I've recently been reading some articles opposing the use of brainteasers during interviews on the grounds that they are unfair and some people have difficulty thinking on the spot. You can make the same argument for any part of the interview process and I feel that brainteasers may even attract intelligent employees.

I can come up with a few good reasons to use brainteasers during an interview. One, you are able to determine how well the interviewee thinks as well as their problem solving ability. In addition, if the interviewee does end up getting a job offer, he or she may be more likely to accept it since it was a challenging interview and getting the job feels like an accomplishment - feels better when you have to earn something than when it falls into your lap. The fact that you even asked a brain teaser shows intelligence on your part and you want to attract people who want to work with other smart people, instead of being the big fish in a small pond.

Ideally, you would want to find some brainteasers that have multiple ways of solution so you are able to identify how each of the interviewees thinks but I think a variety of brain teasers can achieve the same effect. Below are few good questions/brainteasers I enjoy.

1. What was the last book you've read? What's your favorite book? (Not a brainteaser but I believe a good question nonetheless)
2. You have a lighter and 2 ropes that are non-uniform. It takes a rope 1 hour to burn from one end to the other end. How do you measure 45 minutes?
3. You have 3 pairs of (x,y) points that determine a triangle. How can you determine if this triangle contains the origin? (from Project Euler)
4. Which is larger, 48736^95934 or 44390^96771? (Also from Project Euler)
5. How do you split a cake of nonuniform size between 2 people? Can you expand this to any number of people?

Feel free to comment or email me if you are unsure how to solve a particular problem.