Cod sursa(job #1985085)
Utilizator | Vulsan Bianca Maria BiancaMariaVulsan | Data | 26 mai 2017 20:51:59 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.46 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int v[2000000],nr=1; //pres ca toate nr sunt prime
int main()
{
int i,j,n;
cin>>n;
for(i=3; i<=n; i+=2)
{
if(v[i]==0) //daca i e prim
{nr++;
for(j=3; i*j<=n; j++) v[i*j]=1;//eliminam toti multiplii lui
}
}
cout<<nr;
f.close();
g.close();
return 0;
}