Cod sursa(job #2467812)

Utilizator tomaionutIDorando tomaionut Data 5 octombrie 2019 08:43:32
Problema Invers modular Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.63 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("inversmodular.in");
ofstream fout("inversmodular.out");
int LogP(int a, int n,int mod)
{
    int p=1;
    while (n)
    {
        if (n%2==1)
            p=1ll*p*a%mod;
        a=a*a%mod;
        n/=2;
    }
    return p;
}
int phi(int n)
{
    int sol=n,p;
    for (p=2; n>1 and 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 main()
{
    int a,n;
    fin >> a >> n;
    fout << (LogP(a,(phi(n)-1),n));




    return 0;
}