Cod sursa(job #692622)

Utilizator DevastatorMarius Adelin Devastator Data 26 februarie 2012 17:40:49
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>
FILE *f=fopen("fractii.in","r");
FILE *g=fopen("fractii.out","w");
long long int n,i,j,k=0,v[1000001]; 
int main()
{
	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-1)/i;
	for(i=2;i<=n;i++) k+=v[i];
	fprintf(g,"%lld",2*k+1);
	return 0;
}