Cod sursa(job #2467812)
| Utilizator | 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;
}
