What's the Best Interview Format in Tech Companies?

The interviews are about two hours in length. We spend about 30 minutes on each section. And all of that's done remotely because the person's at home, right? Oh, yes, we do this all over Google hands. Okay, and so what’s a reasonable amount of time for someone to just like go through one of these exercises? Are they all widely different or? The people who answer well must be smart and good programmers; the people who get tripped up must not be.