Hey it could be worst, i know how to use it and still used it wrong .-.

how do you actually know all of this stuff

Wow

Just as I clicked submit, I envivisioned (as I usually do) what the one line solution would look like and just as I thought of abs(), here it is. Dammit.

Poor guy, lol

I submitted the solution above and one slightly refactored variation 9 years ago. I definitely did not copy from StackOverflow and I claim my solution original. I have no idea how a number of people came up with the exact solution of mine. Note that you can see other solutions once you solved a kata. Interestingly many of the accounts above where suspended.

I mean runtime because of an additional function call.

solutions were copy pasted from the internet (stackoverflow) probably.

What do you mean by expensive? As in it takes a lot of system resources compared to over operations?

-0 == 0 == +0, try it in the interpreter

Nice!

Just stop.