As other commenters alluded, interviewing and coding are indeed two different skills. However, contrary to some of the comments, I don't think there is anything wrong with preparing for an interview or even taking an entire course for that matter. If it helps you shine and showcase your real skills to an employer then why not? I’ve seen many brilliant software engineers get rejected for positions cut out for them only because they were so nervous at interviews that they had trouble even understanding simple questions until right after the interview ended. I know that because I'm a co-founder at Pramp.com, a free p2p mock interviewing platform for software engineers. It's incredible to see the improvement in one's confidence even after a single practice interview.