They didn't take into account that floats come with an estimated uncertainty, and that values that are the same within the limits of experimental error are identical? That's a really badly set problem!
I think it that particular case they just didn't do error analysis.
The task was to output answer with `10^-6` precision, which they solution didn't achieve. Funnily enough the number of other teams went the "correct" route and passed (as they were doing additions in same order as original solution).
The task was to output answer with `10^-6` precision, which they solution didn't achieve. Funnily enough the number of other teams went the "correct" route and passed (as they were doing additions in same order as original solution).