Cod sursa(job #783630)
Utilizator | Data | 3 septembrie 2012 14:58:06 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.31 kb |
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n,v[2000000],t;
void ciur()
{int i,j;
t=1;
for(i=3;i<=n;i+=2)
{v[i+1]=1;
if(v[i]==0)
{
for(j=2*i;j<=n;j+=i)
v[j]=1;
t++;
}
}
}
int main()
{f>>n;
ciur();
g<<t;
return 0;
}