Cod sursa(job #2756680)

Utilizator matei.balaur2009Matei Balaur12 matei.balaur2009 Data 2 iunie 2021 12:13:05
Problema Invers modular Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.74 kb
#include <fstream>

using namespace std;
ifstream in("inversmodular.in");
ofstream out("inversmodular.out");
int a,n;
int euler(int x) {
    int e=1;
    if(x%2==0) {
        x/=2;
        while(x%2==0) {
            x/=2;
            e*=2;
        }
    }
    for(int d=3; d*d<=x; d+=3)
        if(x%d==0) {
            x/=d;
            e*=d-1;
            while(x%d==0) {
                x/=d;
                e*=d;
            }
        }
    if(x>1)
        e*=x-1;
    return e;
}
int putere(int b,int e) {
    if(e==0)
        return 1;
    int r=putere(b,e/2);
    r=1LL*r*r%n;
    if(e%2==1)
        r=1LL*r*b%n;
    return r;

}
int main() {
    in>>a>>n;
    out<<putere(a,euler(n)-1);
    return 0;
}