> Unless you actually work in an environment where it's critical find the optimal solution to a large constraint search problem in 30 minutes or the tower blows up I don't see what the difference is to taking a couple of hours to find the solution.
Not to mention, if this scenario is frequent enough that you really need to screen for it in interviews there is probably something fundamentally wrong with the way you are running your business.
And yet it's bewilderingly common to use it as a low-pass filter.
The reason I like the suggestion is that it asks the candidate to show you how something works which seems like it would demonstrate their ability to understand a topic, how they approach it, and importantly whether they can communicate what they know in a way that other people can understand.
I'm more interested in whether a candidate can write a decent bug report and form a coherent patch than how many puzzle solutions they've memorized to slip through my filters.
Not to mention, if this scenario is frequent enough that you really need to screen for it in interviews there is probably something fundamentally wrong with the way you are running your business.