Cod sursa(job #209961)
Utilizator | Albu Alexandru albua | Data | 25 septembrie 2008 20:29:32 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | c | Status | done |
Runda | Arhiva de probleme | Marime | 0.5 kb |
#include <stdio.h>
FILE *f,*g;
long i,j,n,npedoi,temp;
char a[1000000];
long long contor;
int main()
{
f=fopen("fractii.in","r");
g=fopen("fractii.out","w");
fscanf(f,"%ld\n",&n);
contor=n*n-n+1;
npedoi=n/2;
if(n%2==1)
npedoi++;
for(i=2;i<=npedoi;i++)
if(a[i]!=1)
{
temp=0;
for(j=2;i*j<=n;j++)
{
contor-=2;
temp++;
a[i*j]=1;
}
contor-=temp*(temp-1);
}
fprintf(g,"%lld\n",contor);
fclose(f); fclose(g);
return 0;
}