Submission #1007115

#	Time	Username	Problem	Language	Result	Execution time	Memory
1007115		NeroZein	Soccer Stadium (IOI23_soccer)	C++17	8 / 100	4558 ms	600 KiB

soccer

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

int n; 
pair<int, int> get(int x) {
  return {x / n, x % n};
}

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

int biggest_stadium(int N_, vector<vector<int>> F) {
  n = N_; 
  vector<vector<int>> ps(n, vector<int> (n));
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j) {
      ps[i][j] = F[i][j];
      if (i) ps[i][j] += ps[i - 1][j];
      if (j) ps[i][j] += ps[i][j - 1];
      if (i && j) ps[i][j] -= ps[i - 1][j - 1];
    }
  }
  auto sum = [&](int x, int y, int i, int j) {
    if (x > i) swap(x, i);
    if (y > j) swap(y, j);
    int ret = ps[i][j];
    if (y) {
      ret -= ps[i][y - 1];      
    }
    if (x) {
      ret -= ps[x - 1][j];      
    }
    if (x && y) {
      ret += ps[x - 1][y - 1];       
    }
    return ret; 
  };
  function<int(int, int, vector<vector<int>>&)> Dfs = [&](int x, int y, vector<vector<int>>& used) {
    if (x < 0 || x >= n || y < 0 || y >= n || !used[x][y]) return 0; 
    used[x][y] = 0; 
    int ret = 1;
    for (int j = 0; j < 4; ++j) {
      int nx = x + dr[j], ny = y + dy[j];
      ret += Dfs(nx, ny, used);
    }
    return ret; 
  };
  int ans = 0; 
  for (int i = 1; i < (1 << (n * n)); ++i) {
    vector<vector<int>> used(n, vector<int> (n));
    bool bad = false; 
    vector<pair<int, int>> vec; 
    int sx = 0, sy = 0;
    for (int j = 0; j < n * n; ++j) {
      if (i >> j & 1) {
        auto [x, y] = get(j);
        sx = x, sy = y;
        vec.emplace_back(x, y); 
        used[x][y] = 1; 
        if (F[x][y]) {
          bad = true; 
        }
      }
    }
    if (bad) {
      continue; 
    }
    bool ok = Dfs(sx, sy, used) == __builtin_popcount(i);
    for (int k = 0; k < (int) vec.size(); ++k) {
      for (int l = 0; l < (int) vec.size(); ++l) {
        if (k == l) continue; 
        auto [x, y] = vec[k];
        auto [xx, yy] = vec[l];
        bool cur = sum(x, y, x, yy) == 0 && sum(x, yy, xx, yy) == 0;
        cur |= sum(x, y, xx, y) == 0 && sum(xx, y, xx, yy) == 0;
        ok &= cur; 
      }
    } 
    if (ok) {
      ans = max(ans, __builtin_popcount(i));
    }
  }
  return ans; 
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 6
• Subtask 2: 8 / 8
• Subtask 3: 0 / 22
• Subtask 4: 0 / 18
• Subtask 5: 0 / 16
• Subtask 6: 0 / 30