Cod sursa(job #942129)
Utilizator | Linca Robert robx12ln | Data | 20 aprilie 2013 22:26:23 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include<fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n,i,k,c;
char v[2000001];
int main(){
fin>>n;
c=0;
for(i=2;i<=n;i++){
if(v[i]==0){
c++;
for(k=i+i;k<=n;k+=i)
v[k]=1;
}
}
fout<<c<<"\n";
return 0;
}