Cod sursa(job #1200328)
Utilizator | Data | 22 iunie 2014 09:47:55 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.31 kb |
#include<fstream>
#include<bitset>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
const int Nmax=2000001;
int n,nr,i,j;
bitset <Nmax> a;
int main()
{ f>>n;
for(i=2;i<=n;i++)
if(!a[i])
{ nr++;
for(j=i+i;j<=n;j+=i) a[j]=1;
}
g<<nr<<"\n";
g.close();
return 0;
}