[shkkmo]

> So let's say someone doesn't have any experience traversing trees (why would they? you rarely have to, if ever).

Ummm... what? Basic DFS of trees with nested foreach loops is incredibly common. It is not a generic, depth blind traversal, but it most certainly is tree traversal.

> You're presenting them with a new problem and expecting them to come up with the most efficient/concise solution to that problem. The only people who get rewarded here are people that simply memorized the solution or the solution space. In effect you've validated nothing.

If somebody gives up on solving such a simple problem, why would I ever want to hire them?

> The only people who get rewarded here are people that simply memorized the solution or the solution space

Says who? You are making a bunch of assumptions about why the question is being asked.