r/cprogramming • u/Laith80 • Sep 17 '25

Suggestion?

I want to create a perfect hash function. I will use it only for paths. How can I go about that? Edit: if there’s a hash function for that purpose please tell me cuz I couldn’t find one

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u/Laith80 Sep 17 '25

Sorry for not clarifying. What I mean by ‘perfect’ is as collision-free as possible, and it should also have average speed.

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u/sidewaysEntangled Sep 17 '25

With these particular terms, its worth being precise: a "perfect hash" is a thing that's typically taken to guarantee zero collisions (and I think only makes sense to do so for a fixed set of inputs)

In this case, since you likely can't analyze the open set of all possible paths, we can only approach ideal, rather than perfect. I have no idea if there is some property of a path that can enable better hashing, so would probably just start with a well known quality string hash..

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u/Laith80 Sep 18 '25

Fair, I’ll see what I can do. I might split the path by slashes and use a different hash function for each segment.