Applicants face two kinds of questions in tests with IT's giants. There are mathematical and programming/networking problems, with right or wrong answers, and questions designed to display how candidates' minds work. For the latter, there's no definitive answer, but there are bad ones, where candidates fail to display flair.
According to one Google interviewer, the company is looking for three pointers on suitability. How did the applicant go about reasoning their answer? How well was the applicant's response communicated, with analogies and passion? How relevant was it to the position?
The following are genuine interview questions, and we've collated the answers by drawing on interviews with recruiters, candidates and researchers behind the book Ace the Interview, published by Jeeve Technologies.
Q. You've got someone working for you for seven days and a gold bar to pay them. The gold bar is segmented into seven connected pieces. You must give them a piece of gold at the end of every day, but are only allowed to make two breaks in the bar. How do you pay your worker?
A. This question highlights how differently people think. Mathematically, the answer is relatively simple: the employer should cut the gold bar into three pieces, of one, two and four blocks respectively. On day one, he gives the worker the one-block bar, and on day two he takes the first bar back and gives the worker the two-block bar.
Day three, he gives the one-block bar back again, and on day four he takes both bars and gives the worker the four-block bar - and so on. This answer might be acceptable from a pure programmer, but it also has real-world problems that candidates should highlight.
For example, a project manager might point out that wages are for spending, and the worker might have cashed in his first bar on day one. Free-thinkers may suggest more creative examples, such as "take it to the bank and ask them to change it", or "melt it down".
Q. Why is a manhole cover round?
A. Again, there's no "right" answer, but the options show different thought processes. The practical answer, displayed by natural problem solvers, might be that round (as opposed to square) manhole covers can't fall into the hole no matter which angle they're dropped from, and also because it's the easiest shape for staff to move, as it can be rolled.
More compliant, orderly or cynical minds might suggest that the first manhole cover was round and that people are more likely to follow standards than question them. However, candidates with practical, finance and engineering strengths might suggest, equally correctly, that it's easier to bore round holes.
Q How can computer software be integrated in an elevator system for a 100-storey office building? How do you optimise for availability? How would variations of traffic over a typical work week or floors, or time of day, affect this?
A. The point of this and similar questions is to assess how well a candidate can picture and process the wider implications of a simple problem. In this case, it's a system architecture issue.
Candidates should address the most efficient pattern to service all floors, including a system that prioritises executive floors and limits idle time during peak hours. Candidates should also consider how multiple lifts can be co-ordinated to reduce waiting time, perhaps by programming lifts to service only certain ranges of floors.
Interviewees need to show that they can think not only about the elevator, but how people will use it. For example, based on weight, the candidate might suggest the elevator shouldn't stop on any floor unless there is space for two people - time-wise, it isn't worth holding up the whole lift to collect one passenger.