In a previous post, I proposed a replacement for the FizzBuzz problem as part of the BrainSharpener series. As most people recall, the aim of the FizzBuzz problem was not to provide people with an extreme challenge. As the blogger noted, it was merely to identify programming competency. And similarly, the aim of this FizzBuzz Replacement, the base 15 converter problem, was not to stump the programmer. Instead, as opposed to Imran's goal, the intent here was to highlight a common behavior that is lacking sometimes.
Q. What is this behavior you ask?
A. Listening, or rather paying careful attention to what the interviewer is asking for.
Ironically, the first person to come up with a response fell victim to this: http://geekswithblogs.net/yowhann/archive/2007/03/21/109468.aspx#109526. In any case, the intent here is NOT to embarass anyone. But it is rather to point out a very real possibility that was not highlighted in the FizzBuzz blog entry. And that is: differentiating between individuals who consistently miss requirements vs. people who just happen to miss it in the heat of the moment or are under interview pressure. I am the first to admit that I fall victim to this ocassionally. But the key here is whether the individual does it consistently.
As an interviewer, the only way you can identify this is with several whiteboarding problems and observing not just their solution, but how they break down the problem. In this case, being a very trivial question, you may not expect them to write down notes first. But for more complex problems, telltale signs that they are methodical and pay attention to the question include:
- Verbally communicating the requirements and/or confirming details with you
- Circling or underlining key points (if you wrote down your problem on paper or whiteboard)
- Writing a couple bullet points before coding out the solution
- Depending on the complexity of the problem, diagramming a state or workflow diagram
Of course, there are cases where people are just not very vocal and also don't express themselves very well on paper/whiteboard. But I think you get the idea...