The idea is that we calc each next number manually; we know that next number is one of 3 possible routes: to increase 1st expo, 2nd or 3rd by 1. So we calc all 3 numbers (what they will become with increased expo and pick minimal), we increase expos of taken step, save number and repeat all again.

46 comparisions to encode 'Z' :)

The task stated that you're given a valid number and examples also shown that you are in fact is getting only a Number. By converting it to a String in your code you introduced an issue about different separators and now you're solving it :)

Test is broken, always fails with "Fakes not made by the lock itself should not pass" for different solutions i tried.