Cod sursa(job #283901)
Utilizator | Banu Lavinia Luffy | Data | 20 martie 2009 16:53:09 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.32 kb |
#include<fstream>
using namespace std;
int a[2000000];
int main()
{unsigned long n,i,j,nr=0;
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>n;
for(i=2;i*i<=n;i++)
if(a[i]==0)
for(j=2;i*j<=n;j++)
if(a[i*j]==0) {nr++; a[i*j]=1;}
g<<n-nr-1<<'\n';
f.close();
g.close();
return 0;
}