Submission #827942

#	Time	Username	Problem	Language	Result	Execution time	Memory
827942		null_awe	Maze (JOI23_ho_t3)	C++14	43 / 100	2096 ms	433544 KiB

Main

#include <bits/stdc++.h>
using namespace std;

#define pii pair<int, int>

const int UNTIL = 4206900;

vector<int> dx = {-1, 1, 0, 0}, dy = {0, 0, -1, 1};

int LG2[UNTIL];

int csqrt[UNTIL], fsqrt[UNTIL];

void init() {
  LG2[1] = 0;
  for (int i = 2; i < UNTIL; ++i) LG2[i] = LG2[i >> 1] + 1;
  csqrt[1] = fsqrt[1] = 1;
  for (int i = 2; i < UNTIL; ++i) {
    fsqrt[i] = fsqrt[i - 1];
    while ((fsqrt[i] + 1) * (fsqrt[i] + 1) <= i) ++fsqrt[i];
    csqrt[i] = fsqrt[i];
    if (fsqrt[i] * fsqrt[i] < i) ++csqrt[i];
  }
}

struct VEB {

  int u, mn, mx, sz;
  VEB *summary;
  vector<VEB*> galaxy;

  inline int high(int k) { return k / sz; }
  inline int low(int k) { return k % sz; }
  inline int index(int k, int kk) { return k * sz + kk; }

  VEB(int u) : u(u) {
    mn = INT_MAX, mx = INT_MIN;
    if (u <= 2) summary = nullptr, galaxy.resize(0, nullptr);
    else {
      int ngalaxy = csqrt[u];
      sz = (u + ngalaxy - 1) / ngalaxy;
      summary = new VEB(ngalaxy);
      galaxy.resize(ngalaxy, nullptr);
      for (int i = 0; i < ngalaxy - 1; ++i) galaxy[i] = new VEB(sz);
      galaxy[ngalaxy - 1] = new VEB(u - (ngalaxy - 1) * sz);
    }
  }

  void insert(int x) {
    if (mn == INT_MAX) mn = mx = x;
    else {
      if (x < mn) swap(x, mn);
      if (x > mx) mx = x;
      if (u <= 2) return;
      int i = high(x), j = low(x);
      if (galaxy[i]->mn == INT_MAX) summary->insert(i);
      galaxy[i]->insert(j);
    }
  }

  void erase(int x) {
    if (mn == INT_MAX) return;
    if (mn == mx) {
      mn = INT_MAX, mx = INT_MIN;
      return;
    }
    if (u <= 2) {
      if (x != mx) mn = mx;
      else if (x == mn) mn = INT_MAX, mx = INT_MIN;
      else if (x == 0) mn = 1;
      else mx = 0;
      return;
    }
    if (x == mn) {
      int i = summary->mn;
      if (i == INT_MAX) {
        mn = INT_MAX, mx = INT_MIN;
        return;
      }
      x = mn = index(i, galaxy[i]->mn);
    }
    int i = high(x), j = low(x);
    galaxy[i]->erase(j);
    if (galaxy[i]->mn == INT_MAX) summary->erase(i);
    if (x == mx) {
      if (summary->mx == INT_MIN) mx = mn;
      else {
        i = summary->mx;
        mx = index(i, galaxy[i]->mx);
      }
    }
  }

  int lower_bound(int x) {
    if (x <= mn) return mn;
    if (u <= 2) {
      if (x <= mx) return mx;
      return INT_MAX;
    }
    int i = high(x), j = low(x);
    if (j <= galaxy[i]->mx) j = galaxy[i]->lower_bound(j);
    else {
      i = summary->lower_bound(i + 1);
      j = galaxy[i]->mn;
    }
    return index(i, j);
  }
};

VEB* build_veb(int u) {
  VEB* root = new VEB(u);
  for (int i = 0; i < u; ++i) root->insert(i);
  return root;
}

struct Sustree {

  int n, m;
  vector<VEB*> has;

