Cod sursa(job #1510725)

Utilizator Bogdan1999Draghici Bogdan Bogdan1999 Data 25 octombrie 2015 15:54:41
Problema Invers modular Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.71 kb
#include <iostream>
#include <fstream>
#include <cmath>

using namespace std;

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

int fi(int n)
{
    int f=n, i;
    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 put(long long a, long long b, int c){
    int p=1;
    while(b!=0){
        if(b%2==1){
            p=(p*a)%c;
            --b;
        }
        a=(a*a)%c;
        b/=2;
    }
    return p;
}
int main()
{
    long long int a, n, x;
    fin>>a>>n;
    x=fi(n)-1;
    fout<<put(a,x,n);
    return 0;
}