Cod sursa(job #1816962)
Utilizator | Data | 27 noiembrie 2016 10:52:43 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.3 kb |
#include <fstream>
using namespace std;
int n,nr,i,j;
bool ciur[20000001];
int main()
{
ifstream cin("ciur.in");
ofstream cout("ciur.out");
cin>>n;
nr=0;
for(i=2;i<=n;i++)
if(ciur[i]==0){
nr++;
for(j=i+i;j<=n;j=j+i)
ciur[j]=1;
}
cout<<nr;
return 0;
}