what ' , x ' means in lambda?

this kata makes me feel bad :(

this is awesome

Nice one !

This one actualy seems pretty good! But it also works without square brackets. So I really didn't get, what we use them for? Can someone please clarify this for me?

yes

I think, this is the best (short and quick understanable) solution, just if you know what the "floor division" is!

This code passes the tests.

This is literally the same code I came up with and kept failing due to not passing 50 char limit.

I had to forfeit eligibility just to to see this answer.

Went back in and it still fails.

Smh.

Yep, this is O(n²) for the reason you explained.
And I disagree with RazNaot, just because you can solve a problem inefficiently doesn't mean you should. The goal of this website is to improve at programming.

Good!

Using & operator with two sets creates a new set containing the elements present in both sets.

https://docs.python.org/3/library/stdtypes.html#set for more infos. :)

yes!

You got advantage of dictionary duplicate updation behaviour .. good one