Cod sursa(job #550320)
| Utilizator |  Apostol Alexandru Ionut alexapo |
Data | 9 martie 2011 13:04:35 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 30 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.3 kb |
#include<fstream.h>
ifstream f("ciur.in");
ofstream g("ciur.out");
unsigned v[2000001];
int i,j,n,p;
int main()
{
f>>n;
for(i=2;i<=n;i++)
{
if(!v[i])
for(j=i+i;j<=n;j+=i)
v[j]=1;
}
for(i=2;i<=n;i++)
if(!v[i])
p++;
g<<p<<'\n';
f.close();
f.close();
return 0;
}