Booking.com IOS Developer interview questions

The process took 2 weeks. I applied online through StackOverflow. Initially an HR person emailed me that my profile got selected for the interview process. First she confirmed a phone interview. So the first round was with HR, who asked few questions like 1. My motivation, 2. Idea about how Booking.com operates, 3. how it monetise through its website and app, 4. what you feel that it can be improved in the app etc.. Basically an assessment of my overall understanding of Booking.com through its app and booking websites. Then a normal employment history checking, Among the applications you developed so far, what application you feel is most complex and why? So finally after this 30 minutes, she confirmed me for the next round of technical interview. She emailed me about the details, and given some tips about attending the technical round, like going through Hackerrank, Euler websites for coding practices under time pressure. And the email had a website link and password for proceeding to write a live coding assignment with the interviewers. After 2 days, I was called for second round through phone by two iOS developers. They asked me about, how you feel about the Booking.com iOS app. Then asked me to proceed to the live coding notepad(TitanPad). There they pasted the questions from Objective-C