Question d’entretien chez AOL

Relatively simple and easy questions. Phone interview: 1. Given a positive integer n, implement a function that returns the nth number in the fibonacci sequence Onsite interview: 1. First the interviewer asked me how to implement a function that checks if a sudoku table is valid or not, but since I worked on this question the night before, he gave me a different one. Given an array of integers, where each integer represents the color of the ball, how can you sort the array so that, red balls are first, then blue ball, then green balls. 2. Cant remember the exact question but it was a recursive solution. Basically you are given a JSON object and you basically want to recurse through each property and print value depending on the value of the property. 3. I cant remember this exactly but it was copying some array in C.