Cod sursa(job #1510713)

Utilizator raduaxel1Dilirici Radu raduaxel1 Data 25 octombrie 2015 15:40:39
Problema Invers modular Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.72 kb
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
ifstream fin("inversmodular.in");
ofstream fout("inversmodular.out");
long long fi(long long n)
{
    long long f=n, i, ok=1;
    for (i=2; i*i<=n; i++){
        if (n%i==0){
            ok=0;
            break;
        }
    }
    if (ok==0)
        f=n-1;
    else{
    for (i=2; i*i<=n; i++){
        if (n%i==0){
            while (n%i==0)
                n/=i;
            f=(f/i)*(i-1);
        }
    }
    if (n!=1)
        f=f/n*(n-1);
    }
    return f;
}
int main()
{
    long long i, a, n, x, nr=1;
    fin>>a>>n;
    x=fi(n);
    for (i=1; i<x; i++){
        nr*=a;
    }
    fout<<nr%n;
    return 0;
}