Problem p02680 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits.h>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <time.h>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
using ll = long long;
#define rep(i, a, b) for (int i = a; i < b; i++)
#define rrep(i, a, b) for (int i = b - 1; i >= a; i--)
#define ALL(a) a.begin(), a.end()
using pii = pair<int, int>;
using piii = pair<pii, int>;
using pll = pair<long long, long long>;
using plll = pair<pll, long long>;
// #pragma GCC optimize("Ofast")
#define pcnt __builtin_popcount
#define buli(x) __builtin_popcountll(x)
#define pb push_back
#define mp make_pair
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define isSquare(x) (sqrt(x) * sqrt(x) == x)
template <class T> inline bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
};
template <class T> inline bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
};
inline void in(void) { return; }
template <typename First, typename... Rest>
void in(First &first, Rest &...rest) {
  cin >> first;
  in(rest...);
  return;
}
inline void out(void) {
  cout << "\n";
  return;
}
template <typename First, typename... Rest>
void out(First first, Rest... rest) {
  cout << first << " ";
  out(rest...);
  return;
}
const double EPS = 1e-9;
const int mod = 1e9 + 7;
const int INF = 1e9;
const long long INFLL = 1e18;
void iosetup() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v)
    is >> in;
  return is;
}
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>
pair<S, T> operator*(const pair<S, T> &s, const S &t) {
  return pair<S, T>(s.first * t, s.second * t);
}
template <typename T> void Exit(T first) {
  cout << first << endl;
  exit(0);
};
template <int mod> struct ModInt {
  unsigned x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  ModInt &operator+=(const ModInt &p) {
    if ((x += p.x) >= mod)
      x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if ((x += mod - p.x) >= mod)
      x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt operator-() const { return ModInt(-x); }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }
  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }
  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while (n > 0) {
      if (n & 1)
        ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }
  friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; }
  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt<mod>(t);
    return (is);
  }
  static int get_mod() { return mod; }
};
using modint = ModInt<mod>;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const pii dxy[4] = {pii(1, 0), pii(0, 1), pii(-1, 0), pii(0, -1)};
const int calender[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int ucalender[13] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
bool range(int a, int b, int x) {
  if (a <= x and x < b)
    return true;
  else
    return false;
}
bool range(int a, int b, int c, int d, pii p) {
  if (a <= p.first and p.first < b and c <= p.second and p.second < d)
    return true;
  else
    return false;
}

unordered_map<int, int> Z(vector<int> v) {
  unordered_map<int, int> ret;
  for (auto x : v) {
    int n = ret.size();
    ret[x] = n;
  }
  return ret;
}

struct GridUnionFind {
  int H, W;
  std::vector<int> par, cou;
  using P = std::pair<int, int>;
  GridUnionFind(int H_, int W_) : H(H_), W(W_), par(H * W), cou(H * W, 1) {
    std::iota(par.begin(), par.end(), 0);
  }
  inline int id_(int h, int w) { return h * W + w; }
  inline bool coordinate_valid(int h, int w) {
    return h >= 0 and h < H and w >= 0 and w < W;
  }
  int _find(int x) { return (par[x] == x) ? x : (par[x] = _find(par[x])); }
  bool _unite(int x, int y) {
    x = _find(x), y = _find(y);
    if (x == y)
      return false;
    if (cou[x] < cou[y])
      std::swap(x, y);
    par[y] = x, cou[x] += cou[y];
    return true;
  }
  int find(int h, int w) {
    assert(coordinate_valid(h, w));
    return _find(id_(h, w));
  }
  bool unite(int h, int w, int h2, int w2) {
    assert(coordinate_valid(h, w) and coordinate_valid(h2, w2));
    return _unite(id_(h, w), id_(h2, w2));
  }
  int count(int h, int w) { return cou[find(h, w)]; }
  bool same(int h, int w, int h2, int w2) { return find(h, w) == find(h2, w2); }

