Cod sursa(job #1239110)
Utilizator | Data | 8 octombrie 2014 11:30:15 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include <fstream>
using namespace std;
ifstream in ("ciur.in");
ofstream out ("ciur.out");
bool c[2000001];
int subp (int n)
{
int i,j;
for(i=2; i*i<=n; i++)
if(!c[i])
for(j=i*i; j<=n; j+=i)
c[j]=true;
}
int main()
{
int n,i,nr=0;
in>>n;
subp(n);
for(i=2; i<=n; i++)
if(!c[i])
nr++;
out<<nr<< " ";
return 0;
}