Cod sursa(job #894523)
Utilizator | Data | 26 februarie 2013 21:47:44 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 90 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.4 kb |
#include <fstream>
#include <vector>
using std::vector;
std::ifstream in("ciur.in");
std::ofstream out("ciur.out");
vector <char> a;
int main()
{
int N;
in >> N;
a.resize(N,1);
int cnt = 0;
for (int i = 2; i <= N; i++)
if (a[i] == 1)
{
cnt++;
for (int j = i+i; j <= N; j += i)
a[j] = 0;
}
out << cnt;
return 0;
}