Cod sursa(job #2010042)
Utilizator | Data | 11 august 2017 16:41:48 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int prim[2000001];
int main()
{
int n,i,j,ct;
fin>>n;
ct=0;
for(i=3;i<=n;i+=2)
if(prim[i]==0)
{ct++;
for(j=i*3;j<=n;j+=i)
prim[i]=1;
}
fout<<ct;
return 0;
}