Cod sursa(job #1919449)
Utilizator | Data | 9 martie 2017 19:31:32 | |
---|---|---|---|
Problema | Invers modular | Scor | 50 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.71 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("inversmodular.in");
ofstream g("inversmodular.out");
long long n, m;
long long phi(long long nr)
{
long long crt=nr;
for(long long i=2; i*i<=nr; ++i)
{
if(nr%i==0)
{
while(nr%i==0)
{
nr/=i;
}
crt=(crt/i)*(i-1);
}
}
if(nr!=1)
{
crt=(crt/nr)*(nr-1);
}
return crt;
}
int main()
{
f>>n>>m;
long long p=phi(m)-1, crt=1;
for(int i=1; i<=p; i<<=1)
{
if(i&p)
{
crt=(crt*n)%m;
}
n=(n*n)%m;
}
g<<crt;
return 0;
}