Microsoft Interview Question

Phone Interview: Fibonacci series(Time complexity), test cases for the function Onsite interview: 4 rounds on interviews with various teams.(Each team asked one technical interview and then questions to explain previous projects, purpose of projects, why I decided to take the approach I did ) Round 1: String Manipulation(Code+test cases) Round 2: String Manipulation(Code+how to handle big volume of files) Round 3: Lunch Interview about System Design(queuing techniques for games) Round 4: Core Java concepts: what is oops, explain its properties, data structure you are confident in and 1 technical question based on that, create a queue using stacks