I think implementing min is slightly different to remembering the rotation algorithm for an AVL tree (for example). But still, my point wasn't to not test, it

I think implementing min is slightly different to remembering the rotation algorithm for an AVL tree (for example). But still, my point wasn't to not test, it was to allow the candidate all of the tools of their trade whilst being tested. 'Air coding' (a phrase I use for white-board/paper/verbal coding) is not a good indicator in my humble opinion.