I got this right, but ended up having to invent notation to keep track of the indirection in the last segment. I think it's likely a decent test of whether you're likely to quickly pick up an intuitive head for pointer math and a very basic variable name-value distinction, but it won't capture other forms of abstraction that're necessary for programming: loops, types, conditional branching, Boolean logic. You could probably get away with dropping conditionals (I get the impression they're fairly intuitive), but I've had trouble teaching the others in the past.

Has a bit of an old-school feel to it, too; I'd expect the results to correlate better with talent for C than they would with, say, Python.