cool

Yes. bitwise-or of the modulo(remainder). It is only zero if both modulos are zero.
When using it on bools you have to be a bit careful, as (1 | 2) is 0011, and that is stored in boolean. true is 0001, so while (1 | 2) evalutes to true, it's not equal to true in some way. Here it's fine, but be aware. Negating with ! (boolean not) "normalizes" it to 0000 or 0001 though. ~ would be the bitwise not.

bitwise-or may be faster as it does not branch (both sides are always evaluated), as opposed to boolean or. But don't rely on that.

is this the bitwise OR operator?

nice man good job ?? !!

it's really clever but indentation is not very good.

nice coding

nice

Oh, that's right! Thank you

I like this Kata! One small issue is that the function in the starting code is minmax_areas(). But the function tested is maxmin_areas()

One way is to come up with an algorithm which takes linear time and goes through the list once only.