Cod sursa(job #1088626)
Utilizator | Data | 20 ianuarie 2014 17:50:03 | |
---|---|---|---|
Problema | Invers modular | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.47 kb |
#include<fstream>
using namespace std;
ifstream f("inversmodular.in");
ofstream g("inversmodular.out");
long long a,n,phi=1,i,b,r,p;
int main()
{
f>>a>>n;
p=n;
for(i=2;i*i<=n;i++)
if(n%i==0)
{
while(!(n%i)) {n/=i; phi*=i;}
phi/=i; phi*=(i-1);
}
if(n>1) phi*=n-1;
b=phi-1;
r=1;
for(i=1;i<=b;i<<=1)
{
if(i&b) r=(r*a)%p;
a=(a*a)%p;
}
g<<r;
return 0;
}