Cod sursa(job #420879)

Utilizator drywaterLazar Vlad drywater Data 20 martie 2010 18:29:31
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include <stdio.h>
FILE *f=fopen("fractii.in","r"),*g=fopen("fractii.out","w");
int n,i,x[1000001],j;
long long nr;

int main(void)
{
	fscanf(f,"%d",&n);
	for (i=2;i<=n;i++)
	{
		x[i]=i-1;
	}
	for (i=2;i<=n;i++)
	{
		nr=nr+x[i];
		for (j=i*2;j<=n;j=j+i)
			x[j]=x[j]-x[i];
	}
	nr=nr*2+1;
	fprintf(g,"%lld",nr);
	fclose(g);
	return 0;
}