the cost of task preparation would be halved if we could use exactly the same task formats in both contests and online judges. What one have to do would be just letting tasks go to the archive and people would be free to submit to the tasks.

I suppose that CMS is getting closer to that situation. Users are decoupled from contests. And @akmohtashami's nice analysis mode patch #640, if it is merged, might also be used as online judge mode. Other things to do might include:

• Allow users to submit to tasks in analysis mode even when the user is not in the contest.
• Show multiple contests at once.
• Registration form. We (the Japanese OI team) have used such a patch in house.

How do you think about that? Is it too general for the aim of CMS? Or is it worth doing?

[wil93]

For the "Show multiple contests at once" point, there are already two PRs open:

• [x] #545 -- this makes EvaluationService process all contests simultaneously (no more -c flag)
• [x] #594 -- this makes ContestWebServer able to show (and handle) all contests simultaneously (now the -c flag is optional: when specified, CWS will use the old behavior).

I hope those PRs will be accepted soon :smile:

I'm sad, though, because the second one is already too old to be merged directly (smaller new PRs have introduced conflicting changes) and I really don't look forward to rebasing it :cry:

[wil93]

Update: the mentioned PRs are now merged.

To improve towards the "online judge" use case, at least these new PRs should be merged:

• [ ] #646 -- to let users participate without need to manually add a "participation" for them
• [x] #746 -- to manage "analysis mode" of contests
• [ ] #748 -- infinite contests

Edit from @stefano-maggiolo: expanded list