Brain teaser questions are great at finding candidates who have heard the brainteaser before. They are useless at finding people who are good at coding. Even Google accepts this now.
I would ask why if I had 8 L of water containers why I would try to figure out how to have no more than half of that and just fill both jugs, then I'd say that's a stupid question and has nothing to do if I can code or not. I hate these stupid job interview things just be frank and lets talk about my skills and what you're looking for, not stupid brain teasers, fizzbuzz, or anything like that.
