Today is not my lucky day. It was a panel interview. There were three people interviewing me, two developer, one manager. Question 1: There are 100 stairs, you can either go by one or two stairs each time, how many different ways(combinations) there are to climb the 100 stairs. For example if there are 3 stairs, there are 3 ways: (1,2), (2,1), (1,1,1). Question 2: Given the location n, print out the nth number in a Fibonacci sequence. Question 3: There are two tables, manager and employee, using sql query to return the managers whose id isn't presented in the employee id column of employees table. I couldn't give out a generic answer for the first question. And for the second one I used an actual array to save the elements. Right after the interview I realized these two questions are essentially the same, and can be solved very efficiently using recursion. I missed out their hints.