One of my ex-students (now at uni studying Physics) has discovered that not knowing how to program is quite a disability for a physicist.

So she's asked me to teach her, and in my travels I've found Project Euler, which seems a fun way of getting the grey cells functioning.

The first two problems were trivial, and my first naive stab (five minutes) at the third yielded a solution that, while logically sound for small inputs, didn't scale well enough for the large one specified, so when I get a chance to have another go at it, it looks to prove an interesting exercise in optimisation. I imagine the later problems get harder quite quickly.

Has anyone else tried Project Euler? How far did you get and remain interested?