This is more efficient than the top solution becuase the character counts are only computed once.

Most efficient solution I've seen, very nice.

It shouldn't be, how do I disallow a module?

Also, I'm adding negative numbers to the test cases, thanks.

Hmm well played. I should have disallowed the matrix module.

Is this inefficient because its sorting the array n times instead of 1? Or does it get optimized to just 1 time?

I can see the two translations but I'm not sure how to approve them.

Edit: I think I figured it out.

I can do more linear algebra katas if there's interest.

Done.

Ah, I made a mistake when I typed out the test cases. The function should only take one argument which is a nested list of rows. Sorry about that.

I made the corrections, want to give it another try?

Are you sure? I just tested the submit tests and they seemed to be working fine.

Edit: I fixed a typo in the description and testcases where I wasn't nesting rows into a list. Is it working for you now?