Problem p02644 (C++)

Buggy submission (status: Time Limit Exceeded):
#include "bits/stdc++.h"

#define _USE_MATH_DEFINES
#include <math.h>
using namespace std;

using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vvvll = std::vector<vvll>;
using ld = long double;
using vld = std::vector<ld>;
using vvld = std::vector<vld>;
using vvvld = std::vector<vvld>;
using bl = bool;
using vbl = std::vector<bl>;
using vvbl = std::vector<vbl>;
using vvvbl = std::vector<vvbl>;
using ss = string;
using vss = std::vector<ss>;

#define rep(i, n) for (ll(i) = 0; (i) < (ll)(n); (i)++)
#define repm(i, n, m) for (ll(i) = m; (i) < (ll)(n); (i)++)
#define repi(i, n) for (ll(i) = (n - 1); (i) >= (ll)(0); (i)--)
#define repit(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)

#define all(v) v.begin(), v.end()
#define println(v)                                                             \
  {                                                                            \
    ll i = 0;                                                                  \
    for (auto(a) : v) {                                                        \
      cerr << setw(2) << i << " : " << a << endl;                              \
      i++;                                                                     \
    }                                                                          \
  }
template <class T> void printsp(vector<T> v, size_t w = 3) {
  for (auto(a) : v) {
    cerr << setw(w) << a << " ";
  }
  cerr << endl;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> void bye(T a) {
  cout << a << '\n';
  exit(0);
}
template <class T1, class T2> void bye(T1 a, T2 b) {
  cout << a << " " << b << '\n';
  exit(0);
}
template <class T1, class T2, class T3> void bye(T1 a, T2 b, T3 c) {
  cout << a << " " << b << " " << c << '\n';
  exit(0);
}
template <class T> void bye(vector<T> A) {
  rep(i, (ll)A.size()) {
    cout << A[i];
    if (i != (ll)A.size() - 1) {
      cout << " ";
    }
  }
  cout << endl;
  exit(0);
}
// vector
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
// pair
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  os << "(" << pair_var.first << ", " << pair_var.second << ")";
  return os;
}
// vector<string>
ostream &operator<<(ostream &os, const vector<string> &vec) {

  ll N = to_string((ll)vec.size()).length();
  string head;
  rep(i, N + 2) { head += "-"; }
  rep(i, 40) { head += to_string(i % 10); }
  os << setw(N) << head << endl;

  for (ll i = 0; i < (ll)vec.size(); i++) {
    os << setw(N) << i << ": " << vec[i] << endl;
  }
  return os;
}
// vector<ll>
ostream &operator<<(ostream &os, const vector<ll> &vec) {
  ll N = to_string((ll)vec.size()).length();
  for (ll i = 0; i < (ll)vec.size(); i++) {
    os << setw(N) << i << ": " << vec[i] << endl;
  }
  return os;
}
// vector<ld>
ostream &operator<<(ostream &os, const vector<ld> &vec) {
  ll N = to_string((ll)vec.size()).length();
  for (ll i = 0; i < (ll)vec.size(); i++) {
    os << setw(N) << i << ": " << vec[i] << endl;
    // os <<vec[i] << endl;
  }
  return os;
}
// vvll
ostream &operator<<(ostream &os, const vector<vector<ll>> &mat) {
  ll keta = 1;
  rep(i, mat.size()) {
    rep(j, mat[i].size()) {
      ll x = mat[i][j];
      chmax(keta, (ll)to_string(x).length());
    }
  }
  ll N = to_string((ll)mat.size()).length();
  rep(i, mat.size()) {
    os << setw(N) << i << ": ";
    rep(j, mat[i].size()) {
      ll x = mat[i][j];
      os << setw(keta + 1) << x;
    }
    os << endl;
  }
  return os;
}

