Language: C++

#ifndef DEBUG
#  define NDEBUG
#endif
#include <iostream>
#include <algorithm>
#include <string>
#include <iterator>
#include <utility>
#include <type_traits>
#include <limits>
#include <cassert>
#include <numeric>
#include <vector>
#include <array>
#include <queue>
#include <tuple>

using namespace std;

// template {{{
// misc {{{
using Z = long long;
[[maybe_unused]]
constexpr Z INF = numeric_limits<Z>::max() / 3;
// }}}

// debug {{{
template <class T>
using enable_if_sequence_t = enable_if_t<
  is_same<
    typename iterator_traits<
      typename remove_cv_t<remove_reference_t<T>>::iterator
    >::iterator_category,
    random_access_iterator_tag>{}>;
#ifdef NDEBUG
# define dump(x)
# define debug if (0)
template <class T>
inline T&& ix(T&& value) { return value; }
template <class T, class Index, class... Indices, class = enable_if_sequence_t<T>>
inline auto&& ix(T&& container, Index index, Indices... indices) {
  return ix(container[index], indices...);
}
#else
# define dump(x) do { \
    cerr << "\e[33m[dump: " << __LINE__ << "] " << (#x) << " = " << x << "\e[0m" << endl; \
  } while (0);
# define debug
template <class T>
inline auto&& ix_impl([[maybe_unused]] int line, [[maybe_unused]] const char* code, T&& value) {
  return value;
}
template <class T, class Index, class... Indices, class = enable_if_sequence_t<T>>
inline auto&& ix_impl(int line, const char* code, T&& container, Index index, Indices... indices) {
  if (index < 0) {
    cerr << "\e[31mix: negative index at line " << line << ", ix(" << code << ")\n"
      << "index = " << index << "\e[0m" << endl;
    exit(1);
  }
  int size = distance(begin(container), end(container));
  if (index >= size) {
    cerr << "\e[31mix: index out of range at line " << line << ", ix(" << code << ")\n"
      << "index = " << index << " whereas size = " << size << "\e[0m" << endl;
    exit(1);
  }
  return ix_impl(line, code, container[index], indices...);
}
#define ix(...) ix_impl(__LINE__, #__VA_ARGS__, __VA_ARGS__)
#endif
// }}}

// IO {{{
template <class T, class U>
ostream& operator<< (ostream& os, pair<T, U> p) {
  os << '(' << p.first << ", " << p.second << ')';
  return os;
}
template <class T, class U>
istream& operator>> (istream& is, pair<T, U>& p) {
  is >> p.first >> p.second;
  return is;
}
template <class T>
false_type is_container_impl(...);
template <class T, class = typename T::iterator>
true_type is_container_impl(T);
template <class T>
struct is_container : decltype(is_container_impl<T>(declval<T>())) {};
template <>
struct is_container <string> : std::false_type {};
template <class Container, class = enable_if_t<is_container<Container>{}>>
istream& operator>> (istream& is, Container& cont) {
  for (auto& v : cont) is >> v;
  return is;
}
template <class Container, class = enable_if_t<is_container<Container>{}>>
ostream& operator<< (ostream& os, Container const& cont) {
  bool first = true;
  constexpr char sep =
    is_container<typename Container::value_type>{} ? '\n' : ' ';
  for (auto const& v : cont) {
    if (!first) {
      os << sep;
    }
    first = false;
    os << v;
  }
  return os;
}
template <class T>
void conclude(T const& message) {
  cout << message << endl;
  exit(0);
}
// }}}
// }}}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.precision(10);
  cout << fixed;
  Z N;
  cin >> N;
  vector<Z> Ps(N * N);
  cin >> Ps;
  vector<vector<Z>> costs(N, vector<Z>(N));
  vector<vector<bool>> present(N, vector<bool>(N, true));
  for (auto i = 0; i < N; i++) {
    for (auto j = 0; j < N; j++) {
      ix(costs, i, j) = min<Z>({i, j, N - 1 - i, N - 1 - j});
    }
  }
  Z ans = 0;
  for (auto&& p : Ps) {
    dump(p);
    p--;
    Z x = p / N, y = p % N;
    ans += ix(costs, x, y);
    ix(present, x, y) = false;
    vector<vector<bool>> visited(N, vector<bool>(N));
    ix(visited, x, y) = true;
    queue<tuple<Z, Z, Z>> que;
    que.emplace(x, y, ix(costs, x, y));
    while (!que.empty()) {
      auto [cx, cy, cd] = que.front();
      que.pop();
      dump(cx);
      dump(cy);
      dump(cd);
      constexpr array dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
      for (int i = 0; i < 4; i++) {
        Z nx = cx + ix(dx, i), ny = cy + ix(dy, i);
        if (nx < 0 || nx >= N || ny < 0 || ny >= N || ix(visited, nx, ny)) continue;
        Z nd = cd + (ix(present, cx, cy) ? 1 : 0);
        if (nd >= ix(costs, nx, ny)) {
          continue;
        }
        ix(visited, nx, ny) = true;
        ix(costs, nx, ny) = nd;
        que.emplace(nx, ny, nd);
      }
    }
    dump(present);
    dump(costs);
  }
  cout << ans << '\n';
}


Compiler output:
a.cc: In instantiation of 'T&& ix(T&&) [with T = std::_Bit_reference]':
a.cc:42:12:   recursively required from 'auto&& ix(T&&, Index, Indices ...) [with T = std::vector<bool>&; Index = long long int; Indices = {}; <template-parameter-1-4> = void]'
   42 |   return ix(container[index], indices...);
      |          ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:42:12:   required from 'auto&& ix(T&&, Index, Indices ...) [with T = std::vector<std::vector<bool> >&; Index = long long int; Indices = {long long int}; <template-parameter-1-4> = void]'
a.cc:140:7:   required from here
  140 |     ix(present, x, y) = false;
      |     ~~^~~~~~~~~~~~~~~
a.cc:39:35: error: cannot bind rvalue reference of type 'std::_Bit_reference&&' to lvalue of type 'std::_Bit_reference'
   39 | inline T&& ix(T&& value) { return value; }
      |                                   ^~~~~