hash-func.cpp

#include <iostream>
#include <string>

using namespace std;

long long compute_hash(string const& s){
    const int p = 31;
    const int m = 1e9+9;
    long long hash_value=0;
    long long p_pow = 1;
    for(char c: s){
        hash_value = (hash_value+(c-'a'+1)*p_pow)%m;
        p_pow = (p_pow*p)%m;
    }
    return hash_value;
}
int main()
{
    string text = "Hello World";
    cout << compute_hash(text);

}