Cod sursa(job #719174)

Utilizator deneoAdrian Craciun deneo Data 21 martie 2012 15:33:00
Problema Invers modular Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.45 kb
#include <fstream>
using namespace std;

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


int inv(int a, int mod) {
    int i, rez = 1;
    for (i = 0; (1 << i) <= (mod - 2); ++i) {
        if ((1 << i) & (mod - 2))
            rez = (rez * a) % mod;
        a = (a * a) % mod;
    }
    return rez;
}

int main() {
    int a, b;
    fin >> a >> b;
    fout << inv(a, b) << "\n";
    fout.close();
    return 0;
}