Text books. they are good for algorithms.
And for just structural type of practice, just make up algorithms for everyday tasks like... Well, a whole day or something!
And also... Study the structure of standard algorithms (like extraction, er... well other array and string type stuff).
Oh oh... A good one, construct an algorithm for babysitting a crapload of kids with all different needs...
Or one for shooting rabbits. Every fourth rabbit has to be shot, and if it is female you let it live and send it somewhere else, etc etc.
If that is the kind of thing you want, I can supply you with that kind of crap. Very much funness