Cod sursa(job #1259985)
Utilizator | Curiman Andrei AndreiIT | Data | 10 noiembrie 2014 19:28:18 |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.51 kb |
#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int numere[1000005];
long long ciur(int n)
{
int i,j;
for(i=2;i<=n;i++)
{
numere[i]=i-1;
}
for(i=2;i<=n;i++)
{
for(j=2*i;j<=n;j+=i)
{
numere[j]-=numere[i];
}
}
long long total=0;
for(i=1;i<=n;i++)total+=numere[i];
total*=2;
total++;
return total;
}
int main(int n)
{
fin>>n;
fout<<ciur(n);
}