Cod sursa(job #2366203)

Utilizator Mihai145Oprea Mihai Adrian Mihai145 Data 4 martie 2019 18:56:58
Problema Invers modular Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.82 kb
#include <fstream>

using namespace std;

int GetPhi(int X)
{
    int phi = X;

    for(int i = 2; i * i <= X; i++)
        if(X % i == 0)
        {
            phi = (phi / i) * (i - 1);

            while(X % i == 0)
                X /= i;
        }

    if(X != 1)
        phi = (phi / X) * (X - 1);

    return phi;
}

int RidPut(int base, int exp, int mod)
{
    int ans = 1;
    int aux = base % mod;

    for(long long i = 1; i <= exp; i <<= 1)
    {
        if(i & exp)
            ans = 1LL * ans * aux % mod;

        aux = 1LL * aux * aux % mod;
    }

    return ans;
}

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

    int A, N;
    fin >> A >> N;

    int phi = GetPhi(N);
    fout << RidPut(A, phi - 1, N);

    return 0;
}