Problem p02579 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define codefor                                                                \\
  int test;                                                                    \\
  scanf("%d", &test);                                                          \\
  while (test--)
#define INT(...)                                                               \\
  int __VA_ARGS__;                                                             \\
  in(__VA_ARGS__)
#define LL(...)                                                                \\
  ll __VA_ARGS__;                                                              \\
  in(__VA_ARGS__)
#define yn(ans)                                                                \\
  if (ans)                                                                     \\
    printf("Yes\\n");                                                           \\
  else                                                                         \\
    printf("No\\n")
#define YN(ans)                                                                \\
  if (ans)                                                                     \\
    printf("YES\\n");                                                           \\
  else                                                                         \\
    printf("NO\\n")
#define vector1d(type, name, ...) vector<type> name(__VA_ARGS__)
#define vector2d(type, name, h, ...)                                           \\
  vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
const int MOD = 1000000007;
// 入力系
void scan(int &a) { scanf("%d", &a); }
void scan(long long &a) { scanf("%lld", &a); }
template <class T> void scan(T &a) { cin >> a; }
template <class T> void scan(vector<T> &vec) {
  for (auto &&it : vec)
    scan(it);
}
void in() {}
template <class Head, class... Tail> void in(Head &head, Tail &...tail) {
  scan(head);
  in(tail...);
}
// 出力系
void print(const int &a) { printf("%d", a); }
void print(const long long &a) { printf("%lld", a); }
void print(const double &a) { printf("%.15lf", a); }
template <class T> void print(const T &a) { cout << a; }
template <class T> void print(const vector<T> &vec) {
  if (vec.empty())
    return;
  print(vec[0]);
  for (auto it = vec.begin(); ++it != vec.end();) {
    putchar(' ');
    print(*it);
  }
}
void out() { putchar('\\n'); }
template <class T> void out(const T &t) {
  print(t);
  putchar('\\n');
}
template <class Head, class... Tail>
void out(const Head &head, const Tail &...tail) {
  print(head);
  putchar(' ');
  out(tail...);
}
// デバッグ系
template <class T> void dprint(const T &a) { cerr << a; }
template <class T> void dprint(const vector<T> &vec) {
  if (vec.empty())
    return;
  cerr << vec[0];
  for (auto it = vec.begin(); ++it != vec.end();) {
    cerr << " " << *it;
  }
}
void debug() { cerr << endl; }
template <class T> void debug(const T &t) {
  dprint(t);
  cerr << endl;
}
template <class Head, class... Tail>
void debug(const Head &head, const Tail &...tail) {
  dprint(head);
  cerr << " ";
  debug(tail...);
}

int main() {
  int INF = 1000000000;
  pair<int, int> start, goal;
  INT(h, w, my, mx, gy, gx);
  my--;
  mx--;
  gy--;
  gx--;
  start = make_pair(my, mx);
  goal = make_pair(gy, gx);
  vector2d(char, maze, h, w);
  in(maze);
  queue<pair<int, int>> next, next2;
  next.push(start);
  vector<vector<int>> checked(h, vector<int>(w, INF));
  vector2d(bool, stock, h, w, false);
  int x, y;
  checked[start.first][start.second] = 0;
  stock[start.first][start.second] = true;
  do {
    while (!next.empty()) {
      y = next.front().first;
      x = next.front().second;
      next.pop();
      if (x - 1 >= 0 && checked[y][x] < checked[y][x - 1] &&
          maze[y][x - 1] != '#') {
        next.push(make_pair(y, x - 1));
        checked[y][x - 1] = checked[y][x];
        stock[y][x - 1] = true;
      }
      if (y - 1 >= 0 && checked[y][x] < checked[y - 1][x] &&
          maze[y - 1][x] != '#') {
        next.push(make_pair(y - 1, x));
        checked[y - 1][x] = checked[y][x];
        stock[y - 1][x] = true;
      }
      if (x + 1 < w && checked[y][x] < checked[y][x + 1] &&
          maze[y][x + 1] != '#') {
        next.push(make_pair(y, x + 1));
        checked[y][x + 1] = checked[y][x];
        stock[y][x + 1] = true;
      }
      if (y + 1 < h && checked[y][x] < checked[y + 1][x] &&
          maze[y + 1][x] != '#') {
        next.push(make_pair(y + 1, x));
        checked[y + 1][x] = checked[y][x];
        stock[y + 1][x] = true;
      }
      for (int dy = -2; dy <= 2; dy++) {
        for (int dx = -2; dx <= 2; dx++) {
          if (x + dx < 0 || y + dy < 0 || x + dx >= w || y + dy >= h)
            continue;
          else if (checked[y][x] + 1 < checked[y + dy][x + dx] &&
                   maze[y + dy][x + dx] != '#') {
            next2.push(make_pair(y + dy, x + dx));
            checked[y + dy][x + dx] = checked[y][x] + 1;
          }
        }
      }
    }
    while (!next2.empty()) {
      y = next2.front().first;
      x = next2.front().second;
      next2.pop();
      if (!stock[y][x])
        next.push(make_pair(y, x));
      stock[y][x] = true;
