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

#include <bits/stdc++.h>
using namespace std;

template <typename A, typename B> string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string &s) { return '"' + s + '"'; }

string to_string(const char *s) { return to_string((string)s); }

string to_string(bool b) { return (b ? "true" : "false"); }

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N> string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A> string to_string(A v) {
  if (v.size() >= 200) {
    return "Too big container";
  }

  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B> string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)

#define rep(i, n) for (int i = 0; i < n; ++i)
#define per(i, n) for (int i = n - 1; i >= 0; --i)
#define rep1(i, n) for (int i = 1; i <= n; ++i)
#define reps(i, s, n) for (int i = s; i < n; ++i)
#define all(c) begin(c), end(c)
template <typename T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PINT;
typedef pair<ll, ll> PLL;
const long long MOD = 1e9 + 7;
#define precout() cout << std::fixed << std::setprecision(20);
#define print(a) cout << a << endl;
const int INFI = (1 << 30) - 1;
const long long INFLL = (1LL << 62) - 1;
template <typename T> void printv(vector<T> &v) {
  int n = v.size() - 1;
  rep(i, n) cout << v[i] << " ";
  cout << v.back() << endl;
}
const int dy[4] = {0, 1, 0, -1};
const int dx[4] = {1, 0, -1, 0};
const int dy8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dx8[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
double deg2rad(double deg) { return deg * M_PI / 180; }
double rad2deg(double rad) { return rad * 180 / M_PI; }
void yesorno(bool flag) {
  if (flag)
    print("Yes") else print("No");
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int H, W;
  cin >> H >> W;
  int CH, CW, DH, DW;
  cin >> CH >> CW >> DH >> DW;
  --CH, --CW, --DH, --DW;
  vector<string> G(H);
  rep(i, H) { cin >> G[i]; }

  vector<vector<int>> warpCnt(H, vector<int>(W, -1));
  deque<PINT> q;
  q.push_front({DH, DW});
  warpCnt[DH][DW] = 0;

  while (!q.empty()) {
    PINT top = q.front();
    q.pop_front();
    int curH = top.first, curW = top.second;
    int curCnt = warpCnt[curH][curW];

    bool hasBlock = 0;
    rep(i, 4) {
      int nh = curH + dy[i], nw = curW + dx[i];
      if (nh >= 0 && nh < H && nw >= 0 && nw < W) {
        if (G[nh][nw] == '.') {
          if (warpCnt[nh][nw] == -1 || warpCnt[nh][nw] > curCnt) {
            warpCnt[nh][nw] = curCnt;
            q.push_front({nh, nw});
          }
        } else {
          hasBlock = 1;
        }
      }
    }

    if (!hasBlock)
      continue;

    reps(h, -2, 3) {
      reps(w, -2, 3) {
        if (h == 0 && w == 0)
          continue;

        int nh = curH + h, nw = curW + w;
        if (nh >= 0 && nh < H && nw >= 0 && nw < W && G[nh][nw] == '.') {
          if (warpCnt[nh][nw] == -1 || warpCnt[nh][nw] > curCnt + 1) {
            warpCnt[nh][nw] = curCnt + 1;

            q.push_back({nh, nw});
          }
        }
      }
    }
  }

  print(warpCnt[CH][CW]);
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

template <typename A, typename B> string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string &s) { return '"' + s + '"'; }

string to_string(const char *s) { return to_string((string)s); }

string to_string(bool b) { return (b ? "true" : "false"); }

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N> string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A> string to_string(A v) {
  if (v.size() >= 200) {
    return "Too big container";
  }

  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B> string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)

#define rep(i, n) for (int i = 0; i < n; ++i)
#define per(i, n) for (int i = n - 1; i >= 0; --i)
#define rep1(i, n) for (int i = 1; i <= n; ++i)
#define reps(i, s, n) for (int i = s; i < n; ++i)
#define all(c) begin(c), end(c)
template <typename T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PINT;
typedef pair<ll, ll> PLL;
const long long MOD = 1e9 + 7;
#define precout() cout << std::fixed << std::setprecision(20);
#define print(a) cout << a << endl;
const int INFI = (1 << 30) - 1;
const long long INFLL = (1LL << 62) - 1;
template <typename T> void printv(vector<T> &v) {
  int n = v.size() - 1;
  rep(i, n) cout << v[i] << " ";
  cout << v.back() << endl;
}
const int dy[4] = {0, 1, 0, -1};
const int dx[4] = {1, 0, -1, 0};
const int dy8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dx8[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
double deg2rad(double deg) { return deg * M_PI / 180; }
double rad2deg(double rad) { return rad * 180 / M_PI; }
void yesorno(bool flag) {
  if (flag)
    print("Yes") else print("No");
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int H, W;
  cin >> H >> W;
  int CH, CW, DH, DW;
  cin >> CH >> CW >> DH >> DW;
  --CH, --CW, --DH, --DW;
  vector<string> G(H);
  rep(i, H) { cin >> G[i]; }

  vector<vector<int>> warpCnt(H, vector<int>(W, -1));
  using Info = pair<int, PINT>;

  auto customCompare = [](Info &a, Info &b) { return a.first < b.first; };
  priority_queue<Info, vector<Info>, decltype(customCompare)> q(customCompare);
  q.push({0, {DH, DW}});
  warpCnt[DH][DW] = 0;

  while (!q.empty()) {
    Info top = q.top();
    q.pop();
    int curH = top.second.first, curW = top.second.second;
    int curCnt = top.first;

    if (warpCnt[curH][curW] < curCnt) {
      continue;
    }

    bool hasBlock = 0;
    rep(i, 4) {
      int nh = curH + dy[i], nw = curW + dx[i];
      if (nh >= 0 && nh < H && nw >= 0 && nw < W) {
        if (G[nh][nw] == '.') {
          if (warpCnt[nh][nw] == -1 || warpCnt[nh][nw] > curCnt) {
            warpCnt[nh][nw] = curCnt;
            q.push({curCnt, {nh, nw}});
          }
        } else {
          hasBlock = 1;
        }
      }
    }

    if (!hasBlock)
      continue;

    reps(h, -2, 3) {
      reps(w, -2, 3) {
        if (h == 0 && w == 0)
          continue;

        int nh = curH + h, nw = curW + w;
        if (nh >= 0 && nh < H && nw >= 0 && nw < W && G[nh][nw] == '.') {
          if (warpCnt[nh][nw] == -1 || warpCnt[nh][nw] > curCnt + 1) {
            warpCnt[nh][nw] = curCnt + 1;

            q.push({curCnt + 1, {nh, nw}});
          }
        }
      }
    }
  }

  print(warpCnt[CH][CW]);
}