Cod sursa(job #2513187)
Utilizator | Alexandru Toma alextm | Data | 22 decembrie 2019 15:14:02 |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.45 kb |
#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int euler[1000002], i, j, N, sol = 0;
int main()
{
fin >> N;
for(i = 1; i <= N; i++)
euler[i] = i - 1;
for(i = 2; i <= N; i++)
for(j = i + i; j <= N; j += i)
euler[j] = euler[j] - euler[i];
for(i = 1; i <= N; i++)
sol = sol + euler[i];
fout << sol * 2 + 1;
return 0;
}