Going through the sample examns..
How important is to plan on paper the cld problem? do you dedicate around 30 minutes or more?
Tell the truth, I never mapped it out on paper. I just practiced over and over until I could recognize the kind of design pattern I would need for a given problem.
I think I spent around 20 minutes reading the prompt and planning. I have yet to see a prompt that couldn't be done with an event driven state machine so I wouldn't worry too much about architecture. My "planning" was just a really rough sketch of what general states I needed and what they did in one sentence and I only did that much because on one of my practices I got to like 3 hours and couldn't figure out how to implement a pretty important feature without changing half of what I did.