// vector
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {

  for (ll i = 0; i < (ll)vec.size(); i++) {
    // os << setw(3) <<i <<" : "<< setw(5) << vec[i] << endl;
    os << setw(5) << vec[i];
  }
  os << endl;
  return os;
}
// map
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  os << "{";
  repit(itr, map_var) {
    // for(auto itr :  map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      os << ", ";
    itr--;
  }
  os << "}";
  return os;
}
// set
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  os << "{";
  repit(itr, set_var) {
    // for( auto itr : set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      os << ", ";
    itr--;
  }
  os << "}";

  return os;
}
#define DUMPOUT cerr
#define DUMPCOLOR ("\033[36m")
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << DUMPCOLOR;
  DUMPOUT << head;
  if (sizeof...(Tail) > 0) {
    DUMPOUT << ", ";
  }
  dump_func(std::move(tail)...);
  DUMPOUT << "\033[m";
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \
  DUMPOUT << DUMPCOLOR << "" << string(#__VA_ARGS__) << ": "                   \
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \
          << "\033[m"                                                          \
          << "",                                                               \
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

struct Fast {
  Fast() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(std::numeric_limits<double>::max_digits10);
  }
} fast;

inline vll cinvll(ll N, ll minus = 0) {
  vll A(N);
  rep(i, N) {
    cin >> A[i];
    A[i] -= minus;
  }
  return move(A);
}
inline vvll zerosll(ll H, ll W, ll val = 0) {
  vvll A(H, vll(W, val));
  return move(A);
}
inline vvvll zerosll3(ll H, ll W, ll C, ll val = 0) {
  vvvll A(H, vvll(W, vll(C, val)));
  return move(A);
}

vvll cinvll2(ll H, ll W, ll bias = 0) {
  vvll A = zerosll(H, W);
  rep(i, H) {
    rep(j, W) {
      cin >> A[i][j];
      A[i][j] += bias;
    }
  }
  return move(A);
}
tuple<vll, vll> aho2(ll N) {
  vll A(N), B(N);
  rep(i, N) { cin >> A[i] >> B[i]; }
  return (make_tuple(A, B));
}

template <class T = ll> inline vector<T> cinv(ll N, T val = 0) {
  vector<T> v(N);
  rep(i, N) {
    cin >> v[i];
    v[i] += val;
  }
  return move(v);
}
template <class T = ll> inline vector<vector<T>> zeros(ll H, ll W, T val = 0) {
  vector<vector<T>> A(H, vector<T>(W, val));
  return move(A);
}
template <class T = ll>
inline vector<vector<vector<T>>> zeros3(ll H, ll W, ll C, T val = 0) {
  vector<vector<vector<T>>> A(H, vector<vector<T>>(W, vector<T>(C, val)));
  return move(A);
}

queue<vll> Q;
ll H, W, K;
ll sx, sy, ex, ey;
vss C;
vvll D;
void bfs_sub(ll dd, ll y, ll x, ll my, ll mx) {
  repm(k, K + 1, 1) {
    ll yy = y + k * my;
    ll xx = x + k * mx;
    // dump(yy,xx);
    if (yy < 0 or yy >= W or xx < 0 or xx >= H) {
      break;
    }
    if (C[xx][yy] == '@') {
      break;
    }
    if (D[xx][yy] != -1) {
      continue;
    }
    D[xx][yy] = dd;
    Q.push({dd, yy, xx});
  }
}
void bfs() {
  Q.push({0, sy, sx});
  D[sx][sy] = 0;
  while (not Q.empty()) {
    vll q = Q.front();
    Q.pop();
    ll d = q[0];
    ll y = q[1];
    ll x = q[2];
    // dump(d,y,x);
    /////////////////
    bfs_sub(d + 1, y, x, -1, 0);
    bfs_sub(d + 1, y, x, +1, 0);
    bfs_sub(d + 1, y, x, 0, -1);
    bfs_sub(d + 1, y, x, 0, +1);
  }
}

void func() {

  cin >> H >> W >> K;
  cin >> sx >> sy >> ex >> ey;
  sx--;
  sy--;
  ex--;
  ey--;
  C.resize(H);
  D = zeros(H, W, -1ll);
  rep(i, H) { cin >> C[i]; }
  dump(C);
  dump(D);
  dump(sx, sy, ex, ey);
  bfs();
  dump(D);
  cout << D[ex][ey] << endl;
}

int main() {
  dump("start");
  func();
  return 0;
}


Fixed submission:
#include "bits/stdc++.h"

