That sounds like it might work. I don't think those details were presented in the survey or this forum thread, so it was unclear what was being discussed. And I only offered mild criticism for what it vaguely sounded like. Now with the details, I do have a few hesitations:
a) It seems like it might help cheaters a little, by clearly identifying which problems are known to have published solutions and which are not.
b) It seems kind of unnecessary, but I don't know. The current ranking system still gives a pretty good indication of where people are in relation to each other, doesn't it? I'm just not sure if we gain a lot by doing it that way.
Well, "So people would have limited time to solve some unspoiled problems" is really the point I was making. That seems to be a big feature of live contests in general. And it also seems to apply to the proposed idea of adding a new problem set.
For comparison, Project Euler was the first problem solving contest site that I participated in, before I knew SPOJ existed. It was clear to me while participating on that site that the way to prove you were not a cheater was to get on the list of fastest solvers for several problems, if you could. (Of course, trying to solve those problems as fast is possible is also a fun and hard challenge, regardless of whether there are any cheaters there or not.)
With a contest like ALGOLIGA, aside from being interesting in itself, cheating could be monitored more closely, and then after deadline the results get locked in permanently, so there is no possibility to have the points diluted by cheaters at some future date. After deadline, problems could be added to main SPOJ without any official solutions posted, and treated like other classical problems.
We know that there are many honest problem solvers on SPOJ. (For evidence, just look at the status page and see how many non-ACs are getting submitted all the time.) But some may worry that their rank will not be taken very seriously because of the effect of cheaters, and that it may not be easy to tell whether or not you are one of them. While I think the main ranking is still a decently meaningful metric, having another contest with rounds and deadlines might be a nice alternative option for those who would be interested. (And maybe a way to generate some extra excitement in the SPOJ community, and encourage new, original and high quality problems to be published.)
It's just an idea that seemed to apply to the discussion. It doesn't really have to be considered in the light of cheating. It is really a separate idea that can stand by itself.
And I know it would take a lot of work to organise such a contest. I'm not suggesting admins would need to devote any time to it (besides possibly making announcements of new rounds coming up). It would only be an option if we happened to have enough skilled problem setters who wanted to see the project happen.
That's good to know. My knowledge of other programming contests is generally quite limited (aside from knowing their names).
Maybe the idea of a contest like ALGOLIGA but in English (with a similar connection to main SPOJ that ALGOLIGA has to Polish SPOJ) is redundant considering other contests like CodeForces, TopCoder, Google Code Jam, etc. I hadn't considered that much. I guess it would require looking at a lot of details, to see if there was anything really new to offer. (Although maybe it would be worth doing even if feels a little redundant, for various reasons like the effect on the community.)