Problem p02900 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
#include <unistd.h>

using namespace std;
#define DEBUG(x) cerr << #x << ": " << x << endl;
#define DEBUG_VEC(v)                                                           \
  cerr << #v << ":";                                                           \
  for (int i = 0; i < v.size(); i++)                                           \
    cerr << " " << v[i];                                                       \
  cerr << endl
#define DEBUG_MAT(v)                                                           \
  cerr << #v << endl;                                                          \
  for (int i = 0; i < v.size(); i++) {                                         \
    for (int j = 0; j < v[i].size(); j++) {                                    \
      cerr << v[i][j] << " ";                                                  \
    }                                                                          \
    cerr << endl;                                                              \
  }
typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define vs vector<string>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
template <class S, class T>
pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first + t.first, s.second + t.second);
}
template <class S, class T>
pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first - t.first, s.second - t.second);
}
template <class S, class T> ostream &operator<<(ostream &os, pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
#define X first
#define Y second
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
#define rrep1(i, n) for (int i = (n); i > 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(), c.end()
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const ll MOD = 1000000007;
// const ll MOD = 998244353;
const double pi = 3.14159265358979323846;
#define Sp(p) cout << setprecision(15) << fixed << p << endl;
int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
int dx2[8] = {1, 1, 0, -1, -1, -1, 0, 1}, dy2[8] = {0, 1, 1, 1, 0, -1, -1, -1};
#define fio()                                                                  \
  cin.tie(0);                                                                  \
  ios::sync_with_stdio(false);
// #define mp make_pair
// #define endl '\n'

ll gcd(ll a, ll b) {
  if (b > a) {
    swap(a, b);
  }
  ll r = a % b;
  while (r != 0) {
    a = b;
    b = r;
    r = a % b;
  }
  return b;
}

int main() {
  ll a, b;
  cin >> a >> b;

  vl kou;
  for (ll i = 1; i * i <= a; i++) {
    if (a % i == 0) {
      int x = i, y = a / i;
      if (b % x == 0) {
        kou.push_back(x);
      }
      if (b % y == 0) {
        kou.push_back(y);
      }
    }
  }

  sort(all(kou));
  UNIQUE(kou);
  vl ans;
  rep(i, kou.size()) {
    ll x = kou[i];
    bool flag = true;
    for (int j = 0; j < ans.size(); j++) {
      if (gcd(x, ans[j]) > 1) {
        flag = false;
        break;
      }
    }
    if (flag) {
      ans.push_back(x);
    }
  }

  cout << ans.size() << endl;
}


Fixed submission:
#include <bits/stdc++.h>
#include <unistd.h>

using namespace std;
#define DEBUG(x) cerr << #x << ": " << x << endl;
#define DEBUG_VEC(v)                                                           \
  cerr << #v << ":";                                                           \
  for (int i = 0; i < v.size(); i++)                                           \
    cerr << " " << v[i];                                                       \
  cerr << endl
#define DEBUG_MAT(v)                                                           \
  cerr << #v << endl;                                                          \
  for (int i = 0; i < v.size(); i++) {                                         \
    for (int j = 0; j < v[i].size(); j++) {                                    \
      cerr << v[i][j] << " ";                                                  \
    }                                                                          \
    cerr << endl;                                                              \
  }
typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define vs vector<string>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
template <class S, class T>
pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first + t.first, s.second + t.second);
}
template <class S, class T>
pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) {
  return pair<S, T>(s.first - t.first, s.second - t.second);
}
template <class S, class T> ostream &operator<<(ostream &os, pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
#define X first
#define Y second
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
#define rrep1(i, n) for (int i = (n); i > 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(), c.end()
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const ll MOD = 1000000007;
// const ll MOD = 998244353;
const double pi = 3.14159265358979323846;
#define Sp(p) cout << setprecision(15) << fixed << p << endl;
int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
int dx2[8] = {1, 1, 0, -1, -1, -1, 0, 1}, dy2[8] = {0, 1, 1, 1, 0, -1, -1, -1};
#define fio()                                                                  \
  cin.tie(0);                                                                  \
  ios::sync_with_stdio(false);
// #define mp make_pair
// #define endl '\n'

ll gcd(ll a, ll b) {
  if (b > a) {
    swap(a, b);
  }
  ll r = a % b;
  while (r != 0) {
    a = b;
    b = r;
    r = a % b;
  }
  return b;
}

int main() {
  ll a, b;
  cin >> a >> b;

  vl kou;
  for (ll i = 1; i * i <= a; i++) {
    if (a % i == 0) {
      ll x = i, y = a / i;
      if (b % x == 0) {
        kou.push_back(x);
      }
      if (b % y == 0) {
        kou.push_back(y);
      }
    }
  }

  sort(all(kou));
  UNIQUE(kou);
  vl ans;
  rep(i, kou.size()) {
    ll x = kou[i];
    bool flag = true;
    for (int j = 0; j < ans.size(); j++) {
      if (gcd(x, ans[j]) > 1) {
        flag = false;
        break;
      }
    }
    if (flag) {
      ans.push_back(x);
    }
  }

  cout << ans.size() << endl;
}