Cod sursa(job #920685)
Utilizator | Data | 20 martie 2013 16:26:35 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.44 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n, a[2000001], i, j, nr;
int main()
{
nr=1;
f>>n;
for(i=3; i<=n; i+=2)
{
if(a[i]==0)
{
nr++;
for(j=3*i; j<=n; j+=i)
a[j]=1;
}
}
g<<nr;
f.close();
g.close();
return 0;
}