Cod sursa(job #2467806)

Utilizator NopeCarp Rafael Nope Data 5 octombrie 2019 08:39:48
Problema Invers modular Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.75 kb
#include <bits/stdc++.h>
#define MOD 1999999973
using namespace std;

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

int Phi(int n)
{
    int sol = n , i;
    for (i = 2 ; i * i <= n && n > 1 ; i++)
    {
        if (n % i == 0)
            sol = sol / i * (i - 1);
        while (n % i == 0)
            n /= i;
    }
    if (n > 1) sol = sol / n * (n - 1);
    return sol;
}

long long log(int a , int n , int mod)
{
    long long p = 1;
    while (n > 0)
    {
        if (n % 2 == 1) p = 1LL*p * a % mod;
        n /= 2;
        a = 1LL*a * a % mod;
    }
    return p;
}

int main()
{
    cout << Phi(12);
    int a , n;
    fin >> a >> n;
    fout << log(a , Phi(n) - 1 , n);
    return 0;
}