Three technical phone interviews were conducted.

The interviewer asked a lot of questions about my resume and posed technical questions, such as basic OO design issues and basic coding questions.

The conversation with the interviewer was pleasant.

I was asked many questions, most of which were easy. However, they decided I failed the interview because I had trouble with one question. They did not specify which question led to my failure.

I suspect that although the questions were generally easy, you have to be 100% accurate in order to pass the interview.

How do you do an object-oriented design for a list of animals in a zoo?

Given an integer, return its corresponding ASCII character representation without using built-in language features.

Example: input integer 1234, return "1234" as a string or characters.

What is a Fibonacci function that returns the Nth position number? Provide both recursive and iterative implementations, and explain the time efficiency of both.

What is a HashMap? Compare HashMap and TreeMap regarding their efficiency for intersection and traversal.