They should just check and compare efficiency on the back end and rank solutions by most efficient then by best practice.

Shame :(

Adding a downvote button on solutio could help in this aspect.

I just asked for one on the feature request page, go there and vote up my comment if you want to see this. It really is needed to stop these really ineficient algos from making their way to the #1 spot just because they take up fewer lines.

Is there any request for a efficent voting mechanism? I would love that.

True, this solution is VERY inefficient

Yay! I'm really happy to see someone use Euclid's Algorithm! It looks a lot simpler in code than wikipedia makes it look.

Terse low-performance solutions seems to consistently get rated over more verbose solutions with better Big-O.

This problem should explicitly call out that:
-An input of 0 should return None, not 0
-Inputs may be strings. When they are, the function must return None

Sheeps isn't a word, but sheep is. It's the authors protest of the misspelling.

I'm not sure it's safe to assume that there are only a maximum of 3 WUBs in a row. If there were multiple, you'd wind up with several spaces in a row.