Cod sursa(job #1039813)
| Utilizator |  Alexia Ambrus alexiaambrus |
Data | 23 noiembrie 2013 17:07:27 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 30 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.32 kb |
#include <fstream>
#include <cmath>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n, r, i, nr, j, k, v[2000001];
int main()
{f>>n;
r= sqrt(n)+1;
for(i= 2; i<=r; i++)
if(v[i]==0)
for(j= i*i; j<=n; j= j+i)
v[j]= 1;
nr= 0;
for(k= 2; k<=n; k++)
if(v[k]==0)
nr++;
g<<nr<<'\n';
return 0;
}
