Cod sursa(job #2842895)
Utilizator | Albu Victor albu | Data | 1 februarie 2022 18:03:59 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.43 kb |
#include <fstream>
using namespace std;
ifstream cin("ciur.in");
ofstream cout("ciur.out");
const int NMAX=2000001;
int ciur[NMAX];
int n,nr;
int main()
{
ciur[1]=1;
ciur[0]=1;
for(int i=2;i<=NMAX;i++)
if(ciur[i]==0)
for(int j=2*i;j<=NMAX;j=j+i)
ciur[j]=1;
cin>>n;
for(int i=1;i<=n;++i)
if(ciur[i]==0)
nr++;
cout<<nr;
return 0;
}