Cod sursa(job #1884892)
Utilizator | Data | 19 februarie 2017 14:08:28 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include <fstream>
#include <bitset>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
const int N = 2000005;
int n, c=0;
bitset<N> v;
int main()
{
fin>>n;
for(int i=2;i<=n;i++)
if(!v.test(i))
{
c++;
for(long long j=i*i;j<=n;j+=i)
v.set(j);
}
fout<<c;
return 0;
}