Cod sursa(job #3227180)
Utilizator | Data | 26 aprilie 2024 18:55:34 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.37 kb |
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n,nr,i,j;
bool v[2000001];
int main()
{
fin>>n;
for(i=3; i*i<=n; i+=2)
if(v[i]==0)
for(j=3; j<=n/i; j+=2)
v[i*j]=1;
nr=1;
for(i=3; i<=n; i+=2)
if(v[i]==0)
nr++;
fout<<nr;
return 0;
}