Cod sursa(job #420869)

Utilizator samuel91Asofronie Samuel samuel91 Data 20 martie 2010 18:12:44
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.32 kb
Raporteaza aceasta sursa 
#include <fstream> 
using namespace std;
long long n,x[1000005],i,j,S=0; 
int main() 
{ 
ifstream f("fractii.in"); 
ofstream g("fractii.out"); 
f>>n; 
for(i=2;i<=n;i++) 
x[i]=i-1; 
for(i=2;i<=n;i++) 
{ 
S=S+x[i]; 
for(j=i*2;j<=n;j=j+i) 
x[j]=x[j]-x[i]; 
} 
S=S*2+1; 
g<<S; 
f.close(); 
g.close(); 
return 0; 
}