#define _USE_MATH_DEFINES
#include <math.h>
using namespace std;

using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vvvll = std::vector<vvll>;
using ld = long double;
using vld = std::vector<ld>;
using vvld = std::vector<vld>;
using vvvld = std::vector<vvld>;
using bl = bool;
using vbl = std::vector<bl>;
using vvbl = std::vector<vbl>;
using vvvbl = std::vector<vvbl>;
using ss = string;
using vss = std::vector<ss>;

#define rep(i, n) for (ll(i) = 0; (i) < (ll)(n); (i)++)
#define repm(i, n, m) for (ll(i) = m; (i) < (ll)(n); (i)++)
#define repi(i, n) for (ll(i) = (n - 1); (i) >= (ll)(0); (i)--)
#define repit(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)

#define all(v) v.begin(), v.end()
#define println(v)                                                             \
  {                                                                            \
    ll i = 0;                                                                  \
    for (auto(a) : v) {                                                        \
      cerr << setw(2) << i << " : " << a << endl;                              \
      i++;                                                                     \
    }                                                                          \
  }
template <class T> void printsp(vector<T> v, size_t w = 3) {
  for (auto(a) : v) {
    cerr << setw(w) << a << " ";
  }
  cerr << endl;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> void bye(T a) {
  cout << a << '\n';
  exit(0);
}
template <class T1, class T2> void bye(T1 a, T2 b) {
  cout << a << " " << b << '\n';
  exit(0);
}
template <class T1, class T2, class T3> void bye(T1 a, T2 b, T3 c) {
  cout << a << " " << b << " " << c << '\n';
  exit(0);
}
template <class T> void bye(vector<T> A) {
  rep(i, (ll)A.size()) {
    cout << A[i];
    if (i != (ll)A.size() - 1) {
      cout << " ";
    }
  }
  cout << endl;
  exit(0);
}
// vector
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
// pair
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  os << "(" << pair_var.first << ", " << pair_var.second << ")";
  return os;
}
// vector<string>
ostream &operator<<(ostream &os, const vector<string> &vec) {

  ll N = to_string((ll)vec.size()).length();
  string head;
  rep(i, N + 2) { head += "-"; }
  rep(i, 40) { head += to_string(i % 10); }
  os << setw(N) << head << endl;

  for (ll i = 0; i < (ll)vec.size(); i++) {
    os << setw(N) << i << ": " << vec[i] << endl;
  }
  return os;
}
// vector<ll>
ostream &operator<<(ostream &os, const vector<ll> &vec) {
  ll N = to_string((ll)vec.size()).length();
  for (ll i = 0; i < (ll)vec.size(); i++) {
    os << setw(N) << i << ": " << vec[i] << endl;
  }
  return os;
}
// vector<ld>
ostream &operator<<(ostream &os, const vector<ld> &vec) {
  ll N = to_string((ll)vec.size()).length();
  for (ll i = 0; i < (ll)vec.size(); i++) {
    os << setw(N) << i << ": " << vec[i] << endl;
    // os <<vec[i] << endl;
  }
  return os;
}
// vvll
ostream &operator<<(ostream &os, const vector<vector<ll>> &mat) {
  ll keta = 1;
  rep(i, mat.size()) {
    rep(j, mat[i].size()) {
      ll x = mat[i][j];
      chmax(keta, (ll)to_string(x).length());
    }
  }
  ll N = to_string((ll)mat.size()).length();
  rep(i, mat.size()) {
    os << setw(N) << i << ": ";
    rep(j, mat[i].size()) {
      ll x = mat[i][j];
      os << setw(keta + 1) << x;
    }
    os << endl;
  }
  return os;
}

