It is a string comparison.

The strings are all like "3:2". So it is "3" > "2" and 3 > 2. String comparison and integer comparison have the same result in this case.

Here the values are all single digits. The method fails if a string is like "12:8" because "12" < "8" and 12 > 8. However, two-digit results are not part of this kata.

Wut?. What is that ^ operator?

I'm starting with Swift and i had a lot of problems in my code because of the Unwrapping optionals. Why you didnt needed any of that?

But X and Y would be string, right?, you just can compare them and the compiler knows that it should treat them as integers?

I... just dont understand. Why are the curly braces after Array()?.

Because we didn't need to. If you start fromn 0, you are adding 0 + 1 + ..., what would be the point of adding 0?. So you start from 1. 1+2+...

setattr(object, name, value)
    This is the counterpart of getattr(). The arguments are an object, a string, and an arbitrary value.
    The string may name an existing attribute or a new attribute.
    The function assigns the value to the attribute, provided the object allows it.
    For example, setattr(x, 'foobar', 123) is equivalent to x.foobar = 123.

wut

wut