Yelp Software Engineering Intern interview questions

Signed up at a campus career fair, they emailed a bit after saying they wanted a phone interview. That was quick and I found almost all questions on Glassdoor. The next step was a 45-minute Skype interview, which was just as quick but went into in-depth data structures and other things I had yet to review. I was caught a little off guard by some of the things I was asked to explain, so I had to respond that I didn't know, which they were okay with. There were two or three main problems and it would've gone quickly if I had known them, but I was instead stuck and had multiple dead silence moments.