Cod sursa(job #1919916)

Utilizator george_stelianChichirim George george_stelian Data 9 martie 2017 21:32:24
Problema Invers modular Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 0.6 kb
#include <cstdio>

using namespace std;

int mod;

int rid_put(int a,int n)
{
    int p=1;
    for(;n;n>>=1)
    {
        if(n&1) p=(1LL*p*a)%mod;
        a=(1LL*a*a)%mod;
    }
    return p;
}

int main()
{
    freopen("inversmodular.in", "r", stdin);
    freopen("inversmodular.out", "w", stdout);
    int a,n;
    scanf("%d%d",&a,&n);
    mod=n;
    int phi=mod;
    for(int i=2;i<=n;i++)
        if(n%i==0)
        {
            phi=(phi/i)*(i-1);
            for(;n%i==0;n/=i);
        }
    if(n>1) phi=(phi/n)*(n-1);
    printf("%d",rid_put(a,phi-1));
    return 0;
}