Cod sursa(job #1427166)
Utilizator | Data | 1 mai 2015 17:14:59 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.3 kb |
#include <fstream>
#include <bitset>
using namespace std;
bitset<2000001> t;
int j,n,i,nr;
int main(){
ifstream fin("ciur.in");
ofstream fout("ciur.out");
fin>>n; nr=n-1;
for (i=2;i*i<=n;i++)
if (t[i]==0){
for (j=i*i;j<=n;j+=i){
if (t[j]==0) nr--; t[j]=1;
}
}
fout<<nr;
return 0;
}