Cod sursa(job #1681117)
Utilizator | Data | 9 aprilie 2016 11:40:34 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.38 kb |
#include<iostream>
#include<fstream>
using namespace std;
bool a[2000003];
int main()
{
ifstream f("ciur.in");
ofstream g("ciur.out");
int i,j,n,nr=0;
f>>n;
for(i=2;i<=n/2;i++)
for(j=i*i;j<=n;j=j+i)
a[j]=1;
for(i=2;i<=n;i++)
if(a[i]==0)
nr++;
g<<nr;
f.close();
g.close();
return 0;
}