This solution is at least 8 years old....

using var is a bad practice nowdays

Could you explain why it has polynomial time complexity and not quadratic O(n^2)?

I also thought about this problem.

One solution to deal with it is to remove repeated characters from the original string then test on the new string.

Tried to do this for hours didn't worked... Then I solved it with 35 line of for and if codes,
I should have ss what I wrote back then... know I dont even know what was wrong with it...

Forbidden dark magic Regex

Clever as hell; arguably not best practices, though, since most devs don't know too much Regex and wouldn't be able to debug this.

nice solution

regex bad

What's wrong with Regex? I'd say it's fine to use whatever method as long as it's natively build into javascript (not importing a library) and it's not forbidden by the author.

would break for chars like ?

if you use regex to solve 5th kyu probs on here i dont like u

Excellent solution. I think imperatively, I must spend a year in the temple with the honorable declarative monks.

Very nice !

I wanted to use recursion to solve this. I could have done it using .search() method instead of .match() (don't know which is better).