Cod sursa(job #779473)
Utilizator | Data | 17 august 2012 19:29:38 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.37 kb |
#include <fstream>
#define MAXN 2000004
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
long n,cnt;
bool uz[MAXN];
int main()
{
long i,j;
f>>n;
for(i=2;i<=n;i++){
if(!uz[i]){
++cnt;
for(j=i;j<=n;j+=i)
uz[j]=1;}}
g<<cnt<<'\n';
f.close();
g.close();
return 0;
}