Problem p02670 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cassert>
#include <ciso646>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;

// #define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 998244353;
const ll INF = mod * mod;
typedef pair<int, int> P;
#define stop                                                                   \\
  char nyaa;                                                                   \\
  cin >> nyaa;
#define rep(i, n) for (int i = 0; i < n; i++)
#define per(i, n) for (int i = n - 1; i >= 0; i--)
#define Rep(i, sta, n) for (int i = sta; i < n; i++)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define per1(i, n) for (int i = n; i >= 1; i--)
#define Rep1(i, sta, n) for (int i = sta; i <= n; i++)
#define all(v) (v).begin(), (v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);

void chmin(int &a, int b) { a = min(a, b); }
void chmax(int &a, int b) { a = max(a, b); }
ll mod_pow(ll a, ll n, ll m = mod) {
  a %= m;
  ll res = 1;
  while (n) {
    if (n & 1)
      res = res * a % m;
    a = a * a % m;
    n >>= 1;
  }
  return res;
}

struct modint {
  ll n;
  modint() : n(0) { ; }
  modint(ll m) : n(m) {
    if (n >= mod)
      n %= mod;
    else if (n < 0)
      n = (n % mod + mod) % mod;
  }
  operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) {
  a.n += b.n;
  if (a.n >= mod)
    a.n -= mod;
  return a;
}
modint operator-=(modint &a, modint b) {
  a.n -= b.n;
  if (a.n < 0)
    a.n += mod;
  return a;
}
modint operator*=(modint &a, modint b) {
  a.n = ((ll)a.n * b.n) % mod;
  return a;
}
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
  if (n == 0)
    return modint(1);
  modint res = (a * a) ^ (n / 2);
  if (n % 2)
    res = res * a;
  return res;
}

ll inv(ll a, ll p) { return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p); }
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
  fact[0] = modint(1);
  for (int i = 0; i < max_n - 1; i++) {
    fact[i + 1] = fact[i] * modint(i + 1);
  }
  factinv[max_n - 1] = modint(1) / fact[max_n - 1];
  for (int i = max_n - 2; i >= 0; i--) {
    factinv[i] = factinv[i + 1] * modint(i + 1);
  }
}
modint comb(int a, int b) {
  if (a < 0 || b < 0 || a < b)
    return 0;
  return fact[a] * factinv[b] * factinv[a - b];
}

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

int dist[500][500];
bool exi[500][500];

void solve() {
  int n;
  cin >> n;
  vector<int> p(n * n);
  rep(i, n * n) {
    cin >> p[i];
    p[i]--;
  }
  rep(i, n) rep(j, n) {
    dist[i][j] = min({i, j, n - 1 - i, n - 1 - j});
    exi[i][j] = true;
  }
  ll ans = 0;
  rep(i, n * n) {
    int x = p[i] / n;
    int y = p[i] % n;
    ans += dist[x][y];
    exi[x][y] = false;
    queue<P> q;
    q.push({x, y});
    while (!q.empty()) {
      P p = q.front();
      q.pop();
      x = p.first, y = p.second;
      rep(d, 4) {
        int nx = x + dx[d], ny = y + dy[d];
        if (nx < 0 || ny < 0 || nx == n || ny == n)
          continue;
        int nd = dist[x][y] + (exi[x][y]);

        if (nd < dist[nx][ny]) {
          dist[nx][ny] = nd;
          q.push({nx, ny});
        }
      }
    }
  }
  cout << ans << "\\n";
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  // cout << fixed << setprecision(10);
  // init_f();
  // init();
  solve();
  stop return 0;
}


Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cassert>
#include <ciso646>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;

// #define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int> P;
#define stop                                                                   \\
  char nyaa;                                                                   \\
  cin >> nyaa;
#define rep(i, n) for (int i = 0; i < n; i++)
#define per(i, n) for (int i = n - 1; i >= 0; i--)
#define Rep(i, sta, n) for (int i = sta; i < n; i++)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define per1(i, n) for (int i = n; i >= 1; i--)
#define Rep1(i, sta, n) for (int i = sta; i <= n; i++)
#define all(v) (v).begin(), (v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);

void chmin(ll &a, ll b) { a = min(a, b); }
void chmax(ll &a, ll b) { a = max(a, b); }
ll mod_pow(ll a, ll n, ll m = mod) {
  a %= m;
  ll res = 1;
  while (n) {
    if (n & 1)
      res = res * a % m;
    a = a * a % m;
    n >>= 1;
  }
  return res;
}