  Sustree() {}

  Sustree(int n, int m) : n(n), m(m), has(4 * n, nullptr) {}

  void build(int t, int tl, int tr) {
    has[t] = build_veb(m + 1);
    if (tl == tr) return;
    build(2 * t, tl, (tl + tr) / 2);
    build(2 * t + 1, (tl + tr) / 2 + 1, tr);
  }

  void build() {
    build(1, 0, n - 1);
  }


  void upd(int t, int tl, int tr, int p, int py) {
    if (tl == tr) {
      has[t]->erase(py);
      return;
    }
    if (p <= (tl + tr) / 2) upd(2 * t, tl, (tl + tr) / 2, p, py);
    else upd(2 * t + 1, (tl + tr) / 2 + 1, tr, p, py);
    int a = has[2 * t]->lower_bound(py);
    int b = has[2 * t + 1]->lower_bound(py);
    if (a != py && b != py) {
      has[t]->erase(py);
    }
  }

  void upd(int x, int y) {
    upd(1, 0, n - 1, x, y);
  }

  pii qry(int t, int tl, int tr, int l, int r, int lo, int hi) {
    l = max(l, tl), r = min(r, tr);
    if (l > r) return {-1, -1};
    if (tl == l && tr == r) {
      int gr = has[t]->lower_bound(lo);
      if (gr > hi) return {-1, -1};
      if (tl == tr) {
        return {tl, gr};
      }
      int mm = (tl + tr) / 2;
      if (has[2 * t]->lower_bound(lo) <= hi) return qry(2 * t, tl, mm, l, r, lo, hi);
      return qry(2 * t + 1, mm + 1, tr, l, r, lo, hi);
    }
    int mm = (tl + tr) / 2;
    pii f = qry(2 * t, tl, mm, l, r, lo, hi);
    if (f.first >= 0) return f;
    return qry(2 * t + 1, mm + 1, tr, l, r, lo, hi);
  }

  pii qry(int x1, int y1, int x2, int y2) {
    return qry(1, 0, n - 1, max(x1, 0), min(x2, n - 1), max(y1, 0), min(y2, m - 1));
  }
};

