How is it brittle? It solves the problem at hand, which is unambiguous (I think).

Maybe those who care about computational complexity for instance?

Even if you had terabytes of data sorting is still the easiest answer. Especially if you had terabytes of data in fact. Brittle solutions suck

Start with what works and then optimize

Sophomoric is exactly the word here, and it’s no surprise that the story is about Microsoft

Am I missing something or sorting is n.log(n) when the sum trick is linear time?

In the lack of additional constraint, sorting seems massively overkill.

Not sure why you are saying that sorting is simpler than the sum trick.

The author spent days thinking about it, whereas sorting is the immediate obvious answer. Developer time is massively more valuable than computer time by a factor of 1000

And the clever approach only works on data that is perfect, and that’s extremely rare in the real world

This is a hypersophomoric question