Cod sursa(job #664984)
| Utilizator |  Macovei Claudiu nutipasa16 |
Data | 21 ianuarie 2012 13:03:40 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 0 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.33 kb |
#include<fstream.h>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n,x,nr,v[2000001];
int prim(int x)
{for(int d=2;d<x/2;d++)if(x%d==0)return 0;
return 1;
}
int main()
{f>>n;
while(x*6<n){if(prim(x*6-1))nr++;
if(prim(x*6+1))nr++;
x++;
}
g<<nr<<" ";
g.close();
return 0;
}