Warning: With enough thinking anyone can come up with a solution without knowing any specific algorithm.

its a troll kata, clearly no point doing it

that was nice

Average java enjoyer

I totally agree. Same here. Got stuck 2 hours of "finding error", I've got so pissed, so decided to write all combinations on paper, and check it. Should be no mistake. Someone needs to check Kotlin random tests.

My programm offers shorter way than results

Way too easy for 5kyu

A little tip, you could start from 3 and go i+=2 in isPrime, (checking before is the num passed is two)

There's a pattern indeed but I can't figure it out

I can't either after spending all day with 3 different algorithms...

That's not true, my solution in java uses 2 loops

Very nice kata :)

Didn't know about those substring methods

savingPerMonth instead of savingperMonth

Too easy for 6kyu