I'm fairly confident that if asked to hash out a solution to this on a whiteboard in an interview situation, the stress of being put on the spot would impede my ability to perform up to par, and I'd probably come across as inept.
There's a mistaken assumption here that because you're a competent programmer you're expected to solve these exercises with ease [1]. If you're interviewing with that expectation, you'll have a huge false negative rate and only hire people with nerves of stainless steel. Even experienced programmers can make very silly mistakes when coding under pressure in front of an audience.
What you're expecting to see is that the person can reason, knows the basic syntax of the language he claims to be familiar with, and doesn't make any mistakes that show a total misunderstanding or unfamiliarity of how it works. (Put differently, have they read a book/website of examples of the language, or have they actually coded in it?)
If you point the experienced programmer that's very nervous a few of his mistakes, you're expecting him to show sheer terror and panic as he realizes what he's done [2]. If the candidate is showing you a blank stare instead, you might have a problem.
If you're only verbally interviewing and asking for code samples, you can get fooled easily. Some candidates think that if they can bullshit their way through the interview, they'll stay hired. And sometimes, they're even right, because most people don't like to fire.
At some point, we were having serious problems filling positions and started de-emphasizing doing bad/mediocre on the coding part of the interview, and focus more on the experience and verbal interview, on the assumption radiated in many posts here that serious coders might not necessarily be able to show their ability in a coding interview. All of those hires turned out to bad.
You'll have a hard time convincing me now that coding interviews aren't effective.
[1] The example here is FizzBuzz. Why is it so trivial that many people can't believe it works? Because even good coders will fuck up more complicated questions in interviews.
[2] Just as an observation and nothing more: experienced coders tend to also not being able to bear the sight of those mistakes and insist on being allowed to correct them even if told it really doesn't matter.
There's a mistaken assumption here that because you're a competent programmer you're expected to solve these exercises with ease [1]. If you're interviewing with that expectation, you'll have a huge false negative rate and only hire people with nerves of stainless steel. Even experienced programmers can make very silly mistakes when coding under pressure in front of an audience.
What you're expecting to see is that the person can reason, knows the basic syntax of the language he claims to be familiar with, and doesn't make any mistakes that show a total misunderstanding or unfamiliarity of how it works. (Put differently, have they read a book/website of examples of the language, or have they actually coded in it?)
If you point the experienced programmer that's very nervous a few of his mistakes, you're expecting him to show sheer terror and panic as he realizes what he's done [2]. If the candidate is showing you a blank stare instead, you might have a problem.
If you're only verbally interviewing and asking for code samples, you can get fooled easily. Some candidates think that if they can bullshit their way through the interview, they'll stay hired. And sometimes, they're even right, because most people don't like to fire.
At some point, we were having serious problems filling positions and started de-emphasizing doing bad/mediocre on the coding part of the interview, and focus more on the experience and verbal interview, on the assumption radiated in many posts here that serious coders might not necessarily be able to show their ability in a coding interview. All of those hires turned out to bad.
You'll have a hard time convincing me now that coding interviews aren't effective.
[1] The example here is FizzBuzz. Why is it so trivial that many people can't believe it works? Because even good coders will fuck up more complicated questions in interviews.
[2] Just as an observation and nothing more: experienced coders tend to also not being able to bear the sight of those mistakes and insist on being allowed to correct them even if told it really doesn't matter.