Cod sursa(job #1280284)
Utilizator | Data | 1 decembrie 2014 18:30:44 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.28 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
int p[2000001];
int main()
{long n,nr=0,j,i;
in>>n;
for(i=2;i<=n;i++)
if(p[i]==0){nr++;
for(j=i+i;j<=n;j+=i)
p[j]=1;
}
out<<nr;
return 0;
}