Cod sursa(job #1039833)
| Utilizator |  Alexia Ambrus alexiaambrus |
Data | 23 noiembrie 2013 17:16:36 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 100 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.33 kb |
#include <fstream>
#include <cmath>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n, r, i, nr, j, k;
char v[2000005];
int main()
{f>>n;
r= sqrt(n);
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]!=1)
nr++;
g<<nr<<'\n';
return 0;
}
