Yahoo Front End Web Developer interview questions

I got referred by my instructor, who worked with Flickr for 3 years, so I got interviewed 3 times in a period of 3 months. The first two were within the first three weeks, and the last one was later. The first interview was a coding challenge, which I aced, the second one was with the head manager, talking about random things, and lastly was another coding challenge, which was difficult because I didn't experience something like it before. I didn't receive a response yet, as I just finished from my third interview, however, I believe I didn't do well it up.