Cod sursa(job #1364748)
Utilizator | Data | 27 februarie 2015 20:01:44 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.35 kb |
#define N 2000001
#include <fstream>
using namespace std;
ifstream cin("ciur.in");
ofstream cout("ciur.out");
int main()
{
bool ciur[N];
int n,i,j,k=0;
cin>>n;
for(i=1;i<=n;i++)
ciur[i]=true;
for(i=2;i<=n;i++)
if(ciur[i]==true)
{k++;
for(j=i+i;j<=n;j=j+i)
ciur[j]=false;}
cout<<k;
return 0;
}