Cod sursa(job #2177535)

Utilizator IulianOleniucIulian Oleniuc IulianOleniuc Data 18 martie 2018 17:33:56
Problema Suma divizorilor Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.82 kb
#include <fstream>
#define MOD 9901

std::ifstream fin("sumdiv.in");
std::ofstream fout("sumdiv.out");

int sol;
int a, b;

int pow(int a, int b) {
    if (!b)
        return 1;

    if (b & 1)
        return a * pow(a * a % MOD, b >> 1) % MOD;
    return pow(a * a % MOD, b >> 1) % MOD;
}

int modInv(int x) {
    return pow(x, MOD - 2);
}

int main() {
    fin >> a >> b;
    a = pow(a, b);

    for (int d = 2; a > 1; d++) {
        int exp = 0;
        while (a % d == 0) {
            exp++;
            a /= d;
        }

        if (exp) {
            int term = (pow(d, exp + 1) - 1) * modInv(d - 1) % MOD;
            sol = (sol + term) % MOD;
        }
    }

    if (sol < 0)
        fout << sol + MOD << '\n';
    else
        fout << sol << '\n';

    fout.close();
    return 0;
}