Open devLupin opened 1 year ago
#include <cmath> using namespace std; bool arr[1000001]; int eratos(int n) { fill_n(arr, n, true); for(int i=2; i<=sqrt(n); i++) { if(!arr[i]) continue; for(int j=i*i; j<=n; j += i) arr[j] = false; } int ans = 0; for(int i=2; i<=n; i++) if(arr[i]) ans++; return ans; }
num
true
using ll = long long; bool is_prime(ll num) { if(num < 2) return false; for(int i=2; i<=sqrt(num); ++i) { if(num % i == 0) return false; } return true; }
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