Cod sursa(job #980524)
Utilizator | Data | 4 august 2013 20:56:28 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.37 kb |
#include <fstream>
#include <cmath>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
bool v[2000001];
int main ()
{
unsigned long long n,i,j,s=0;
fin>>n;
for(i=2;i<=n;i++)
{
if(v[i]==0)
{
s++;
for(j=i*i;j<=n;j+=i)
v[j]=1;
}
}
fout<<s;
}