int main() {
  init();
  ios_base::sync_with_stdio(false); cin.tie(NULL);
  int r, c, n; cin >> r >> c >> n;
  int sx, sy; cin >> sx >> sy; --sx, --sy;
  int gx, gy; cin >> gx >> gy; --gx, --gy;
  vector<string> arr(r);
  for (int i = 0; i < r; ++i) cin >> arr[i];
  if (r > c) {
    vector<string> arr2(c);
    for (int i = 0; i < r; ++i) {
      for (int j = 0; j < c; ++j) {
        arr2[j] += arr[i][j];
      }
    }
    swap(arr, arr2);
    swap(r, c);
    swap(sx, sy);
    swap(gx, gy);
  }
  // . = empty
  // # = wall
  Sustree sus(r, c); sus.build();
  vector<vector<int>> dists(r, vector<int>(c, INT_MAX));
  dists[sx][sy] = 0;
  sus.upd(sx, sy);
  vector<pii> q; q.push_back({sx, sy});
  queue<pii> rq; for (pii _p : q) rq.push(_p);
  while (rq.size()) {
    pii front = rq.front(); rq.pop();
    int xx = front.first, yy = front.second;
    for (int d = 0; d < 4; ++d) {
      int nx = xx + dx[d], ny = yy + dy[d];
      if (nx < 0 || ny < 0 || nx >= r || ny >= c) continue;
      if (dists[nx][ny] < INT_MAX || arr[nx][ny] == '#') continue;
      rq.push({nx, ny});
      q.push_back({nx, ny});
      dists[nx][ny] = dists[xx][yy];
      sus.upd(nx, ny);
    }
  }
  while (q.size()) {
    vector<pii> nq;
    for (pii p : q) {
      int x = p.first, y = p.second;
      if (x > 0 && dists[x - 1][y] <= dists[x][y]) {
        // query down:
        int cur;
        while ((cur = sus.qry(x + n, y - n + 1, x + n, y + n - 1).second) != -1) {
          nq.push_back({x + n, cur});
          dists[x + n][cur] = dists[x][y] + 1;
          sus.upd(x + n, cur);
        }
        if (x + n - 1 < r && y - n >= 0 && dists[x + n - 1][y - n] == INT_MAX) {
          nq.push_back({x + n - 1, y - n});
          dists[x + n - 1][y - n] = dists[x][y] + 1;
          sus.upd(x + n - 1, y - n);
        }
        if (x + n - 1 < r && y + n < c && dists[x + n - 1][y + n] == INT_MAX) {
          nq.push_back({x + n - 1, y + n});
          dists[x + n - 1][y + n] = dists[x][y] + 1;
          sus.upd(x + n - 1, y + n);
        }
      } else if (y < r - 1 && dists[x][y + 1] <= dists[x][y]) {
        // query left:
        int cur;
        while ((cur = sus.qry(x - n + 1, y - n, x + n - 1, y - n).first) != -1) {
          nq.push_back({cur, y - n});
          dists[cur][y - n] = dists[x][y] + 1;
          sus.upd(cur, y - n);
        }
        if (y - n + 1 >= 0 && x - n >= 0 && dists[x - n][y - n + 1] == INT_MAX) {
          nq.push_back({x - n, y - n + 1});
          dists[x - n][y - n + 1] = dists[x][y] + 1;
          sus.upd(x - n, y - n + 1);
        }
        if (y - n + 1 >= 0 && x + n < r && dists[x + n][y - n + 1] == INT_MAX) {
          nq.push_back({x + n, y - n + 1});
          dists[x + n][y - n + 1] = dists[x][y] + 1;
          sus.upd(x + n, y - n + 1);
        }
      } else {
        // query all:
        for (int i = -n; i <= n; i += 2 * n) {
          int cx = x + i, cyl = y - n + 1, cyr = y + n - 1, cur;
          while ((cur = sus.qry(cx, cyl, cx, cyr).second) != -1) {
            nq.push_back({cx, cur});
            dists[cx][cur] = dists[x][y] + 1;
            sus.upd(cx, cur);
          }
        }
        pii cur;
        while ((cur = sus.qry(x - n + 1, y - n, x + n - 1, y + n)).first != -1) {
          int nx = cur.first, ny = cur.second;
          nq.push_back({nx, ny});
          dists[nx][ny] = dists[x][y] + 1;
          sus.upd(nx, ny);
        }
      }
    }
    queue<pii> rq; for (pii _p : nq) rq.push(_p);
    while (rq.size()) {
      pii front = rq.front(); rq.pop();
      int xx = front.first, yy = front.second;
      for (int d = 0; d < 4; ++d) {
        int nx = xx + dx[d], ny = yy + dy[d];
        if (nx < 0 || ny < 0 || nx >= r || ny >= c) continue;
        if (dists[nx][ny] < INT_MAX || arr[nx][ny] == '#') continue;
        rq.push({nx, ny});
        nq.push_back({nx, ny});
        dists[nx][ny] = dists[xx][yy];
        sus.upd(nx, ny);
      }
    }
    q = nq;
  }
  cout << dists[gx][gy] << '\n';
  return 0;
}

Compilation message (stderr)

Main.cpp:12:5: warning: built-in function 'csqrt' declared as non-function [-Wbuiltin-declaration-mismatch]
   12 | int csqrt[UNTIL], fsqrt[UNTIL];
      |     ^~~~~

• Subtask 1: 0 / 8
• Subtask 2: 19 / 19
• Subtask 3: 0 / 16
• Subtask 4: 19 / 19
• Subtask 5: 5 / 5
• Subtask 6: 0 / 19
• Subtask 7: 0 / 8
• Subtask 8: 0 / 6