  int find(P p) { return find(p.first, p.second); }
  bool unite(P p, P p2) {
    return unite(p.first, p.second, p2.first, p2.second);
  }
  int count(P p) { return count(p.first, p.second); }
  bool same(P p, P p2) { return same(p.first, p.second, p2.first, p2.second); }

  void merge_outer() {
    for (int h = 0; h < H - 1; h++)
      unite(h, 0, h + 1, 0), unite(h, W - 1, h + 1, W - 1);
    for (int w = 0; w < W - 1; w++)
      unite(0, w, 0, w + 1), unite(H - 1, w, H - 1, w + 1);
  }
  friend std::ostream &operator<<(std::ostream &os, GridUnionFind &g) {
    constexpr int WW = 3;
    os << "[(" << g.H << " * " << g.W << " grid)\n";
    for (int i = 0; i < g.H; i++) {
      for (int j = 0; j < g.W - 1; j++) {
        os << std::setw(WW) << g.find(i, j)
           << (g.same(i, j, i, j + 1) ? '-' : ' ');
      }
      os << std::setw(WW) << g.find(i, g.W - 1) << '\n';
      if (i < g.H - 1) {
        for (int j = 0; j < g.W; j++)
          os << std::setw(WW + 1) << (g.same(i, j, i + 1, j) ? "| " : "  ");
        os << "\n";
      }
    }
    os << "]\n";
    return os;
  }
};

// https://atcoder.jp/contests/abc168/submissions/13313031
int main() {
  iosetup();
  int n, m;
  cin >> n >> m;
  vector<int> zx{-INF, 0, INF}, zy{-INF, 0, INF};
  // cerr << zx << endl;
  vector<int> A(n), B(n), C(n), D(m), E(m), F(m);
  rep(i, 0, n) cin >> A[i] >> B[i] >> C[i];
  rep(i, 0, m) cin >> D[i] >> E[i] >> F[i];

  zx.insert(zx.end(), ALL(A));
  zx.insert(zx.end(), ALL(B));
  zx.insert(zx.end(), ALL(D));

  zy.insert(zy.end(), ALL(C));
  zy.insert(zy.end(), ALL(E));
  zy.insert(zy.end(), ALL(F));

  sort(ALL(zx));
  UNIQUE(zx);
  sort(ALL(zy));
  UNIQUE(zy);
  unordered_map<int, int> xinv = Z(zx), yinv = Z(zy);

  vector<vector<int>> conn1(zx.size(), vector<int>(zy.size(), 0));
  vector<vector<int>> conn2(zx.size(), vector<int>(zy.size(), 0));
  rep(i, 0, n) {
    int x1 = xinv[A[i]], x2 = xinv[B[i]], y = yinv[C[i]];
    conn1[x1][y - 1]++;
    conn1[x2][y - 1]--;
  }
  rep(i, 0, conn1.size() - 1) rep(j, 0, conn1[i].size()) conn1[i + 1][j] +=
      conn1[i][j];

  rep(j, 0, m) {
    int x = xinv[D[j]], y1 = yinv[E[j]], y2 = yinv[F[j]];
    conn2[x - 1][y1]++;
    conn2[x - 1][y2]--;
  }
  rep(i, 0, conn2.size()) rep(j, 0, conn2[i].size() - 1) conn2[i][j + 1] +=
      conn2[i][j];

  GridUnionFind uf(zx.size(), zy.size());
  rep(x, 0, zx.size()) rep(y, 0, zy.size()) {
    if (x + 1 < zx.size() and conn2[x][y] == 0)
      uf.unite(x, y, x + 1, y);
    if (y + 1 < zy.size() and conn1[x][y] == 0)
      uf.unite(x, y, x, y + 1);
  }

  int xz = xinv[0], yz = yinv[0];

  if (uf.same(xz, yz, 0, 0))
    Exit("INF");
  ll ans = 0;
  rep(x, 0, zx.size() - 1) rep(y, 0, zy.size() - 1) if (uf.same(x, y, xz, yz)) {
    ans += (ll)(zx[x + 1] - zx[x]) * (zy[y + 1] - zy[y]);
  }
  cout << ans << endl;

