Cod sursa(job #2497041)
Utilizator | Data | 21 noiembrie 2019 23:27:35 | |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.64 kb |
#include <fstream>
unsigned N;
unsigned long S = 1;
unsigned phi(unsigned n)
{
unsigned result = n, p = 2;
while (p * p <= n)
{
while (n % p == 0)
{
n /= p;
}
result -= result / p;
++p;
}
if (n > 1)
{
result -= result / n;
}
return result;
}
int main()
{
std::ifstream fisierIN("fractii.in");
fisierIN >> N;
fisierIN.close();
for (unsigned k = 2; k <= N; ++k)
{
S += 2 * phi(k);
}
std::ofstream fisierOUT("fractii.out");
fisierOUT << S;
fisierOUT.close();
return 0;
}