Cod sursa(job #1985087)
Utilizator | Vulsan Bianca Maria BiancaMariaVulsan | Data | 26 mai 2017 20:57:27 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
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");
bool v[2000005]; //pres ca toate nr sunt prime
int main()
{
int i,j,n,nr=1;
f>>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
}
}
g<<nr;
f.close();
g.close();
return 0;
}