Cod sursa(job #1880029)
Utilizator | Data | 15 februarie 2017 12:59:03 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.43 kb |
#include <bits/stdc++.h>
#define NMax 2000005
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int N,nr;
bool isPrim[NMax];
int main()
{
fin>>N;
for(int i=2;i<=N;i++)
isPrim[i]=true;
for(int i=2;i<=N;i++)
if(isPrim[i])
{
nr++;
for(int j=i+i;j<=N;j+=i)
isPrim[j]=false;
}
fout<<nr;
return 0;
}