No, they are not. I was looking to create a square shape, but it wants a square number instead. EDIT: description updated

omfg i did't even thought about it, its so obvious...

Please, mark your post as having spoiler content next time.

I assumed that we are not allowed to modify the matrices received by parameter (it is very common to pass large types like a matrix by reference to const) but you could use one of them to store the result and return that instead of allocating a new one.

Do I really need to allocate memory for output and row vectors?

filter won't sort the resulting array.

filter tends to sort the resulting array which according to the instruction is not allowed.

They really are, though

The description and the examples aren't good enough.

Try again, please

Description cannot be approved, recent changes from related record must be merged first.

Can't approve it. Please republish it.

actually not...

crappy description of problem...