Cod sursa(job #622118)
| Utilizator |  Sabin Olaru masterchief |
Data | 17 octombrie 2011 14:18:15 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 100 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.34 kb |
#include <cstdio>
using namespace std;
int n,i,nr = 0;
bool c[2000000];
int main(){
int N;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%d",&N);
for (int i = 2;i * i <= N;++i)
if (!c[i])
for (int j = i * i;j <= N;j += i)
c[j] = true;
for (int i = 2;i <= N;++i)
if (!c[i])
++nr;
printf ("%d",nr);
return 0;
}