why not?

That's O(n), and so it makes the code O(n^2), which is not desirable.

Mmmh... I did some checks I it seems you're actually right. How weird JS is, compared to python or java... (just started JS 1 week ago, still unraveling a lot of weird stuffs x) )
Maybe related to its JIT compilation?

Yours is worse, on long strings... ;p (you use string concatenation and you compute the indexes on each iterations. I don't). Mine would need to get rid of the set, I guess, to become pleny efficient.

mmmh... then I don't understand what your problem was. Anyway...

... :o

na, what I'm saying is that you should print the data you need to know to the console... print, console.log, System.out.println, whatever your language uses for that...

(wonderfully wondering, now... 8) )

not an issue, a question.

• Issue: problem in the kata itself (description, wrong tests, wrong internal solution...)
• Suggestions: well, I guess that part is clear
• Question anything else that is related to you having a problem solving a kata -> that's you, currently.

When you post issues:

• provide ALL the useful information:
  • language
  • input
  • outputs (actual expected) when relevant
  • error message when relevant
• check, DOUBLE check that this IS an issue, meaning that the problem is in the kata itself and not in your code. If it's in your code, post rather a question
• if you pass this step, you still have to prove/explain what the issue is (and if you can provide fixes, it's even better)

When you post a question: well, most of the above apply too x)

If you post code, use proper github markdown, so that it's readable.

But now I'm wondering...: how did you manage to get to 2 kyu and 500 katas without even knwoning the very basics of debugging...!??
=> print to the console

Last thing: this kata is way overranked, so you'll have to find your way on your own: Things won't be made clearer in the description.

cheers

see here