Python 3.10

With what language?

Often i get output like this:

[
    ((-0.2129623804894449, 0.7707734797399344), (-0.20733777736872916, 0.7648529673512878)),
    ((-0.20733777736872916, 0.7648529673512878), (-0.2129623804894449, 0.7707734797399344))
] should equal [
    (-0.2129623804894449, 0.7707734797399344), (-0.20733777736872916, 0.7648529673512878)
]

when actually the two pair of points that my code outputs have the same distance (0.008166310501669808 if you check).
Also, my solution looks like O(nlogn) but it still goes out of time.

I updated to C18 but your solution crashes with both and not on an empty string. BTW how do you explain that 218 guys passed the C11 kata?:-)

Returning "" (an empty string) crashes the program with C11, while it doesn't crash with C18.