Problem p02644 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
using Real = long double;
using Point = complex<Real>; // Point and Vector2d is the same!
using Vector2d = complex<Real>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
const double EPS = 1e-15;
const double PI = 3.14159265358979323846;
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
istream &operator>>(istream &is, Point &p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \\
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \\
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \\
          << "    ",                                                           \\
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif
int h, w;
long double k;
int f(int i, int j) { return i * w + j; }
P d4[4] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> h >> w >> k;
  int sx, sy, gx, gy;
  cin >> sy >> sx >> gy >> gx;
  sx--, sy--, gx--, gy--;
  vector<vector<char>> grid(h, vector<char>(w));
  cin >> grid;
  vector<vector<vector<long double>>> d(
      h, vector<vector<long double>>(w, vector<long double>(4, 2000001)));
  d[sy][sx][0] = d[sy][sx][1] = d[sy][sx][2] = d[sy][sx][3] = 0;

  priority_queue<tuple<long double, int, int, int>,
                 vector<tuple<long double, int, int, int>>,
                 greater<tuple<long double, int, int, int>>>
      pq;
  pq.push({0, sy, sx, 0}), pq.push({0, sy, sx, 1}), pq.push({0, sy, sx, 2}),
      pq.push({0, sy, sx, 3});
  while (!pq.empty()) {
    auto tmp = pq.top();
    pq.pop();
    long double cost = get<0>(tmp);
    int y = get<1>(tmp), x = get<2>(tmp), dir = get<3>(tmp);
    if (d[y][x][dir] < cost)
      continue;
    for (int i = 0; i < 4; i++) {
      int ny = d4[i].F + y, nx = d4[i].S + x;
      if (ny >= 0 && ny < h && nx >= 0 && nx < w) {
        if (grid[ny][nx] == '@')
          continue;
        if (i == dir) {
          if (chmin(d[ny][nx][i], cost + 1.0 / k))
            pq.push({d[ny][nx][i], ny, nx, i});
        } else if (chmin(d[ny][nx][i], ceil(cost) + 1.0 / k))
          pq.push({d[ny][nx][i], ny, nx, i});
        // dump(ny, nx, i, d[ny][nx][i]);
      }
    }
  }
  int ans = min({ceil(d[gy][gx][0]), ceil(d[gy][gx][1]), ceil(d[gy][gx][2]),
                 ceil(d[gy][gx][3])});
  if (ans == 2000001)
    print(-1);
  else
    print(ans);
}


Error: WA

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
using Real = long double;
using Point = complex<Real>; // Point and Vector2d is the same!
using Vector2d = complex<Real>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
const double EPS = 1e-15;
const double PI = 3.14159265358979323846;
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
istream &operator>>(istream &is, Point &p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \\
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \\
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \\
          << "    ",                                                           \\
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

vector<int> dijkstra(WeightedGraph &G, int s = 0) {
  vector<int> d(G.size(), INF);
  priority_queue<P, vector<P>, greater<P>> que;
  d[s] = 0;
  que.push(P(0, s));
  while (!que.empty()) {
    P p = que.top();
    que.pop();
    int v = p.second;
    if (v == s) {
      if (d[v] < p.first)
        continue;
      int sz = G[v].size();
      rep(i, sz) if (chmin(d[G[v][i].F], d[v] + G[v][i].S + 1))
          que.push(P(d[G[v][i].F] + 1, G[v][i].F));
    } else {
      if (d[v] < p.first)
        continue;
      int sz = G[v].size();
      rep(i, sz) if (chmin(d[G[v][i].F], d[v] + G[v][i].S))
          que.push(P(d[G[v][i].F], G[v][i].F));
    }
  }
  return d;
}
signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int h, w, k;
  cin >> h >> w >> k;
  int num = h * w;
  int sx, sy, gx, gy;
  cin >> sx >> sy >> gx >> gy;
  vector<vector<char>> grid(h, vector<char>(w));
  cin >> grid;
  WeightedGraph g(4 * h * w);
  // 0 + i*w + j -> 右に行きたい
  dump(grid);
  rep(i, h) {
    set<int> se;
    rep(j, w) {
      g[i * w + j].pb({i * w + j + num, 1});
      g[num + i * w + j].pb({i * w + j + 2 * num, 1});
      g[2 * num + i * w + j].pb({i * w + j + 3 * num, 1});
      g[3 * num + i * w + j].pb({i * w + j, 1});
      if (grid[i][j] == '@') {
        se.insert(j);
        continue;
      }
      if (j != 0) {
        if (grid[i][j - 1] == '.')
          g[i * w + j].pb({i * w + j - 1, 0});
      }
    }
    se.insert(INF);
    se.insert(-1);
    rep(j, w) {
      if (grid[i][j] == '@')
        continue;
      if (*se.upper_bound(j) != INF) {
        g[i * w + j].pb({i * w + (*se.upper_bound(j)) - 1, 1});
      }
    }
    rrep(j, w) { // 左に行きたい
      if (j != w - 1) {
        if (grid[i][j - 1] == '.' && grid[i][j] == '.')
          g[num + (i * w + j)].pb({num + i * 2 + j + 1, 0});
      }
      if (grid[i][j] == '@')
        continue;
      if (*--se.lower_bound(j) != -1) {
        g[num + i * w + j].pb({num + i * w + (*--se.lower_bound(j)) + 1, 1});
      }
    }
  }
  rep(j, w) {
    set<int> se;
    // したに行きたい
    rep(i, h) {
      if (grid[i][j] == '@')
        se.insert(i);
    }
    se.insert(INF), se.insert(-1);
    rep(i, h) {
      if (i != 0) {
        if (grid[i][j] != '@' && grid[i - 1][j] != '@')
          g[2 * num + i * w + j].pb({2 * num + i * w - w + j, 0});
      }
      if (grid[i][j] == '@')
        continue;
      if (*se.upper_bound(i) != INF) {
        g[2 * num + i * w + j].pb(
            {2 * num + (*se.upper_bound(i) - 1) * w + j, 1});
      }
    }
    // 上に行きたい
    rrep(i, h) {
      if (i != h - 1) {
        if (grid[i][j] != '@' && grid[i + 1][j] != '@')
          g[3 * num + i * w + j].pb({3 * num + i * w + w + j, 0});
      }
      if (grid[i][j] == '@')
        continue;
      if (*--se.lower_bound(i) != -1) {
        g[3 * num + i * w + j].pb(
            {3 * num + (*--se.lower_bound(i) + 1) * w + j, 1});
      }
    }
  }
  auto d = dijkstra(g, sx + sy * w);
  if (d[gx + gy * w] == INF)
    print(-1);
  else if (d[gx + gy * w] == 0)
    print(2);
  else
    print(d[gx + gy * w]);
}