Problem p02644 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<ll, ll>;
using Pld = pair<ld, ld>;
using Vec = vector<ll>;
using VecP = vector<P>;
using VecB = vector<bool>;
using VecC = vector<char>;
using VecD = vector<ld>;
using VecS = vector<string>;
using Graph = vector<VecP>;
template <typename T> using Vec1 = vector<T>;
template <typename T> using Vec2 = vector<Vec1<T>>;
#define REP(i, m, n) for (ll i = (m); (i) < (n); ++(i))
#define REPN(i, m, n) for (ll i = (m); (i) <= (n); ++(i))
#define REPR(i, m, n) for (ll i = (m)-1; (i) >= (n); --(i))
#define REPNR(i, m, n) for (ll i = (m); (i) >= (n); --(i))
#define rep(i, n) REP(i, 0, n)
#define repn(i, n) REPN(i, 1, n)
#define repr(i, n) REPR(i, n, 0)
#define repnr(i, n) REPNR(i, n, 1)
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define fs first
#define sc second
template <typename T> bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> bool chmin(T &a, const T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> ll pow2(const T n) { return (1LL << n); }
template <typename T> void cosp(const T n) { cout << n << ' '; }
void co(void) { cout << '\\n'; }
template <typename T> void co(const T n) { cout << n << '\\n'; }
template <typename T1, typename T2> void co(pair<T1, T2> p) {
  cout << p.fs << ' ' << p.sc << '\\n';
}
template <typename T> void co(const Vec1<T> &v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void co(initializer_list<T> v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void ce(const T n) { cerr << n << endl; }
void sonic() {
  ios::sync_with_stdio(false);
  cin.tie(0);
}
void setp(const ll n) { cout << fixed << setprecision(n); }
constexpr int INF = 1e9 + 1;
constexpr ll LINF = 1e18 + 1;
constexpr ll MOD = 1e9 + 7;
// constexpr ll MOD = 998244353;
constexpr ld EPS = 1e-11;
const ld PI = acos(-1);

int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};

VecS board;
Vec2<ll> dist;
ll h, w, k;
ll x1, y_1, x2, y2;

bool inBoard(ll x, ll y) {
  return x >= 0 && x < h && y >= 0 && y < w && board[x][y] == '.';
}

ll solve() {
  queue<P> que;
  que.push({x1, y_1});
  while (!que.empty()) {
    P p = que.front();
    que.pop();
    ll d = dist[p.fs][p.sc];
    rep(i, 4) {
      ll x = p.fs, y = p.sc;
      rep(j, k) {
        x += dx[i], y += dy[i];
        if (inBoard(x, y) && chmin(dist[x][y], d + 1)) {
          que.push({x, y});
        } else if (inBoard(x, y) && dist[x][y] == d + 1)
          continue;
        else
          break;
      }
    }
  }
  return dist[x2][y2];
}

int main(void) {
  cin >> h >> w >> k;
  board.resize(h);
  dist.resize(h);
  rep(i, h) dist[i].assign(w, LINF);
  cin >> x1 >> y_1 >> x2 >> y2;
  x1--, y_1--, x2--, y2--;
  dist[x1][y_1] = 0;

  rep(i, h) cin >> board[i];

  ll ans = solve();
  if (ans != LINF)
    co(ans);
  else
    co(-1);
  // rep(i, h) co(dist[i]);

  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<ll, ll>;
using Pld = pair<ld, ld>;
using Vec = vector<ll>;
using VecP = vector<P>;
using VecB = vector<bool>;
using VecC = vector<char>;
using VecD = vector<ld>;
using VecS = vector<string>;
using Graph = vector<VecP>;
template <typename T> using Vec1 = vector<T>;
template <typename T> using Vec2 = vector<Vec1<T>>;
#define REP(i, m, n) for (ll i = (m); (i) < (n); ++(i))
#define REPN(i, m, n) for (ll i = (m); (i) <= (n); ++(i))
#define REPR(i, m, n) for (ll i = (m)-1; (i) >= (n); --(i))
#define REPNR(i, m, n) for (ll i = (m); (i) >= (n); --(i))
#define rep(i, n) REP(i, 0, n)
#define repn(i, n) REPN(i, 1, n)
#define repr(i, n) REPR(i, n, 0)
#define repnr(i, n) REPNR(i, n, 1)
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define fs first
#define sc second
template <typename T> bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> bool chmin(T &a, const T b) {
  if (a >= b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> ll pow2(const T n) { return (1LL << n); }
template <typename T> void cosp(const T n) { cout << n << ' '; }
void co(void) { cout << '\\n'; }
template <typename T> void co(const T n) { cout << n << '\\n'; }
template <typename T1, typename T2> void co(pair<T1, T2> p) {
  cout << p.fs << ' ' << p.sc << '\\n';
}
template <typename T> void co(const Vec1<T> &v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void co(initializer_list<T> v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void ce(const T n) { cerr << n << endl; }
void sonic() {
  ios::sync_with_stdio(false);
  cin.tie(0);
}
void setp(const ll n) { cout << fixed << setprecision(n); }
constexpr int INF = 1e9 + 1;
constexpr ll LINF = 1e18 + 1;
constexpr ll MOD = 1e9 + 7;
// constexpr ll MOD = 998244353;
constexpr ld EPS = 1e-11;
const ld PI = acos(-1);

int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};

VecS board;
Vec2<ll> dist;
ll h, w, k;
ll x1, y_1, x2, y2;

bool inBoard(ll x, ll y) {
  return x >= 0 && x < h && y >= 0 && y < w && board[x][y] == '.';
}

ll solve() {
  queue<P> que;
  que.push({x1, y_1});
  while (!que.empty()) {
    P p = que.front();
    que.pop();
    ll d = dist[p.fs][p.sc];
    rep(i, 4) {
      ll x = p.fs, y = p.sc;
      rep(j, k) {
        x += dx[i], y += dy[i];
        if (inBoard(x, y) && chmin(dist[x][y], d + 1)) {
          que.push({x, y});
        } else
          break;
      }
    }
  }
  return dist[x2][y2];
}

int main(void) {
  cin >> h >> w >> k;
  board.resize(h);
  dist.resize(h);
  rep(i, h) dist[i].assign(w, LINF);
  cin >> x1 >> y_1 >> x2 >> y2;
  x1--, y_1--, x2--, y2--;
  dist[x1][y_1] = 0;

  rep(i, h) cin >> board[i];

  ll ans = solve();
  if (ans != LINF)
    co(ans);
  else
    co(-1);
  // rep(i, h) co(dist[i]);

  return 0;
}