  return 0;
}

Fixed submission:
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits.h>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <time.h>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
using ll = long long;
#define rep(i, a, b) for (int i = a; i < b; i++)
#define rrep(i, a, b) for (int i = b - 1; i >= a; i--)
#define ALL(a) a.begin(), a.end()
using pii = pair<int, int>;
using piii = pair<pii, int>;
using pll = pair<long long, long long>;
using plll = pair<pll, long long>;
// #pragma GCC optimize("Ofast")
#define pcnt __builtin_popcount
#define buli(x) __builtin_popcountll(x)
#define pb push_back
#define mp make_pair
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define isSquare(x) (sqrt(x) * sqrt(x) == x)
template <class T> inline bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
};
template <class T> inline bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
};
inline void in(void) { return; }
template <typename First, typename... Rest>
void in(First &first, Rest &...rest) {
  cin >> first;
  in(rest...);
  return;
}
inline void out(void) {
  cout << "\n";
  return;
}
template <typename First, typename... Rest>
void out(First first, Rest... rest) {
  cout << first << " ";
  out(rest...);
  return;
}
const double EPS = 1e-9;
const int mod = 1e9 + 7;
const int INF = 1e9 + 100;
const long long INFLL = 1e18;
void iosetup() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v)
    is >> in;
  return is;
}
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>
pair<S, T> operator*(const pair<S, T> &s, const S &t) {
  return pair<S, T>(s.first * t, s.second * t);
}
template <typename T> void Exit(T first) {
  cout << first << endl;
  exit(0);
};
template <int mod> struct ModInt {
  unsigned x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  ModInt &operator+=(const ModInt &p) {
    if ((x += p.x) >= mod)
      x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if ((x += mod - p.x) >= mod)
      x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt operator-() const { return ModInt(-x); }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }
  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }
  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while (n > 0) {
      if (n & 1)
        ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }
  friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; }
  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt<mod>(t);
    return (is);
  }
  static int get_mod() { return mod; }
};
using modint = ModInt<mod>;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const pii dxy[4] = {pii(1, 0), pii(0, 1), pii(-1, 0), pii(0, -1)};
const int calender[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int ucalender[13] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
bool range(int a, int b, int x) {
  if (a <= x and x < b)
    return true;
  else
    return false;
}
bool range(int a, int b, int c, int d, pii p) {
  if (a <= p.first and p.first < b and c <= p.second and p.second < d)
    return true;
  else
    return false;
}

unordered_map<int, int> Z(vector<int> v) {
  unordered_map<int, int> ret;
  for (auto x : v) {
    int n = ret.size();
    ret[x] = n;
  }
  return ret;
}

struct GridUnionFind {
  int H, W;
  std::vector<int> par, cou;
  using P = std::pair<int, int>;
  GridUnionFind(int H_, int W_) : H(H_), W(W_), par(H * W), cou(H * W, 1) {
    std::iota(par.begin(), par.end(), 0);
  }
  inline int id_(int h, int w) { return h * W + w; }
  inline bool coordinate_valid(int h, int w) {
    return h >= 0 and h < H and w >= 0 and w < W;
  }
  int _find(int x) { return (par[x] == x) ? x : (par[x] = _find(par[x])); }
  bool _unite(int x, int y) {
    x = _find(x), y = _find(y);
    if (x == y)
      return false;
    if (cou[x] < cou[y])
      std::swap(x, y);
    par[y] = x, cou[x] += cou[y];
    return true;
  }
  int find(int h, int w) {
    assert(coordinate_valid(h, w));
    return _find(id_(h, w));
  }
  bool unite(int h, int w, int h2, int w2) {
    assert(coordinate_valid(h, w) and coordinate_valid(h2, w2));
    return _unite(id_(h, w), id_(h2, w2));
  }
  int count(int h, int w) { return cou[find(h, w)]; }
  bool same(int h, int w, int h2, int w2) { return find(h, w) == find(h2, w2); }

