EF Education First interview questions

I was brought in first for a group interview, then for three one on one interviews. The group interview was with about 8 other prospective employees. It started with a general introduction to the company, then we all introduced ourselves and several of the managers also introduced themselves. Then we all went around and had mini interviews with each of the managers, with each interview lasting about 4 min long. Overall a little intimidating at first, but ultimately pretty fun. My one on one interviews were with three of the managers, two who I had previously met/spoken with, one who I had not. They asked very individualized questions, trying to see what type of person you were, etc. Each interview lasted 45 min to 1 hour.

Got call from hiring agency, they called for F2F interview at EF office. Though i had gone for iOS position they kept on asking me to solve algorithms in C which is highly unprofessional to judge a person on what he doesn't know. Interviewer gave few algorithms to solve and then asked about Core data and other iOS work. They said they will get back and did not turn up. No courtesy to say what went wrong.