I'm not sure that the label “fundamental” should be attached to this kata. Isn't this type of algorithm specifically linked to a particular field? So it's not fundamental in general, is it?

that's fuckin' smart <3

duration is not related here to number of lines your code have, but to number of loops it does.

Yeah, perhaps the solution is focusing on doing max one loop for each cost entry

well, this is the best solution. The only thing is now we know kyu should be related to languages ! :)

So we're OK that other 5 kyus katas are more easy ?

Were the beta-testers kind of mathematicians ? Can't find the solution to pass extra large data ^'