Cod sursa(job #2861880)
Utilizator | Mihaescu Vlad-Mihai Toaster_Keyboard | Data | 4 martie 2022 17:08:06 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <iostream>
using namespace std;
//#define ll long long
bool ciur[2000005];
int main() {
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
int n; scanf("%d", &n);
ciur[0] = ciur[1] = true;
int cnt = 0;
for (int i = 2; i <= n; i++) {
if (i <= n && ciur[i] == false)
++cnt;
for (int j = 2; i * j <= n; j++)
ciur[i * j] = true;
}
printf("%d", cnt);
fclose(stdin);
fclose(stdout);
return 0;
}