Problem p02574 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n) for (int i = 1; i <= (int)(n); i++)
#define drep(i, n) for (int i = (n)-1; i >= 0; i--)
#define ALL(x) (x).begin(), (x).end()
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

// Mod int
const int mod = 1000000007;
// const int mod = 998244353;
struct mint {
  ll x;
  mint() : x(0) {}
  mint(ll x) : x((x % mod + mod) % mod) {}
  // mint(ll x):x(x){}
  mint &fix() {
    x = (x % mod + mod) % mod;
    return *this;
  }
  mint operator-() const { return mint(0) - *this; }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator-=(const mint &a) {
    if ((x += mod - a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint &a) const { return mint(*this) += a; }
  mint operator-(const mint &a) const { return mint(*this) -= a; }
  mint operator*(const mint &a) const { return mint(*this) *= a; }
  bool operator<(const mint &a) const { return x < a.x; }
  bool operator==(const mint &a) const { return x == a.x; }
};
istream &operator>>(istream &i, mint &a) {
  i >> a.x;
  return i;
}
ostream &operator<<(ostream &o, const mint &a) {
  o << a.x;
  return o;
}
//

int gcd(int a, int b) {
  if (a % b == 0)
    return b;
  else
    return gcd(b, a % b);
}

int main() {
  int n;
  cin >> n;
  vi a(n), c(1000005);
  rep(i, n) {
    cin >> a[i];
    c[a[i]]++;
  }

  bool ok = true;
  for (int i = 2; i < 1000005; i++) {
    int cnt = 0;
    for (int j = i; j < 1000005; j += i)
      cnt += c[j];
    if (cnt > 1)
      ok = false;
  }
  if (ok) {
    cout << "pairwise coprime" << endl;
    return 0;
  }

  int x = a[0];
  rrep(i, n - 1) x = gcd(x, a[i]);
  if (x == 1) {
    cout << "setwise coprime" << endl;
    return 0;
  }

  cout << "not coprime" << endl;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n) for (int i = 1; i <= (int)(n); i++)
#define drep(i, n) for (int i = (n)-1; i >= 0; i--)
#define ALL(x) (x).begin(), (x).end()
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

// Mod int
const int mod = 1000000007;
// const int mod = 998244353;
struct mint {
  ll x;
  mint() : x(0) {}
  mint(ll x) : x((x % mod + mod) % mod) {}
  // mint(ll x):x(x){}
  mint &fix() {
    x = (x % mod + mod) % mod;
    return *this;
  }
  mint operator-() const { return mint(0) - *this; }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator-=(const mint &a) {
    if ((x += mod - a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint &a) const { return mint(*this) += a; }
  mint operator-(const mint &a) const { return mint(*this) -= a; }
  mint operator*(const mint &a) const { return mint(*this) *= a; }
  bool operator<(const mint &a) const { return x < a.x; }
  bool operator==(const mint &a) const { return x == a.x; }
};
istream &operator>>(istream &i, mint &a) {
  i >> a.x;
  return i;
}
ostream &operator<<(ostream &o, const mint &a) {
  o << a.x;
  return o;
}
//

int d[1000005];

void f(int n) {
  for (int i = 1; i * i <= n; i++) {
    if (n % i == 0) {
      d[i]++;
      if (i * i != n)
        d[n / i]++;
    }
  }
}

int gcd(int a, int b) {
  if (a % b == 0)
    return b;
  else
    return gcd(b, a % b);
}

int main() {
  int n;
  cin >> n;
  vi a(n);
  rep(i, n) cin >> a[i];
  rep(i, n) f(a[i]);
  d[1] = 0;
  bool ok1 = true;
  rep(i, 1000005) if (d[i] > 1) ok1 = false;
  if (ok1) {
    cout << "pairwise coprime" << endl;
    return 0;
  }

  int x = a[0];
  rrep(i, n - 1) x = gcd(x, a[i]);
  if (x == 1) {
    cout << "setwise coprime" << endl;
    return 0;
  }

  cout << "not coprime" << endl;
}