Cod sursa(job #1278851)
Utilizator | Data | 29 noiembrie 2014 14:45:54 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.48 kb |
#include <fstream>
#define MAXI 2000000
using namespace std;
char v[125010];
int i,j,n,nr;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int main()
{
fin>>n;
nr=1;
for(i=3 ; i<=n ; i+=2)
{
if(! ( (int)v[i/16] & (1 << (i % 8)) ))
{
for(j=i+i ; j<=n ; j+=i)
if(!( (int)v[j/16] & (1 << (j % 8))))
v[j/16]+=1 << (j % 8);
++nr;
}
}
fout<<nr;
return 0;
}