Cod sursa(job #1468458)
Utilizator | Data | 6 august 2015 09:31:41 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.5 kb |
#include <iostream>
#include <fstream>
using namespace std;
int cnt,c[2000001];
int main()
{
ifstream cin ("ciur.in");
ofstream cout ("ciur.out");
int i, j;
int n;
cin>>n;
for ( i = 2; i*i <= n; ++i)
{
if (c[i] == 0)
{
for (j = i*i; j <= n; j += i)
{
c[j] = 1;
}
}
}
for(i=0;i<n;i++)
{
if(c[i]==1)
cnt++;
}
cout<<cnt;
return 0;
}