Cod sursa(job #2178138)

Utilizator IulianOleniucIulian Oleniuc IulianOleniuc Data 19 martie 2018 10:26:36
Problema Suma divizorilor Scor 70
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.04 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() {
    sol = 1;
    fin >> a >> b;

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

        if (d % MOD == 0)
            continue;

        if (exp) {
            int fact = (pow(d, exp * b + 1) - 1) * modInv(d - 1) % MOD;
            if (fact < 0)
                fact += MOD;

            sol = sol * fact % MOD;
        }
    }

    if (a > 1 && a % MOD) {
        int fact = (pow(a, b + 1) - 1) * modInv(a - 1) % MOD;
        if (fact < 0)
            fact += MOD;
        sol = sol * fact % MOD;
    }

    fout << sol << '\n';
    fout.close();
    return 0;
}