Cod sursa(job #3280701)

Utilizator liadariaLia Daria Ostafi liadaria Data 27 februarie 2025 11:27:35
Problema Invers modular Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.76 kb
#include <fstream>
using namespace std;
ifstream fin("inversmodular.in");
ofstream fout("inversmodular.out");
int Phi(int n);
long long int exponentiere(int x,int n);
int a,mod;
int main()
{
    fin>>a>>mod;
    fout<<exponentiere(a,Phi(mod)-1)<<'\n';
    return 0;
}
int Phi(int n)
{
    int d,f;
    f=1;
    for(d=2;d*d<=n;d++)
    {
        if(n%d==0)
        {
            while(n%d==0)
            {
                f*=d;
                n/=d;
            }
            f/=d; f*=(d-1);
        }
    }
    if (n>1) f*=(n-1);
    return f;
}
long long int exponentiere(int x,int n)
{
    long long int a;
    if(n==0) return 1;
    if(n%2==1) return x*exponentiere(x,n-1)%mod;
    a=exponentiere(x,n/2);
    return (a*a)%mod;
}