Cod sursa(job #1009434)
Utilizator | Data | 13 octombrie 2013 09:22:01 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.4 kb |
#include<fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
bool prim[2000005];
int n,i,j,x;
int main()
{
fin >> n;
for (i=2; i<=n; i++)
prim[i]=1;
for (i=2; i<=n; i++)
{
if (prim[i])
{
x++;
for (j=i+i; j<=n; j+=i)
prim[j]=0;
}
}
fout << x;
return 0;
}