Ah, I see now. I haven't realized instructions other than left/right cost anything. My solution should work in "real time".
(and even that could be done in two as well as I see now)
I already closed it, so might be a bit different, but essentially this: https://paste.fedoraproject.org/285179/62077561/ https://paste.fedoraproject.org/285179/62077561/
I guess my interview wouldn't go that well :)