Jump overflow and underflow semantics should definitely be specified in the problem, omitting them and then let people try to guess does not make a good problem, but a bad spec.

(For those stuck: Overflow should make your program terminate, not throw exception. Underflow is not relevant (I think), but I made it just stop at the first instruction.)

Thank you very much!

One-liners tend to have that side-effect... And it probably is the case here.

However, remember that «Premature optimization is the root of all evil»: If I would have to create a big bunch of variables to avoid recalculations, the code would become unreadable quite quick.

Furthermore, nothing is won when you replace two calculations with an assignment and a calculation! You only start to win something with three or more recalculations avoided!

Sorry!

And I would never write this in production code!

A simple refactoring into a helper function would make this much more digestible!
Alas, the "one-liner factor" was too appealing... :)

I don't know if this has been updated, but I have been able to solve this problem. Perhaps you are summing number by number? There are more efficient ways!

"tl;dr"

Best comment ever!