Bad. in this map, you need to write an analog of the xor operator and not use it

Yes

I'm still learning time complexity, this is O(n^2) right?

Please use spoiler flag next time.

sorry

Please use spoiler flag next time.

it's a Python 2 function that no longer exists in Python 3

I copied the solution, but it doesn't work.
What does unichr do? This function is not defined

This solution was written in Python 2, where the division operator had a different behaviour.

how this solution was test-accepted? if there is an typeerror of non integer index

It is "+1" at the end because the slice operator (:) does not include the last position. So if you print(s[0:1]) it would only print the character at position 0.