Cod sursa(job #1028670)
Utilizator | Data | 14 noiembrie 2013 15:38:45 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.28 kb |
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
char v[2000005];
int main()
{
int n,s=0;
f>>n;
for(int i=2;i<=n;i++)if(v[i]==0)for(int j=i+i;j<=n;j+=i)v[j]=1;
for(int i=2;i<=n;i++)if(v[i]==0)s++;
g<<s;
return 0;
}