Cod sursa(job #2900817)

Utilizator alexdumitruAlexandru Dumitru alexdumitru Data 12 mai 2022 10:53:53
Problema Invers modular Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.66 kb
#include <bits/stdc++.h>
using namespace std;

long long  x,mod;

long long  lgput(long long  a, long long  b)
{
    long long  r=1;
    while(b>0)
    {
        if(b&1)
            r=(r*a)%mod;
        a=(a*a)%mod;
        b>>=1;
    }
    return r;
}

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

int phi(int n)
{
    int r=n,d=2;
    while(n>1)
    {
        if(n%d==0)
        {
            r=r/d*(d-1);
            while(n%d==0)n/=d;
        }
        d++;
        if(d*d>n)
            d=n;
    }
    return r;
}

signed main()
{
    fin>>x>>mod;
    fout<<lgput(x,phi(mod)-1)<<'\n';
    return 0;
}