Problem p02642 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;
#define rep(i, N) for (int i = 0; i < int(N); ++i)
#define rep1(i, N) for (int i = 1; i < int(N); ++i)
#define all(a) (a).begin(), (a).end()
#define print(v)                                                               \
  {                                                                            \
    cerr << #v << ": [ ";                                                      \
    for (auto _ : v)                                                           \
      cerr << _ << ", ";                                                       \
    cerr << "]" << endl;                                                       \
  }
#define printpair(v)                                                           \
  {                                                                            \
    cerr << #v << ": [ ";                                                      \
    for (auto _ : v)                                                           \
      cerr << "{" << _.first << "," << _.second << "}"                         \
           << ", ";                                                            \
    cerr << "]" << endl;                                                       \
  }
#define dump(x) cerr << #x << ": " << x << endl;
#define bit(k) (1LL << (k))
typedef long long ll;
typedef pair<int, int> i_i;
typedef pair<ll, ll> l_l;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vec<T>>;
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << "{" << p.first << ", " << p.second << "}";
  return os;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

const int INF = (ll)1e9;
const ll INFLL = (ll)1e18 + 1;
const ll MOD = (ll)1e9 + 7;
const double PI = acos(-1.0);
/*
const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const string dir = "DRUL";
*/

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(20);

  int N;
  cin >> N;
  vector<ll> A(N);
  vector<ll> cnt(1000100, 0);
  vector<bool> ok(1000100, true);
  rep(i, N) {
    cin >> A[i];
    cnt[A[i]]++;
  }
  sort(all(A));
  int ans = 0;
  rep(i, N) {
    if (cnt[A[i]] == 1 && ok[A[i]])
      ans++;
    for (int j = A[i]; j <= 1000000; j += A[i]) {
      ok[j] = false;
    }
  }
  cout << ans << endl;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
#define rep(i, N) for (int i = 0; i < int(N); ++i)
#define rep1(i, N) for (int i = 1; i < int(N); ++i)
#define all(a) (a).begin(), (a).end()
#define print(v)                                                               \
  {                                                                            \
    cerr << #v << ": [ ";                                                      \
    for (auto _ : v)                                                           \
      cerr << _ << ", ";                                                       \
    cerr << "]" << endl;                                                       \
  }
#define printpair(v)                                                           \
  {                                                                            \
    cerr << #v << ": [ ";                                                      \
    for (auto _ : v)                                                           \
      cerr << "{" << _.first << "," << _.second << "}"                         \
           << ", ";                                                            \
    cerr << "]" << endl;                                                       \
  }
#define dump(x) cerr << #x << ": " << x << endl;
#define bit(k) (1LL << (k))
typedef long long ll;
typedef pair<int, int> i_i;
typedef pair<ll, ll> l_l;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vec<T>>;
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << "{" << p.first << ", " << p.second << "}";
  return os;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

const int INF = (ll)1e9;
const ll INFLL = (ll)1e18 + 1;
const ll MOD = (ll)1e9 + 7;
const double PI = acos(-1.0);
/*
const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const string dir = "DRUL";
*/

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(20);

  int N;
  cin >> N;
  vector<ll> A(N);
  vector<ll> cnt(1000100, 0);
  vector<bool> ok(1000100, true);
  rep(i, N) {
    cin >> A[i];
    cnt[A[i]]++;
  }
  sort(all(A));
  int ans = 0;
  rep(i, N) {
    if (cnt[A[i]] == 1 && ok[A[i]])
      ans++;
    if (!ok[A[i]])
      continue;
    for (int j = A[i]; j <= 1000000; j += A[i]) {
      ok[j] = false;
    }
  }
  cout << ans << endl;
}