Problem p02670 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
using namespace std;
using ll = long long;
using ld = long double;
using V = vector<int>;
using Vll = vector<ll>;
using Vld = vector<ld>;
using Vbo = vector<bool>;
using VV = vector<V>;
using VVll = vector<Vll>;
using VVld = vector<Vld>;
using VVbo = vector<Vbo>;
using VVV = vector<VV>;
using VVVll = vector<VVll>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using Pld = pair<ld, ld>;
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define rep(i, n) rep2(i, 0, n)
#define drep(i, n) drep2(i, n, 0)
#define all(a) (a).begin(), (a).end()
struct fast_ios {
  fast_ios() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
template <typename T> inline int sz(T &x) { return x.size(); }
template <typename T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << '(' << p.first << ", " << p.second << ')';
  return os;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &e : v)
    is >> e;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (auto &e : v)
    os << e << ' ';
  return os;
}
template <typename T> inline int count_between(vector<T> &a, T l, T r) {
  return lower_bound(all(a), r) - lower_bound(all(a), l);
} // [l, r)
inline int fLog2(const int x) {
  assert(x > 0);
  return 31 - __builtin_clz(x);
} // floor(log2(x))
inline int fLog2(const ll x) {
  assert(x > 0);
  return 63 - __builtin_clzll(x);
}
inline int cLog2(const int x) {
  assert(x > 0);
  return (x == 1) ? 0 : 32 - __builtin_clz(x - 1);
} // ceil(log2(x))
inline int cLog2(const ll x) {
  assert(x > 0);
  return (x == 1) ? 0 : 64 - __builtin_clzll(x - 1);
}
inline int popcount(const int x) { return __builtin_popcount(x); }
inline int popcount(const ll x) { return __builtin_popcountll(x); }
void fail() {
  puts("-1");
  exit(0);
}

const V dx = {1, 0, -1, 0};
const V dy = {0, 1, 0, -1};

int main() {
  int n;
  cin >> n;

  ll ans = 0;
  VV occ(n, V(n, 1));
  VV d(n, V(n));
  rep(i, n) rep(j, n) d[i][j] = min({i, n - i - 1, j, n - j - 1});

  rep(i, n * n) {
    int p;
    cin >> p;
    --p;
    int si = p / n;
    int sj = p % n;
    queue<P> que;
    que.emplace(si, sj);
    ans += d[si][sj];
    occ[si][sj] = 0;

    while (!que.empty()) {
      auto [i, j] = que.front();
      que.pop();
      rep(dir, sz(dx)) {
        int ii = i + dx[dir];
        int jj = j + dy[dir];
        if (ii < 0 || ii >= n || jj < 0 || jj >= n)
          continue;
        int dd = d[i][j] + occ[i][j];
        if (chmin(d[ii][jj], dd)) {
          que.emplace(ii, jj);
        }
      }
    }
  }

  cout << ans << "\\n";
  return 0;
}


Error: -11

Fixed submission:

#include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
using namespace std;
using ll = long long;
using ld = long double;
using V = vector<int>;
using Vll = vector<ll>;
using Vld = vector<ld>;
using Vbo = vector<bool>;
using VV = vector<V>;
using VVll = vector<Vll>;
using VVld = vector<Vld>;
using VVbo = vector<Vbo>;
using VVV = vector<VV>;
using VVVll = vector<VVll>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using Pld = pair<ld, ld>;
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define rep(i, n) rep2(i, 0, n)
#define drep(i, n) drep2(i, n, 0)
#define all(a) (a).begin(), (a).end()
struct fast_ios {
  fast_ios() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
template <typename T> inline int sz(T &x) { return x.size(); }
template <typename T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << '(' << p.first << ", " << p.second << ')';
  return os;
}
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &e : v)
    is >> e;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (auto &e : v)
    os << e << ' ';
  return os;
}
template <typename T> inline int count_between(vector<T> &a, T l, T r) {
  return lower_bound(all(a), r) - lower_bound(all(a), l);
} // [l, r)
inline int fLog2(const int x) {
  assert(x > 0);
  return 31 - __builtin_clz(x);
} // floor(log2(x))
inline int fLog2(const ll x) {
  assert(x > 0);
  return 63 - __builtin_clzll(x);
}
inline int cLog2(const int x) {
  assert(x > 0);
  return (x == 1) ? 0 : 32 - __builtin_clz(x - 1);
} // ceil(log2(x))
inline int cLog2(const ll x) {
  assert(x > 0);
  return (x == 1) ? 0 : 64 - __builtin_clzll(x - 1);
}
inline int popcount(const int x) { return __builtin_popcount(x); }
inline int popcount(const ll x) { return __builtin_popcountll(x); }
void fail() {
  puts("-1");
  exit(0);
}

const V dx = {1, 0, -1, 0};
const V dy = {0, 1, 0, -1};

int main() {
  int n;
  cin >> n;

  ll ans = 0;
  VV ocu(n, V(n, 1));
  VV d(n, V(n));
  rep(i, n) rep(j, n) d[i][j] = min({i, n - i - 1, j, n - j - 1});

  rep(i, n * n) {
    int p;
    cin >> p;
    int si = p / n;
    int sj = p % n;
    queue<P> que;
    que.emplace(si, sj);
    ans += d[si][sj];
    ocu[si][sj] = 0;

    while (!que.empty()) {
      auto [i, j] = que.front();
      que.pop();
      rep(dir, sz(dx)) {
        int ii = i + dx[dir];
        int jj = j + dy[dir];
        if (ii < 0 || ii >= n || jj < 0 || jj >= n)
          continue;
        int dd = d[i][j] + ocu[i][j];
        if (chmin(d[ii][jj], dd)) {
          que.emplace(ii, jj);
        }
      }
    }
  }

  cout << ans << "\\n";
  return 0;
}