Nice one! I've really gotta get better at that format string syntax!

Very cool!

You can't write a solution that runs faster than this tbh

Why doesn't this time out?

genius

This is good.

iteritems and itervalues don't even exist anymore in Python 3 (this is an old solution). But yes, values would be more efficient than items.

I didn't know this either. My code golf just leveled up.

I mainly meant efficient in the code golf sense of not requiring many characters. :) Yes, the floor division method is more performant.

Omg. Of course. I'm an idiot. XD

Thanks for the feedback! I updated the description to clarify that respondents should use "rounding to even", which is (to my understanding) the default behavior of both round and format in Python. I suppose I should add explicit tests for this too.

A little inefficient because it checks pairs twice, but simple and intuitive!