I think that is perhaps telling. Google doesn't interview you on your experience, but whether you can can solve network/graph algorithms taken from Knuth exercises. I would expect a random mess from that. It sounds like this person actually drilled down into what the candidate actually knew.
I think it is far more useful to ask somebody about what they actually did. Are they excited and engaged by it, did they come up with novel thoughts about it, do they understand the CS literature in relation to it, and so on. Program a hash table on the whiteboard when you have been just fine using the built in one in your favorite library or language? I'm not sure what that predicts about my on job performance. If I had to do that I'd reread the literature and then whip one up, easy peasy. I can state that with confidence because I read the literature on other topics and do that every day. Have me explain the new numerical filtering technique I just implemented and I'll give you good interview. Ask me to implement a smart pointer? Not so much.
This doesn't make sense to me on first read. I'm unaware of a labor law that requires you to interview people without college degrees. Care to elaborate?
I may have worded it wrong. A large swath of programming jobs do not require a college degree, and in those cases it's illegal to require one. This is why job ads will say, "Desired: College degree or equivalent experience." They don't describe it as a requirement for a reason.
If you design your interviews to focus on knowledge and abilities taught in college, you tend to cut out people without college degrees who don't have the personal grit to go teach themselves those subjects. Since most people don't care for academic learning, this effectively requires a college degree in general.
That said, the big G does hire a number of people without degrees, I hear.
I think it is far more useful to ask somebody about what they actually did. Are they excited and engaged by it, did they come up with novel thoughts about it, do they understand the CS literature in relation to it, and so on. Program a hash table on the whiteboard when you have been just fine using the built in one in your favorite library or language? I'm not sure what that predicts about my on job performance. If I had to do that I'd reread the literature and then whip one up, easy peasy. I can state that with confidence because I read the literature on other topics and do that every day. Have me explain the new numerical filtering technique I just implemented and I'll give you good interview. Ask me to implement a smart pointer? Not so much.