Cod sursa(job #1416922)
Utilizator | Data | 9 aprilie 2015 09:23:57 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.64 kb |
#include <fstream>
#define NMAX 1000005
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
unsigned long long n , i , v[NMAX] , j , sum;
int main()
{
f>>n;
for(i=1;i<=n;i++)
{
if(v[i]==0)
{
v[i]=i-1;
for(j=i*2;j<=n;j+=i)
{
if(v[j]==0)
{
v[j]=j*(i-1)/i;
}
else
{
v[j]=v[j]*(i-1)/i;
}
}
}
}
for(i=2;i<=n;i++)
{
sum+=v[i];
}
g<<sum*2+1;
return 0;
}