[pjlegato]

Knowing what these structures are and having a working knowledge of how to use them is not the same skill as being able to implement them from scratch (on a whiteboard, in an hour or less.)

If you can drive, you probably have a pretty good idea of whether a car or a truck or a motorcycle or a tank is the best vehicle for a particular transport application, and you can probably actually drive all of those with minimal practice. That doesn't require you to know how to build a car, a truck, a motorcycle, and a tank from scratch. That's a different skillset.

Google pays far above market rate, so they have the luxury of hiring petrochemists to work a gas pump. Even at Google, once all the shiny is stripped away, most of the projects are simple CRUD.

[bmay]

1) If you know what a DAG is and how to use it, you can most likely implement and traverse one in way less than an hour.

2) I've never heard of anyone being asked to implement a red-black tree during a Google interview.

[vonmoltke]

> 1) If you know what a DAG is and how to use it, you can most likely implement and traverse one in way less than an hour.

I know what it is and how to use it. I can implement and traverse one. I seriously doubt I could do it in an hour, especially if I don't have at least standard library documentation available.

[Ar-Curunir]

Whiteboard code interviews don't require you to flesh out such things in any great detail; they're intended as proxies for your thinking process.

[vonmoltke]

You should tell that to some of my whiteboard coding interviewers, then. Plus, I feel that many of the interviewers who claim to be interested in though process still have a "right" way in mind and will dock interviewees for not approaching a problem the way they would.

Anyway, the post I was replying to said, " you can most likely implement and traverse one in way less than an hour" (emphasis mine). That statement has nothing to do with thought processes. To me, that requires "flesh[ing] out such things in any great detail".