Amazing and clear explanation! Thanks westphalen!

Ops, when I predicted the final string size I forgot to include the hyphens while coming out with an equation for it.

It uses the mathematical understanding of a set, but you can think of it as a hashmap with only keys and no values, so unordered (can't use sort) and no duplicates.

Yeah! I just did some code breaking on VSCode an reached the same conclusion, the [...new Set(s1+s2)] seemed to weird I had to see what was happening. clever, but bad practice

can you explain both of the modulos and exactly what they are doing / why you used them? thank you.

Seeing all the crazy math people were using to solve this (math skills I can't get even close to understanding) makes me feel clever and stupid at the same time. lol

Is this worst practice than the top voted one?

I don't get it yet, but I find it sexy.

come on, that's better than many top voted ones