Cod sursa(job #2452590)

Utilizator verde.cristian2005Verde Flaviu-Cristian verde.cristian2005 Data 31 august 2019 13:24:41
Problema Invers modular Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.64 kb
#include <fstream>
using namespace std;
ifstream in("inversmodular.in");
ofstream out("inversmodular.out");
long long A,N;
int fi(int n)
{
    int rez=n,d=2;
    while(d*d<=n)
    {
        if(n%d==0)
        {
            while(n%d==0)
                n/=d;
            rez=rez/d*(d-1);
        }
        d++;
    }
    if(n!=1)
        rez=rez/n*(n-1);
    return rez;
}
int lgput(int a,int b)
{
    long long rez=1;
    while(b)
    {
        if(b%2)
            rez=(1LL*rez*a)%N;
        a=(1LL*a*a)%N;
        b/=2;
    }
    return rez;
}
int main()
{
    in>>A>>N;
    out<<lgput(A,fi(N)-1);
    return 0;
}