Cod sursa(job #505247)
Utilizator | Naomi Ionescu SpaceRealm | Data | 1 decembrie 2010 10:01:53 |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.41 kb |
#include<iostream.h>
#include<fstream.h>
ifstream f("fractii.in");
ofstream g("fractii.out");
int n,phi[1000001];
int main()
{
int i,j,c=0;
f>>n;
for(i=1;i<=n;i++)
phi[i]=i-1;
for(i=2;i<=n;i++)
for(j=2*i;j<=n;j+=i)
phi[j]-=phi[i];
for(i=1;i<=n;i++)
phi[i]=i-1;
for(i=2;i<=n;i++)
for(j=2*i;j<=n;j+=i)
phi[j]-=phi[i];
for(i=1;i<=n;i++)
c+=phi[i];
c=2*c+1;
g<<c;
return 0;
}