Cod sursa(job #2456302)

Utilizator pishcotMiruna Turbatu pishcot Data 14 septembrie 2019 10:25:05
Problema Invers modular Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.72 kb
#include <bits/stdc++.h>

using namespace std;

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

int a , n;

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

int lgput(int a, int n, int modulo)
{
    int p = 1;
    while(n)
    {
        if(n % 2 == 1) p = 1LL * p * a % modulo;
        n /= 2;
        a = 1LL * a * a % modulo;
    }
    return p;

}


int main()
{
    int b;
    fin >> a >> n;
    b = lgput(a, phi(n) - 1, n);
    fout << b;
    return 0;
}