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

#include <bits/stdc++.h>
// ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// clock_t start=clock();clock_t
// end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef pair<pii, int> ppii;
typedef pair<int, pii> pipi;
typedef pair<ll, ll> pll;
typedef pair<pll, ll> ppll;
typedef pair<ll, pll> plpl;
typedef pair<pii, pii> pippi;
typedef tuple<ll, ll, ll> tl;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> mat;
ll mod = 1000000007;
ll mod2 = 998244353;
ll mod3 = 1000003;
ll mod4 = 998244853;
ll mod5 = 1000000009;
ll inf = 1LL << 62;
int iinf = 1 << 30;
double pi = 3.141592653589793238462643383279L;
double eps = 1e-8;
#define rep(i, m, n) for (ll i = m; i < n; i++)
#define rrep(i, n, m) for (ll i = n; i >= m; i--)
#define srep(itr, st) for (auto itr = st.begin(); itr != st.end(); itr++)
#define mrep(itr, mp) for (auto &itr : mp)
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
// #define endl "\\n"
int dh[4] = {1, -1, 0, 0};
int dw[4] = {0, 0, 1, -1};
int ddh[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddw[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }

  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
#define umh unordered_map<int, int, custom_hash>
ll gcd(ll a, ll b) {
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  if (a % b == 0)
    return b;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  ll c = gcd(a, b);
  return a * b / c;
}
ll Pow(ll n, ll k) {
  if (k < 0)
    return 0;
  ll ret = 1;
  ll now = n;
  while (k > 0) {
    if (k & 1)
      ret *= now;
    now *= now;
    k /= 2;
  }
  return ret;
}
ll beki(ll n, ll k, ll md) {
  ll ret = 1;
  ll now = n;
  now %= md;
  while (k > 0) {
    if (k % 2 == 1) {
      ret *= now;
      ret %= md;
    }
    now *= now;
    now %= md;
    k /= 2;
  }
  return ret;
}
ll gyaku(ll n, ll md) { return beki(n, md - 2, md); }
ll popcount(ll n) {
  ll ret = 0;
  ll u = n;
  while (u > 0) {
    ret += u % 2;
    u /= 2;
  }
  return ret;
}
typedef pair<pll, pll> P;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ll h, w, k;
  cin >> h >> w >> k;
  ll x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  x1--;
  y1--;
  x2--;
  y2--;
  string s[h];
  rep(i, 0, h) cin >> s[i];
  priority_queue<P, vector<P>, greater<P>> dq;
  dq.push({{0, k}, {x1, y1}});
  pll mi[h][w];
  ll mii[h][w][4];
  rep(i, 0, h) {
    rep(j, 0, w) {
      mi[i][j] = {inf, inf};
      rep(l, 0, 4) mii[i][j][l] = inf;
    }
  }
  mi[x1][y1] = {0, k};
  mii[x1][y1][0] = k;
  ll ans = inf;
  while (dq.size() > 0) {
    P p = dq.top();
    dq.pop();
    ll dis = p.first.first, num = p.first.second, nh = p.second.first,
       nw = p.second.second;
    if (nh == x2 && nw == y2) {

      Min(ans, dis);
      continue;
    }
    ll dire = num / 2000000;
    num %= 2000000;