struct modint {
  ll n;
  modint() : n(0) { ; }
  modint(ll m) : n(m) {
    if (n >= mod)
      n %= mod;
    else if (n < 0)
      n = (n % mod + mod) % mod;
  }
  operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) {
  a.n += b.n;
  if (a.n >= mod)
    a.n -= mod;
  return a;
}
modint operator-=(modint &a, modint b) {
  a.n -= b.n;
  if (a.n < 0)
    a.n += mod;
  return a;
}
modint operator*=(modint &a, modint b) {
  a.n = ((ll)a.n * b.n) % mod;
  return a;
}
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
  if (n == 0)
    return modint(1);
  modint res = (a * a) ^ (n / 2);
  if (n % 2)
    res = res * a;
  return res;
}

ll inv(ll a, ll p) { return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p); }
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
  fact[0] = modint(1);
  for (int i = 0; i < max_n - 1; i++) {
    fact[i + 1] = fact[i] * modint(i + 1);
  }
  factinv[max_n - 1] = modint(1) / fact[max_n - 1];
  for (int i = max_n - 2; i >= 0; i--) {
    factinv[i] = factinv[i + 1] * modint(i + 1);
  }
}
modint comb(int a, int b) {
  if (a < 0 || b < 0 || a < b)
    return 0;
  return fact[a] * factinv[b] * factinv[a - b];
}

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

int a[500][500];

int id[500][500][251];

queue<P> qs[250002];
bool used[500][500];
void solve() {
  int n;
  cin >> n;
  vector<int> in(n * n);
  rep(i, n * n) cin >> in[i];
  rep(i, n * n) {
    in[i]--;
    a[in[i] / n][in[i] % n] = i + 1;
  }
  /*rep(i, n) {
          rep(j, n) {
                  cout << a[i][j] << " ";
          }
          cout << "\\n";
  }*/

  int sz = n / 2;

  int sup = n * n + 1;
  rep(i, n) rep(j, n) rep(k, sz + 1) id[i][j][k] = sup;
  rep(i, n) rep(j, n) {
    if (i == 0 || j == 0 || i == n - 1 || j == n - 1) {
      id[i][j][0] = a[i][j];
      id[i][j][1] = 0;
    }
  }
  rep(k, sz + 1) {

    rep(i, n) rep(j, n) used[i][j] = false;
    rep(i, n) rep(j, n) {
      if (id[i][j][k] == sup) {
        // used[i][j] = true;
        continue;
      }
      if (k > 0 && id[i][j][k] == id[i][j][k - 1]) {
        // used[i][j] = true;
        continue;
      }
      qs[id[i][j][k]].push({i, j});
    }
    rep(t, sup) {
      while (!qs[t].empty()) {
        P p = qs[t].front();
        qs[t].pop();
        int x = p.first, y = p.second;
        if (used[x][y])
          continue;
        used[x][y] = true;
        rep(d, 4) {
          int nx = x + dx[d], ny = y + dy[d];
          if (nx < 0 || ny < 0 || nx == n || ny == n)
            continue;
          if (used[nx][ny])
            continue;
          // if (a[nx][ny] < id[x][y][k])continue;
          int td = max(a[nx][ny], id[x][y][k]);
          if (td < id[nx][ny][k]) {
            id[nx][ny][k] = td;
            qs[td].push({nx, ny});
          }
        }
      }
    }
    while (!qs[sup].empty())
      qs[sup].pop();
    if (k < sz) {
      rep(x, n) rep(y, n) {

        rep(d, 4) {
          int nx = x + dx[d], ny = y + dy[d];
          if (nx < 0 || ny < 0 || nx == n || ny == n)
            continue;
          id[nx][ny][k + 1] = min(id[nx][ny][k + 1], id[x][y][k]);
        }
      }
    }
  }
  ll ans = 0;
  rep(i, n) rep(j, n) {
    int z = 0;
    rep(k, n + 1) if (id[i][j][k] == a[i][j]) {
      z = k;
      break;
    }
    // cout << "? " << a[i][j] << " " << z << "\\n";
    ans += z;
  }
  cout << ans << "\\n";
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  // cout << fixed << setprecision(10);
  // init_f();
  // init();
  // int t; cin >> t;rep(i, t)solve();
  solve();
  stop return 0;
}