Cod sursa(job #531374)
Utilizator | Data | 9 februarie 2011 16:04:53 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.31 kb |
#include <fstream>
using namespace std;
int V[2000001],i,n,j,a;
int main()
{
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>n;
for(i=2;i<=n;i++)
{
if(V[i]==0)
{
for(j=i*2;j*j>n;j+=i)
{
V[j]=1;
}
}
}
for(i=2;i<=n;i++)
{
if(V[i]==0)
a++;
}
g<<a;
}