Ixigo.com Software Engineer iOS interview questions

1st round was about basic iOS understanding and fundamentals . 2nd round was ds algo question i was given an array based question which you need to solve with an optimised solution not brut force approach . 3rd roud was advance iOS round where concepts like multithreading and architecture are asked . ceo round was best round I must say it was a duscussion , about your logical thinking and what is your approach toward an problem how you create an algo.