Cod sursa(job #2135463)
Utilizator | Data | 18 februarie 2018 21:01:26 | |
---|---|---|---|
Problema | Invers modular | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.58 kb |
#include <fstream>
using namespace std;
ifstream cin("inversmodular.in");
ofstream cout("inversmodular.out");
long long a,n,p;
long long fi(int n) {
long long r=n;
for (int i=2; i*i<=n; i++)
if (n % i == 0)
{
while(n%i==0) n/=i;
r-=r/i;
}
if (n!=1) r-=r/n;
return r;
}
long long rid(long long a, long long b) {
if (b==0) return 1;
long long x=rid(a,b/2);
if (b%2) return x*x%n*a%n;
return x*x%n;
}
int main()
{
cin>>a>>n;
p=fi(n)-1;
cout<<rid(a,p);
return 0;
}