    }
  } while (!next.empty());
  if (checked[goal.first][goal.second] == INF)
    out(-1);
  else
    out(checked[goal.first][goal.second]);
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define codefor                                                                \\
  int test;                                                                    \\
  scanf("%d", &test);                                                          \\
  while (test--)
#define INT(...)                                                               \\
  int __VA_ARGS__;                                                             \\
  in(__VA_ARGS__)
#define LL(...)                                                                \\
  ll __VA_ARGS__;                                                              \\
  in(__VA_ARGS__)
#define yn(ans)                                                                \\
  if (ans)                                                                     \\
    printf("Yes\\n");                                                           \\
  else                                                                         \\
    printf("No\\n")
#define YN(ans)                                                                \\
  if (ans)                                                                     \\
    printf("YES\\n");                                                           \\
  else                                                                         \\
    printf("NO\\n")
#define vector1d(type, name, ...) vector<type> name(__VA_ARGS__)
#define vector2d(type, name, h, ...)                                           \\
  vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
const int MOD = 1000000007;
// 入力系
void scan(int &a) { scanf("%d", &a); }
void scan(long long &a) { scanf("%lld", &a); }
template <class T> void scan(T &a) { cin >> a; }
template <class T> void scan(vector<T> &vec) {
  for (auto &&it : vec)
    scan(it);
}
void in() {}
template <class Head, class... Tail> void in(Head &head, Tail &...tail) {
  scan(head);
  in(tail...);
}
// 出力系
void print(const int &a) { printf("%d", a); }
void print(const long long &a) { printf("%lld", a); }
void print(const double &a) { printf("%.15lf", a); }
template <class T> void print(const T &a) { cout << a; }
template <class T> void print(const vector<T> &vec) {
  if (vec.empty())
    return;
  print(vec[0]);
  for (auto it = vec.begin(); ++it != vec.end();) {
    putchar(' ');
    print(*it);
  }
}
void out() { putchar('\\n'); }
template <class T> void out(const T &t) {
  print(t);
  putchar('\\n');
}
template <class Head, class... Tail>
void out(const Head &head, const Tail &...tail) {
  print(head);
  putchar(' ');
  out(tail...);
}
// デバッグ系
template <class T> void dprint(const T &a) { cerr << a; }
template <class T> void dprint(const vector<T> &vec) {
  if (vec.empty())
    return;
  cerr << vec[0];
  for (auto it = vec.begin(); ++it != vec.end();) {
    cerr << " " << *it;
  }
}
void debug() { cerr << endl; }
template <class T> void debug(const T &t) {
  dprint(t);
  cerr << endl;
}
template <class Head, class... Tail>
void debug(const Head &head, const Tail &...tail) {
  dprint(head);
  cerr << " ";
  debug(tail...);
}

int main() {
  int INF = 1000000000;
  pair<int, int> start, goal;
  INT(h, w, my, mx, gy, gx);
  my--;
  mx--;
  gy--;
  gx--;
  start = make_pair(my, mx);
  goal = make_pair(gy, gx);
  vector2d(char, maze, h, w);
  in(maze);
  queue<pair<int, int>> next;
  next.push(start);
  vector<vector<int>> checked(h, vector<int>(w, INF));
  vector2d(bool, stock, h, w, false);
  int x, y;
  checked[start.first][start.second] = 0;
  stock[start.first][start.second] = true;
  while (!next.empty()) {
    y = next.front().first;
    x = next.front().second;
    next.pop();
    if (x - 1 >= 0 && checked[y][x] < checked[y][x - 1] &&
        maze[y][x - 1] != '#') {
      next.push(make_pair(y, x - 1));
      checked[y][x - 1] = checked[y][x];
      stock[y][x - 1] = true;
    }
    if (y - 1 >= 0 && checked[y][x] < checked[y - 1][x] &&
        maze[y - 1][x] != '#') {
      next.push(make_pair(y - 1, x));
      checked[y - 1][x] = checked[y][x];
      stock[y - 1][x] = true;
    }
    if (x + 1 < w && checked[y][x] < checked[y][x + 1] &&
        maze[y][x + 1] != '#') {
      next.push(make_pair(y, x + 1));
      checked[y][x + 1] = checked[y][x];
      stock[y][x + 1] = true;
    }
    if (y + 1 < h && checked[y][x] < checked[y + 1][x] &&
        maze[y + 1][x] != '#') {
      next.push(make_pair(y + 1, x));
      checked[y + 1][x] = checked[y][x];
      stock[y + 1][x] = true;
    }
    for (int dy = -2; dy <= 2; dy++) {
      for (int dx = -2; dx <= 2; dx++) {
        if (x + dx < 0 || y + dy < 0 || x + dx >= w || y + dy >= h)
          continue;
        else if (checked[y][x] + 1 < checked[y + dy][x + dx] &&
                 maze[y + dy][x + dx] != '#') {
          next.push(make_pair(y + dy, x + dx));
          checked[y + dy][x + dx] = checked[y][x] + 1;
          stock[y + dy][x + dx] = true;
        }
      }
    }
  }
  if (checked[goal.first][goal.second] == INF)
    out(-1);
  else
    out(checked[goal.first][goal.second]);
}