> I can't think of any real-world situation in which the developer couldn't solve this problem better by ensuring it never needs solving at all. That's assumin

> I can't think of any real-world situation in which the developer couldn't solve this problem better by ensuring it never needs solving at all. That's assuming a lot already. The array might have come in externally, with no control over the cadence and format it arrives in, so no way to "keep track" until you are handed the final state.