Cod sursa(job #2636403)
Utilizator | Data | 17 iulie 2020 19:23:41 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.36 kb |
#include <fstream>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
bool v[2000001];
int n, nr;
int main() {
in >> n;
v[1] = 1;
for (int i = 2; i <= n; i++)
if (!v[i]) {
nr++;
for (int j = 2 * i; j <= n; j += i)
v[j] = 1;
}
out << nr;
return 0;
}