Cod sursa(job #622101)
Utilizator | Data | 17 octombrie 2011 14:07:47 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.38 kb |
#include <fstream>
using namespace std;
bool nuprim[2000002];
int main()
{
int N,i,j,cnt=0;
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>N;
for(i=2;i*i<=N;i++)
{
if(!nuprim[i])
for(j=i*i;j<=N;j=j+i)
nuprim[j]=true;
}
for(i=2;i<=N;i++)
if(nuprim[i]==false) cnt++;
g<<cnt;
}