Problem p02579 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
template <class T> using PQ = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i, a, n) for (int i = (a); i < (n); ++i)
#define eFOR(i, a, n) for (int i = (a); i <= (n); ++i)
#define rFOR(i, a, n) for (int i = (n)-1; i >= (a); --i)
#define erFOR(i, a, n) for (int i = (n); i >= (a); --i)
#define each(i, a) for (auto &i : a)
#define SORT(a) sort(a.begin(), a.end())
#define rSORT(a) sort(a.rbegin(), a.rend())
#define fSORT(a, f) sort(a.begin(), a.end(), f)
#define all(a) a.begin(), a.end()
#define out(y, x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x))
#define tp(a, i) get<i>(a)
#define line cout << "-----------------------------\n"
#define ENDL(i, n) ((i) == (n)-1 ? "\n" : " ")
#define stop system("pause")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
constexpr ld eps = 1e-10;
constexpr ld pi = 3.1415926535897932;
template <class T> inline bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
inline void init() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
}
template <class T> inline istream &operator>>(istream &is, vector<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <class T> inline istream &operator>>(istream &is, deque<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <class T, class U>
inline istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}
template <class T> inline vector<T> vec(size_t a) { return vector<T>(a); }
template <class T> inline vector<T> defvec(T def, size_t a) {
  return vector<T>(a, def);
}
template <class T, class... Ts> inline auto vec(size_t a, Ts... ts) {
  return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...));
}
template <class T, class... Ts> inline auto defvec(T def, size_t a, Ts... ts) {
  return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...));
}
template <class T> inline void print(const T &a) { cout << a << "\n"; }
template <class T, class... Ts> inline void print(const T &a, const Ts &...ts) {
  cout << a << " ";
  print(ts...);
}
template <class T> inline void print(const vector<T> &v) {
  for (int i = 0; i < v.size(); ++i)
    cout << v[i] << (i == v.size() - 1 ? "\n" : " ");
}
template <class T> inline void print(const vector<vector<T>> &v) {
  for (auto &a : v)
    print(a);
}
inline string reversed(const string &s) {
  string t = s;
  reverse(all(t));
  return t;
}

int main() {
  init();

  int h, w;
  cin >> h >> w;
  int sy, sx, gy, gx;
  cin >> sy >> sx >> gy >> gx;
  --sy, --sx, --gy, --gx;
  VS s(h);
  cin >> s;
  auto dp = defvec<int>(INF, h, w);
  dp[sy][sx] = 0;
  deque<pair<int, int>> bfs;
  bfs.emplace_back(sy, sx);
  while (!bfs.empty()) {
    auto [y, x] = bfs.front();
    bfs.pop_front();
    eFOR(ny, max(0, y - 2), min(h - 1, y + 2))
        eFOR(nx, max(0, x - 2), min(w - 1, x + 2)) {
      if (s[ny][nx] == '.' &&
          chmin(dp[ny][nx],
                dp[y][x] + (abs(y - ny) + abs(x - nx) == 1 ? 0 : 1))) {
        bfs.emplace_back(ny, nx);
      }
    }
  }

  print(dp[gy][gx] == INF ? -1 : dp[gy][gx]);

  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
template <class T> using PQ = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i, a, n) for (int i = (a); i < (n); ++i)
#define eFOR(i, a, n) for (int i = (a); i <= (n); ++i)
#define rFOR(i, a, n) for (int i = (n)-1; i >= (a); --i)
#define erFOR(i, a, n) for (int i = (n); i >= (a); --i)
#define each(i, a) for (auto &i : a)
#define SORT(a) sort(a.begin(), a.end())
#define rSORT(a) sort(a.rbegin(), a.rend())
#define fSORT(a, f) sort(a.begin(), a.end(), f)
#define all(a) a.begin(), a.end()
#define out(y, x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x))
#define tp(a, i) get<i>(a)
#define line cout << "-----------------------------\n"
#define ENDL(i, n) ((i) == (n)-1 ? "\n" : " ")
#define stop system("pause")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
constexpr ld eps = 1e-10;
constexpr ld pi = 3.1415926535897932;
template <class T> inline bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
inline void init() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
}
template <class T> inline istream &operator>>(istream &is, vector<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <class T> inline istream &operator>>(istream &is, deque<T> &v) {
  for (auto &a : v)
    is >> a;
  return is;
}
template <class T, class U>
inline istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}
template <class T> inline vector<T> vec(size_t a) { return vector<T>(a); }
template <class T> inline vector<T> defvec(T def, size_t a) {
  return vector<T>(a, def);
}
template <class T, class... Ts> inline auto vec(size_t a, Ts... ts) {
  return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...));
}
template <class T, class... Ts> inline auto defvec(T def, size_t a, Ts... ts) {
  return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...));
}
template <class T> inline void print(const T &a) { cout << a << "\n"; }
template <class T, class... Ts> inline void print(const T &a, const Ts &...ts) {
  cout << a << " ";
  print(ts...);
}
template <class T> inline void print(const vector<T> &v) {
  for (int i = 0; i < v.size(); ++i)
    cout << v[i] << (i == v.size() - 1 ? "\n" : " ");
}
template <class T> inline void print(const vector<vector<T>> &v) {
  for (auto &a : v)
    print(a);
}
inline string reversed(const string &s) {
  string t = s;
  reverse(all(t));
  return t;
}

int main() {
  init();

  int h, w;
  cin >> h >> w;
  int sy, sx, gy, gx;
  cin >> sy >> sx >> gy >> gx;
  --sy, --sx, --gy, --gx;
  VS s(h);
  cin >> s;
  auto dp = defvec<int>(INF, h, w);
  dp[sy][sx] = 0;
  deque<pair<int, int>> bfs;
  bfs.emplace_back(sy, sx);
  while (!bfs.empty()) {
    auto [y, x] = bfs.front();
    bfs.pop_front();
    eFOR(ny, max(0, y - 2), min(h - 1, y + 2))
        eFOR(nx, max(0, x - 2), min(w - 1, x + 2)) {
      if (s[ny][nx] == '#')
        continue;
      int cost = (abs(y - ny) + abs(x - nx) == 1 ? 0 : 1);
      if (cost == 1) {
        if (chmin(dp[ny][nx], dp[y][x] + 1)) {
          bfs.emplace_back(ny, nx);
        }
      } else {
        if (chmin(dp[ny][nx], dp[y][x])) {
          bfs.emplace_front(ny, nx);
        }
      }
    }
  }

  print(dp[gy][gx] == INF ? -1 : dp[gy][gx]);

  return 0;
}