Cod sursa(job #1944888)

Utilizator tudortarniceruTudor Tarniceru tudortarniceru Data 29 martie 2017 11:57:41
Problema Invers modular Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 0.52 kb
#include <fstream>
#include <cstring>
#include <algorithm>
#define ll long long
using namespace std;

ifstream fin("inversmodular.in");
ofstream fout("inversmodular.out");

ll a, n;

ll exp(ll x, ll y) {

    ll r = 1;
    for (ll i = 0; (1 << i) <= y; ++i) {
        if ((ll)(1 << i) & y) {
            r *= x;
            r %= n;
        }
        x *= x;
        x %= n;
    }

    return r;
}

int main() {

    fin >> a >> n;
    fout << exp(a, n - 2);

    fout.close();
    return 0;
}