Cod sursa(job #200328)

Utilizator ghiutaalexGhiuta Alex ghiutaalex Data 23 iulie 2008 13:36:47
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.34 kb
Raporteaza aceasta sursa 
#include<stdio.h>
long long n,s,i,j,v[1000001];
int main()
{FILE*f=fopen("fractii.in","r");
 FILE*g=fopen("fractii.out","w");
 fscanf(f,"%lld",&n);
 for(i=1;i<=n;i++)
	v[i]=i;
 for(i=2;i<=n;i++)
	if(v[i]==i) for(j=i;j<=n;j+=i)
			v[j]=v[j]/i*(i-1);
 for(i=2;i<=n;i++)
 	s+=2*v[i]; 
 fprintf(g,"%lld",s+1);
 fcloseall();
 return 0;
}