I got a call from 3rd party recruiter, and they scheduled my interview for the weekend, When I reached there I saw there were around 10-15 candidates for the interviews. I had to wait a lot because it was interview panel of just 2 persons (might be 3). So first round was for data structure and algorithms. The guy who interviewed didn't the difference between time complexity and space complexity (I am not kidding), So for a problem I proposed 2 solutions and I told him it depends on the requirement weather you want to use extra space or not. He was confused and was asking the "best" solution. One of the other question was implement queue using stack. First he told me to implement pop and push methods, then I asked him if he meant Enqueue and dequeue. So solution for this problem is done using 2 stacks but interviewer told me that I can only use one, later I realized he didn't realized that even recursive function call is going to use function call stack. He asked me 4-5 problems and I'm 100% sure that I answered each correctly. later there was an iOS round, that was really easy too, most of the questions were from the medium link when you type iOS interview questions. I believe I answered everything correctly. And later I find out I was rejected. I know what you must be thinking may be I misbehaved in interview. I was very polite and patient.