[camus2]

Frankly i've been programming for a few years i would not be able to solve the problem in 20 mins. Maybe in 3/4 hours but 20 mins no way. I could come with an idea to solve it though.

But that's a very good exercice.

> I am first year maths student at Uni Warsaw

then Math is your major discipline. Please write down how you would express the solution in a pure mathematical form.

[mike_mg]

Yeah that's a cool exercise and I try to do a lot of these!

I guess expressing it mathematically purely is already done in the code of the original solution, because in a way program == proof. If you have some time, here's a great read on this: http://www.maa.org/sites/default/files/pdf/upload_library/22...