  int find(P p) { return find(p.first, p.second); }
  bool unite(P p, P p2) {
    return unite(p.first, p.second, p2.first, p2.second);
  }
  int count(P p) { return count(p.first, p.second); }
  bool same(P p, P p2) { return same(p.first, p.second, p2.first, p2.second); }

  void merge_outer() {
    for (int h = 0; h < H - 1; h++)
      unite(h, 0, h + 1, 0), unite(h, W - 1, h + 1, W - 1);
    for (int w = 0; w < W - 1; w++)
      unite(0, w, 0, w + 1), unite(H - 1, w, H - 1, w + 1);
  }
  friend std::ostream &operator<<(std::ostream &os, GridUnionFind &g) {
    constexpr int WW = 3;
    os << "[(" << g.H << " * " << g.W << " grid)\n";
    for (int i = 0; i < g.H; i++) {
      for (int j = 0; j < g.W - 1; j++) {
        os << std::setw(WW) << g.find(i, j)
           << (g.same(i, j, i, j + 1) ? '-' : ' ');
      }
      os << std::setw(WW) << g.find(i, g.W - 1) << '\n';
      if (i < g.H - 1) {
        for (int j = 0; j < g.W; j++)
          os << std::setw(WW + 1) << (g.same(i, j, i + 1, j) ? "| " : "  ");
        os << "\n";
      }
    }
    os << "]\n";
    return os;
  }
};

// https://atcoder.jp/contests/abc168/submissions/13313031
int main() {
  iosetup();
  int n, m;
  cin >> n >> m;
  vector<int> zx{-INF, 0, INF}, zy{-INF, 0, INF};
  // cerr << zx << endl;
  vector<int> A(n), B(n), C(n), D(m), E(m), F(m);
  rep(i, 0, n) cin >> A[i] >> B[i] >> C[i];
  rep(i, 0, m) cin >> D[i] >> E[i] >> F[i];

  zx.insert(zx.end(), ALL(A));
  zx.insert(zx.end(), ALL(B));
  zx.insert(zx.end(), ALL(D));

  zy.insert(zy.end(), ALL(C));
  zy.insert(zy.end(), ALL(E));
  zy.insert(zy.end(), ALL(F));

  sort(ALL(zx));
  UNIQUE(zx);
  sort(ALL(zy));
  UNIQUE(zy);
  unordered_map<int, int> xinv = Z(zx), yinv = Z(zy);

  vector<vector<int>> conn1(zx.size(), vector<int>(zy.size(), 0));
  vector<vector<int>> conn2(zx.size(), vector<int>(zy.size(), 0));
  rep(i, 0, n) {
    int x1 = xinv[A[i]], x2 = xinv[B[i]], y = yinv[C[i]];
    conn1[x1][y - 1]++;
    conn1[x2][y - 1]--;
  }
  rep(i, 0, conn1.size() - 1) rep(j, 0, conn1[i].size()) conn1[i + 1][j] +=
      conn1[i][j];

  rep(j, 0, m) {
    int x = xinv[D[j]], y1 = yinv[E[j]], y2 = yinv[F[j]];
    conn2[x - 1][y1]++;
    conn2[x - 1][y2]--;
  }
  rep(i, 0, conn2.size()) rep(j, 0, conn2[i].size() - 1) conn2[i][j + 1] +=
      conn2[i][j];

  GridUnionFind uf(zx.size(), zy.size());
  rep(x, 0, zx.size()) rep(y, 0, zy.size()) {
    if (x + 1 < zx.size() and conn2[x][y] == 0)
      uf.unite(x, y, x + 1, y);
    if (y + 1 < zy.size() and conn1[x][y] == 0)
      uf.unite(x, y, x, y + 1);
  }

  int xz = xinv[0], yz = yinv[0];

  if (uf.same(xz, yz, 0, 0))
    Exit("INF");
  ll ans = 0;
  rep(x, 0, zx.size() - 1) rep(y, 0, zy.size() - 1) if (uf.same(x, y, xz, yz)) {
    ans += (ll)(zx[x + 1] - zx[x]) * (zy[y + 1] - zy[y]);
  }
  cout << ans << endl;

  return 0;
}