Re:Fast Perfect Hashing
by ychen306 on Wednesday February 13, 2019 @04:12PM
(#19157053)
I really dislike posts like this one. For technical stuff like this people should start out with definition so everyone know what the author means by, for example, "perfect hashing".
> By implication, the hash must be at least as many bytes as the key and the function is theoretically reversible
No. At least not by the standard definition[1]. In standard context, the problem of constructing a perfect hash function is, given (ahead of time) a list of items, you find a hash function that can map them to a smaller "range" without collision.
> By implication, the hash must be at least as many bytes as the key and the function is theoretically reversible
No. At least not by the standard definition[1]. In standard context, the problem of constructing a perfect hash function is, given (ahead of time) a list of items, you find a hash function that can map them to a smaller "range" without collision.
[1] https://en.wikipedia.org/wiki/Perfect_hash_function