Yelp Software Engineer Intern interview questions

I got through the first round of telephonic interview. It wasn't hard. Basic questions testing CS concepts, some of which were stated on glassdoor. They ask you your interests, make sure you are clear on what/why. What follows now is a 45min skype interview with a tech person from the team you state interest to work in.

They originally came to my campus and emailed me several weeks later. They setup an initial HR phone screen which consisted of a dozen mostly easy questions. The recruiter doing the phone screen couldn't really answer my questions when I asked for clarification on the screening questions, because the recruiter wasn't that technical. I thought some were trick questions they were so easy, but you can find almost every question from this interview on glassdoor. Then I had another interview, which was technical and over skype with a young engineer. He asked me about my projects/resume, then got into some coding questions. I passed this interview and went on to another that followed the same format. If I could suggest one thing- practice recursion. I started solving all their problems iteratively and quickly realized that they were easily solved with recursion. After a solid second technical interview I got their generic rejection email. It was pretty sudden, I had gotten pretty far in the process (apparently a back-to-back interview was the only thing left). Several friends of mine were also in the same boat - a sudden rejection late in the process. So clearly they have a tough time making decisions. It seems like they waste a lot of time/resources on all these interviews when they only hire ~30 interns.