Cod sursa(job #1723538)
Utilizator | Data | 30 iunie 2016 21:55:36 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.41 kb |
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin ("ciur.in");
ofstream fout ("ciur.out");
int n;
int k = 0;
vector<int> sieve;
int main(){
fin>>n;
sieve.resize(n+1);
for (int i = 2; i <= n; ++i)
sieve[i] = 1;
for (int i = 2; i <= n; ++i)
{
if (sieve[i])
{
k++;
for (int j = i + i; j <= n; j += i)
{
sieve[j] = 0;
}
}
}
fout<<k;
return 0;
}