    rep(i, 0, 4) {
      ll nnh = nh + dh[i], nnw = nw + dw[i];
      if (nnh < 0 || nnh >= h || nnw < 0 || nnw >= w)
        continue;
      if (s[nnh][nnw] == '@')
        continue;
      ll co = 1;
      if (i == dire && num <= k - 1)
        co = 0;
      ll nn = num + 1;
      if (co == 1)
        nn = 1;
      if (mi[nnh][nnw].first < dis + co)
        continue;
      else if (mi[nnh][nnw].first == dis + co) {
        if (mii[nnh][nnw][i] <= nn)
          continue;
      }
      mi[nnh][nnw] = {dis + co, nn};
      mii[nnh][nnw][i] = nn;
      if (co == 0) {
        dq.push({{dis, i * 2000000 + num + 1}, {nnh, nnw}});
      } else {
        if (i == dire)
          dq.push({{dis + 1, i * 2000000 + 1}, {nnh, nnw}});
        else
          dq.push({{dis + 1, i * 2000000 + 1}, {nnh, nnw}});
      }
    }
  }
  if (ans == inf)
    ans = -1;
  cout << ans << endl;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
// ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// clock_t start=clock();clock_t
// end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef pair<pii, int> ppii;
typedef pair<int, pii> pipi;
typedef pair<ll, ll> pll;
typedef pair<pll, ll> ppll;
typedef pair<ll, pll> plpl;
typedef pair<pii, pii> pippi;
typedef tuple<ll, ll, ll> tl;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> mat;
ll mod = 1000000007;
ll mod2 = 998244353;
ll mod3 = 1000003;
ll mod4 = 998244853;
ll mod5 = 1000000009;
ll inf = 1LL << 62;
int iinf = 1 << 30;
double pi = 3.141592653589793238462643383279L;
double eps = 1e-8;
#define rep(i, m, n) for (int i = m; i < n; i++)
#define rrep(i, n, m) for (ll i = n; i >= m; i--)
#define srep(itr, st) for (auto itr = st.begin(); itr != st.end(); itr++)
#define mrep(itr, mp) for (auto &itr : mp)
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
// #define endl "\\n"
int dh[4] = {1, -1, 0, 0};
int dw[4] = {0, 0, 1, -1};
int ddh[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddw[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }

  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
#define umh unordered_map<int, int, custom_hash>
ll gcd(ll a, ll b) {
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  if (a % b == 0)
    return b;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  ll c = gcd(a, b);
  return a * b / c;
}
ll Pow(ll n, ll k) {
  if (k < 0)
    return 0;
  ll ret = 1;
  ll now = n;
  while (k > 0) {
    if (k & 1)
      ret *= now;
    now *= now;
    k /= 2;
  }
  return ret;
}
ll beki(ll n, ll k, ll md) {
  ll ret = 1;
  ll now = n;
  now %= md;
  while (k > 0) {
    if (k % 2 == 1) {
      ret *= now;
      ret %= md;
    }
    now *= now;
    now %= md;
    k /= 2;
  }
  return ret;
}
ll gyaku(ll n, ll md) { return beki(n, md - 2, md); }
ll popcount(ll n) {
  ll ret = 0;
  ll u = n;
  while (u > 0) {
    ret += u % 2;
    u /= 2;
  }
  return ret;
}
typedef pair<pii, pii> P;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int h, w, k;
  cin >> h >> w >> k;
  int x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  x1--;
  y1--;
  x2--;
  y2--;
  string s[h];
  rep(i, 0, h) cin >> s[i];
  deque<P> dq;
  dq.push_back({{0, k}, {x1, y1}});
  int mi[h][w];
  rep(i, 0, h) { rep(j, 0, w) mi[i][j] = 1000000000; }
  mi[x1][y1] = 0;
  while (dq.size() > 0) {
    P p = dq.front();
    dq.pop_front();
    int dis = p.first.first, num = p.first.second, nh = p.second.first,
        nw = p.second.second;
    if (nh == x2 && nw == y2) {

      cout << dis << endl;
      return 0;
    }
    int dire = num / 2000000;
    num %= 2000000;
    if (nh == 2 && nw == 0) {
      // cout<<dis<<" "<<num<<" "<<dire<<endl;
    }
    rep(i, 0, 4) {
      int nnh = nh + dh[i], nnw = nw + dw[i];
      if (nnh < 0 || nnh >= h || nnw < 0 || nnw >= w)
        continue;
      if (s[nnh][nnw] == '@')
        continue;
      int co = 1;
      if (i == dire && num <= k - 1)
        co = 0;
      if (mi[nnh][nnw] < dis + co)
        continue;
      mi[nnh][nnw] = dis + co;
      if (co == 0) {
        dq.push_front({{dis, i * 2000000 + num + 1}, {nnh, nnw}});
      } else {
        if (i == dire)
          dq.push_back({{dis + 1, i * 2000000 + 1}, {nnh, nnw}});
        else
          dq.push_back({{dis + 1, i * 2000000 + 1}, {nnh, nnw}});
      }
    }
  }
  cout << -1 << endl;
}