[anonymoushn]

I think it's not such a big deal because the input generators are usually pretty good and because most solutions that give up some correctness for performance can pretty cheaply detect that they done goofed and fall back to a slow path where they start over and do it some other way. This ends up being useful because scoring is the median runtime of 3 successful runs (so if you fail one of the 3 then your submission fails completely). It also means that probabilistic solutions that would be correct in non-adversarial environments (like using a bloom filter or N bloom filters tuned to give an exact result given the input constraints with probability >99.9%) are admissible.