Thank you for your fast reply :)
I'm still learning about how to recognize and subsequently reduce complexity.

see message above.

Based

[updated wiki link](https://en.wikipedia.org/wiki/Guard_(computer_science)

nice

Yes, I don't know much about Python, and I just saw that "in" for sets is O(1) so this effectively is also O(n + m).
I tried to remove the comment. But I can't.

learn your data structures, man... This is O(m+n) too...

The bad thing about this is that in the worst case the set will be equal to ind in length so this will run in O(n * m) being n length of s and m length of ind. When it can be solved in O(n + m).

hello,your solution is so easy,but how about the $n without 1?

Add random tests.

I understand that this is not meant to be an easy kata, but the part that should be challenging is creating a solution. In this case, the difficult part is understanding the instructions itself.