Cod sursa(job #2122384)
Utilizator | Data | 4 februarie 2018 23:40:48 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.38 kb |
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n, x[2000005], i, j, nr=1;
int main()
{
fin >> n;
for (i=3; i<=n; i++)
{
if (x[i] == 0 && i%2==1)
{
nr++;
for (j=i+i+i; j<=n; j+=i+i)
x[j]=1;
}
}
fout << nr;
return 0;
}