Cod sursa(job #827949)
Utilizator | FMI Calinescu Valentin Gelu Vally77 | Data | 2 decembrie 2012 20:35:18 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.53 kb |
#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;
long long int i,g,n,prime[2000005],s;
int main()
{
ifstream ka("ciur.in");
ofstream ki("ciur.out");
ka>>n;
for(i=2;i<n;i++)
{
prime[i]=1;
}
for(i=2;i<=sqrt(n);i++)
{
if(prime[i]==1)
{
for(g=i*i;g<=n;g+=i)
{
prime[g]=0;
}
}
}
for(int i=2;i<n;i++)
{
if(prime[i]==1)
s++;
}
ki<<s;
}