C++, what is a good way to hash array data?

Question

hello

I have a curious problem and I am brainstorming possible solutions. The problem is such: I have a number of inputs (up to several thousand different ones), which basically differ in two-three arrays (arrays are a different size generaly, from size one up to couple thousand elements long). the functions which process arrays take some time to initialize data, so i thought to cache function/functor together with data and store them in map.

now, how do i go about converting raw arrays into usable hashtable type? i initially thought to read array into a string and use string as the key. is it good idea? do you have better suggestion?

thanks

Answer 1

Are these arrays integer? If yes, just go with something like this

hash= (hash+(324723947+a[i]))^93485734985;

Similar thing would work fine for strings if you do it on all characters.

Finally, you may check out extra libs: http://www.boost.org/doc/libs/1_42_0/doc/html/hash.html