Three rounds about technics, and one round about basic situation. Interviewers are all friendly and technical. The technic interview didn't focus on too much about iOS development but your basic computer science knowledge.

The whole process took anout 1 week, 4 rounds in total, the first interview covers one coding question, max sum of sub array, some gerneral iOS questions like how you fell about Swift and some of your past experiences, the second round has a design question : how to implement a NSOperationQueue, the last two rounds mainly focus on Behaviourial Questions, like how you handle stress, how tto handle dispute with your teammates etc.