I mean, there's a problem in that borderline people generally know what to study for with these kinds of interview questions nowadays, hurting accuracy, but HackerRank is still great because it lets companies filter out dumb people and recognize smart people more efficiently. It also means that the few intelligent students at second-rate universities like SJSU, Drexel, Howard, etc, have better access to the job market instead of just being ignored by everybody who wants anybody good.