Looks clever but in terms of cost:

• you have to scan the string many, many times

• each time you do parens.replace you are generating a new string.

you're overthinking this: this approach is actually very bad (think about its time complexity)

Awesome!

Great code!

I didn't know that a empty string denied is true \õ/

Thats usefull, make a lot of things easier

I had exactly the same idea, but done that a bit harder, thank you! ^_^

Clever one =)