Cod sursa(job #493508)
Utilizator | George Marcus PlayLikeNeverB4 | Data | 18 octombrie 2010 17:13:03 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.34 kb |
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
const int MAX=2000001;
char prim[MAX];
int N,S=0;
int main()
{
int i,j;
fin >> N;
for(i=2;i<=N;i++) prim[i]=1;
for(i=2;i<=N;i++)
if(prim[i]==1)
{
for(j=2;i*j<=N; j++)
prim[i*j]=0;
S++;
}
fout << S;
}