Amazon Software Development Engineer interview questions

I had three phone interviews. No onsite. First one went really well, second one was so so, third one (decider) did not go well. Here were my questions spread over all three interviews (that I remember): 1) Return the nth fibonacci number 2) Asked me some basic OO questions (interface, abstraction, OO) 3) Write isBalanced(String str), which returns true or false for whether or not the string has properly matched and balanced parentheses 4) Design a parking lot system 5) Design a chess system. I wasn't feeling it with the interviewer in the second and third interview. When you get stuck, stay position. Keep talking about what you're thinking. Keep engage. Try to stay relaxed and a solution will come to you.

phone interview, 1 round. Some kinda previous project experience. OOP concept, polymorphism, SVL.