Where's all this newfound interest in hash maps coming from? Once you hash something, you lose the prefix information, making it kinda' useless for this activity. Unless you create a hash for every string length variation... but, that seems like a lot of overhead for very little gain.
I also can't see how you'd get that negative match fast path performance if you were reliant on hashes. That owes its speed to the length and unique char filter working in concert.
I also can't see how you'd get that negative match fast path performance if you were reliant on hashes. That owes its speed to the length and unique char filter working in concert.