Problem p02900 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;
#define INF 1 << 30
#define endl '\n'
#define maxn 100005
#define tc printf("Case %d: ", cs)
#define tcn printf("Case %d:\n", cs);
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const double PI = acos(-1.0);

#define dbg1(x) cerr << #x << " = " << x << endl;
#define dbg2(x, y) cerr << #x << " = " << x << ", " << #y << " = " << y << endl;
#define dbg3(x, y, z)                                                          \
  cerr << #x << " = " << x << ", " << #y << " = " << y << ", " << #z << " = "  \
       << z << endl;
#define dbg4(w, x, y, z)                                                       \
  cerr << #w << " = " << w << ", " << #x << " = " << x << ", " << #y << " = "  \
       << y << ", " << #z << " = " << z << endl;

template <typename F, typename S>
ostream &operator<<(ostream &os, const pair<F, S> &p) {
  return os << "(" << p.first << ", " << p.second << ")";
}

template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "{";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  return os << "}";
}

template <typename T> ostream &operator<<(ostream &os, const set<T> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  return os << "]";
}

template <typename F, typename S>
ostream &operator<<(ostream &os, const map<F, S> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin())
      os << ", ";
    os << it->first << " = " << it->second;
  }
  return os << "]";
}

#define dbg(args...)                                                           \
  do {                                                                         \
    cerr << #args << " : ";                                                    \
    faltu(args);                                                               \
  } while (0)

clock_t tStart = clock();
#define timeStamp                                                              \
  dbg("Execution Time: ", (double)(clock() - tStart) / CLOCKS_PER_SEC)

void faltu() { cerr << endl; }

template <typename T> void faltu(T a[], int n) {
  for (int i = 0; i < n; ++i)
    cerr << a[i] << ' ';
  cerr << endl;
}

template <typename T, typename... hello>
void faltu(T arg, const hello &...rest) {
  cerr << arg << ' ';
  faltu(rest...);
}
// Program showing a policy-based data structure.
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp>
#include <functional> // for less
#include <iostream>
using namespace __gnu_pbds;
using namespace std;
// GNU link : https://goo.gl/WVDL6g
typedef tree<int, null_type, less_equal<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    new_data_set;

/**___________________________________________________**/

vector<ll> D;

void CommonDiv(ll n) {
  for (ll x = 1; x * x <= n; x++) {
    if (n % x == 0) {
      D.push_back(x);
      if (n / x != x)
        D.push_back(n / x);
    }
  }
}

int main() {
  FASTIO
  //     ///*
  // #ifndef ONLINE_JUDGE
  //     freopen("in.txt", "r", stdin);
  //     freopen("out.txt", "w", stdout);
  //     freopen("error.txt", "w", stderr);
  // #endif
  //*/
  int T;
  // scanf("%d", &T);
  T = 1;
  for (int cs = 1; cs <= T; cs++) {
    ll a, b;
    cin >> a >> b;
    ll gcd = __gcd(a, b);
    //  dbg(gcd);
    CommonDiv(gcd);

    int ans = 0;
    // for (auto x : D) cerr << x << " ";
    // cerr << endl;
    map<ll, bool> mp;
    for (int i = 0; i < (int)D.size(); i++) {
      for (int j = i + 1; j < (int)D.size(); j++) {
        if (__gcd(D[i], D[j]) > 1) {
          ll x = max(D[i], D[j]);
          mp[x] = true;
        }
      }
    }
    for (auto x : D) {
      if (!mp[x])
        ans++;
    }
    cout << ans << endl;
  }
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
#define INF 1 << 30
#define endl '\n'
#define maxn 100005
#define tc printf("Case %d: ", cs)
#define tcn printf("Case %d:\n", cs);
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const double PI = acos(-1.0);

#define dbg1(x) cerr << #x << " = " << x << endl;
#define dbg2(x, y) cerr << #x << " = " << x << ", " << #y << " = " << y << endl;
#define dbg3(x, y, z)                                                          \
  cerr << #x << " = " << x << ", " << #y << " = " << y << ", " << #z << " = "  \
       << z << endl;
#define dbg4(w, x, y, z)                                                       \
  cerr << #w << " = " << w << ", " << #x << " = " << x << ", " << #y << " = "  \
       << y << ", " << #z << " = " << z << endl;

template <typename F, typename S>
ostream &operator<<(ostream &os, const pair<F, S> &p) {
  return os << "(" << p.first << ", " << p.second << ")";
}

template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "{";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  return os << "}";
}

template <typename T> ostream &operator<<(ostream &os, const set<T> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin())
      os << ", ";
    os << *it;
  }
  return os << "]";
}

template <typename F, typename S>
ostream &operator<<(ostream &os, const map<F, S> &v) {
  os << "[";
  for (auto it = v.begin(); it != v.end(); ++it) {
    if (it != v.begin())
      os << ", ";
    os << it->first << " = " << it->second;
  }
  return os << "]";
}

#define dbg(args...)                                                           \
  do {                                                                         \
    cerr << #args << " : ";                                                    \
    faltu(args);                                                               \
  } while (0)

clock_t tStart = clock();
#define timeStamp                                                              \
  dbg("Execution Time: ", (double)(clock() - tStart) / CLOCKS_PER_SEC)

void faltu() { cerr << endl; }

template <typename T> void faltu(T a[], int n) {
  for (int i = 0; i < n; ++i)
    cerr << a[i] << ' ';
  cerr << endl;
}

template <typename T, typename... hello>
void faltu(T arg, const hello &...rest) {
  cerr << arg << ' ';
  faltu(rest...);
}
// Program showing a policy-based data structure.
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp>
#include <functional> // for less
#include <iostream>
using namespace __gnu_pbds;
using namespace std;
// GNU link : https://goo.gl/WVDL6g
typedef tree<int, null_type, less_equal<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    new_data_set;

/**___________________________________________________**/

vector<ll> D;

void CommonDiv(ll n) {
  for (ll x = 1; x * x <= n; x++) {
    if (n % x == 0) {
      D.push_back(x);
      if (n / x != x)
        D.push_back(n / x);
    }
  }
}

int main() {
  FASTIO
  //     ///*
  // #ifndef ONLINE_JUDGE
  //     freopen("in.txt", "r", stdin);
  //     freopen("out.txt", "w", stdout);
  //     freopen("error.txt", "w", stderr);
  // #endif
  //*/
  int T;
  // scanf("%d", &T);
  T = 1;
  for (int cs = 1; cs <= T; cs++) {
    ll a, b;
    cin >> a >> b;
    ll gcd = __gcd(a, b);
    //  dbg(gcd);
    CommonDiv(gcd);

    int ans = 0;
    // for (auto x : D) cerr << x << " ";
    // cerr << endl;
    map<ll, bool> mp;
    for (int i = 0; i < (int)D.size(); i++) {
      if (mp[D[i]])
        continue;
      for (int j = i + 1; j < (int)D.size(); j++) {
        if (__gcd(D[i], D[j]) > 1) {
          ll x = max(D[i], D[j]);
          mp[x] = true;
        }
      }
    }
    for (auto x : D) {
      if (!mp[x])
        ans++;
    }
    cout << ans << endl;
  }
  return 0;
}