Cod sursa(job #1389282)
Utilizator | Data | 16 martie 2015 09:47:07 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include<fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
#include <fstream>
#include <math.h>
using namespace std;
int main() {
bool a[2000001];
int nr=0, n, i, j;
f>>n;
for (i=2;i<=n;i++)
a[i]=1;
for (i=2;i<=sqrt(n);i++)
if (a[i])
for (j=i;j<=n/i;j++)
a[i*j]=0;
for (i=2;i<=n;i++)
if (a[i]) nr++;
g<<nr;
g.close();
return 0;
}