Cod sursa(job #1470050)
Utilizator | Data | 10 august 2015 12:27:15 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.31 kb |
#include <fstream>
using namespace std;
ifstream fi("ciur.in");
ofstream fo("ciur.out");
int s,i,n,j;
bool prim[2000009];
int main()
{ fi>>n;
for(i=2;i<=n;i++)
if (prim[i]==0) for(j=i*2;j<=n;j+=i)
prim[j]=1;
for(i=2;i<=n;i++)
if (prim[i]==0) s++;
fo<<s;
return 0;
}