Not just vintage games like Doom. Most modern calculators/[cg]pus will use some form of lookup tables for transcendentals. There are performant alternatives when lookup is not available (in memory limited applications like old microcontrollers), but if you have the option, it would make no sense to go for the slower more complicated algorithm. Lookup tables aren't just limited to calculating transcendentals, they are ubiquitous across software and hardware.

That's what was used in Doom (yes, original Doom 1). Instead of calculating sin/cos they had a table.

It is possible to support scala directly? Considering you are supporting already Java (and so you must have a JVM running somewhere) it should be easy

Support python 3.4 please.

Well, one can do it manually, but such a feature would be nice.
Or maybe, some sort of "favourite" code collection (that user favourites as he goes) that you can see like a summary in your own profile.

I think this should be considered cheating.

Print out Best practive vs. Own solution.

Offer an option to print out the own solution vs the BestPractice / Most clever solution.
It would be great for beginners to hang it on a wall and get reminded constantly that there are better ways to solve the same problems.

Also make sure that the color coding is integrated and that its without the black boxes.
To save ink.

Im doing it right now, but its cumbersome to cope/paste it to word, all the formatting goes lost in the process.