// vector
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {

  for (ll i = 0; i < (ll)vec.size(); i++) {
    // os << setw(3) <<i <<" : "<< setw(5) << vec[i] << endl;
    os << setw(5) << vec[i];
  }
  os << endl;
  return os;
}
// map
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  os << "{";
  repit(itr, map_var) {
    // for(auto itr :  map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      os << ", ";
    itr--;
  }
  os << "}";
  return os;
}
// set
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  os << "{";
  repit(itr, set_var) {
    // for( auto itr : set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      os << ", ";
    itr--;
  }
  os << "}";

  return os;
}
#define DUMPOUT cerr
#define DUMPCOLOR ("\033[36m")
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << DUMPCOLOR;
  DUMPOUT << head;
  if (sizeof...(Tail) > 0) {
    DUMPOUT << ", ";
  }
  dump_func(std::move(tail)...);
  DUMPOUT << "\033[m";
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \
  DUMPOUT << DUMPCOLOR << "" << string(#__VA_ARGS__) << ": "                   \
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \
          << "\033[m"                                                          \
          << "",                                                               \
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

struct Fast {
  Fast() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(std::numeric_limits<double>::max_digits10);
  }
} fast;

inline vll cinvll(ll N, ll minus = 0) {
  vll A(N);
  rep(i, N) {
    cin >> A[i];
    A[i] -= minus;
  }
  return move(A);
}
inline vvll zerosll(ll H, ll W, ll val = 0) {
  vvll A(H, vll(W, val));
  return move(A);
}
inline vvvll zerosll3(ll H, ll W, ll C, ll val = 0) {
  vvvll A(H, vvll(W, vll(C, val)));
  return move(A);
}

vvll cinvll2(ll H, ll W, ll bias = 0) {
  vvll A = zerosll(H, W);
  rep(i, H) {
    rep(j, W) {
      cin >> A[i][j];
      A[i][j] += bias;
    }
  }
  return move(A);
}
tuple<vll, vll> aho2(ll N) {
  vll A(N), B(N);
  rep(i, N) { cin >> A[i] >> B[i]; }
  return (make_tuple(A, B));
}

template <class T = ll> inline vector<T> cinv(ll N, T val = 0) {
  vector<T> v(N);
  rep(i, N) {
    cin >> v[i];
    v[i] += val;
  }
  return move(v);
}
template <class T = ll> inline vector<vector<T>> zeros(ll H, ll W, T val = 0) {
  vector<vector<T>> A(H, vector<T>(W, val));
  return move(A);
}
template <class T = ll>
inline vector<vector<vector<T>>> zeros3(ll H, ll W, ll C, T val = 0) {
  vector<vector<vector<T>>> A(H, vector<vector<T>>(W, vector<T>(C, val)));
  return move(A);
}

queue<vll> Q;
ll H, W, K;
ll sx, sy, ex, ey;
vss C;
vvll D;
void bfs_sub(ll dd, ll y, ll x, ll my, ll mx) {
  repm(k, K + 1, 1) {
    ll yy = y + k * my;
    ll xx = x + k * mx;
    // dump(yy,xx);
    if (yy < 0 or yy >= W or xx < 0 or xx >= H) {
      break;
    }
    if (D[xx][yy] == D[x][y])
      break;
    if (C[xx][yy] == '@') {
      break;
    }
    if (D[xx][yy] != -1) {
      continue;
    }
    D[xx][yy] = dd;
    Q.push({dd, yy, xx});
  }
}
void bfs() {
  Q.push({0, sy, sx});
  D[sx][sy] = 0;
  while (not Q.empty()) {
    vll q = Q.front();
    Q.pop();
    ll d = q[0];
    ll y = q[1];
    ll x = q[2];
    // dump(d,y,x);
    /////////////////
    bfs_sub(d + 1, y, x, -1, 0);
    bfs_sub(d + 1, y, x, +1, 0);
    bfs_sub(d + 1, y, x, 0, -1);
    bfs_sub(d + 1, y, x, 0, +1);
  }
}

void func() {

  cin >> H >> W >> K;
  cin >> sx >> sy >> ex >> ey;
  sx--;
  sy--;
  ex--;
  ey--;
  C.resize(H);
  D = zeros(H, W, -1ll);
  rep(i, H) { cin >> C[i]; }
  dump(C);
  dump(D);
  dump(sx, sy, ex, ey);
  bfs();
  dump(D);
  cout << D[ex][ey] << endl;
}

int main() {
  dump("start");
  func();
  return 0;
}