Cod sursa(job #1929048)

Utilizator alex273Groza Alexandru alex273 Data 16 martie 2017 23:46:24
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include  <fstream>
 using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
int v[1000001];
int main ()
{
 long long suma=0;
int n;
f>>n;
for (int i=1;i <=n;++i)
v[i]=i-1;
for (int i=2;i <=n;++i)
for (int j=2*i;j <=n;j+=i)
v[j]-=v[i];
for (int j=1;j <=n;++j)
suma+=v[j];
suma=suma*2;suma=suma+1;
g<<suma;
return 0; 
}