Cod sursa(job #821324)
Utilizator | Data | 22 noiembrie 2012 09:24:09 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.35 kb |
#include<iostream>
#include<fstream>
using namespace std;
#define MAX_N 2000000
long n, contor;
int v[MAX_N];
int main(){
ifstream fin ("ciur.in");
ofstream fout ("ciur.out");
fin >> n;
for(int i=2; i<=n; i++){
if(!v[i]){
contor ++;
for(int j=i; j<=n; j+= i)
v[j] = 1;
}
}
fout << contor ;
return 0;
}