Cod sursa(job #1625269)
Utilizator | Data | 2 martie 2016 17:53:24 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include<fstream>
using namespace std;
ifstream in ("ciur.in");
ofstream out ("ciur.out");
int n,o;
bool v[2000005];
int main(){
in>>n;
for(int i=2;i<=n;i++)
v[i]=true;
for(int i=2;i<=n;i++)
if(v[i]==1){
o++;
for(int j=i*i;j<=n;j+=i)
v[j]=false;
}
out<<o;
out.close();
return 0;
}