Cod sursa(job #1418100)
Utilizator | Data | 11 aprilie 2015 21:52:29 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.36 kb |
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int i,j,n,nr=0;
bool v[2000001]= {0};
int main()
{
v[0]=v[1]=1;
for(i=2; i<=1000000; i++)
if(!v[i])
{
for(j=i*2; j<=2000000; j+=i)
v[j]=1;
}
f>>n;
for(i=2;i<=n;i++)
if(v[i]==0)nr++;
g<<nr;
}