Submission #1253969

#	Time	Username	Problem	Language	Result	Execution time	Memory
1253969		LucaLucaM	Maze (JOI23_ho_t3)	C++20	27 / 100	2097 ms	265788 KiB

Main

#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
#include <set>

using ll = long long;
#define debug(x) #x << " = " << x << '\n'

const int INF = 1e9;
const int dx[4] = {-1, 0, +1, 0};
const int dy[4] = {0, -1, 0, +1};

int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(0);

  int n, m, k;
  std::cin >> n >> m >> k;

  int x1, y1, x2, y2;
  std::cin >> x1 >> y1 >> x2 >> y2;
  x1--, y1--, x2--, y2--;

  std::vector<std::vector<int>> a(n, std::vector<int>(m));

  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      char c;
      std::cin >> c;
      if (c == '.')  {
        a[i][j] = 0;
      } else {
        a[i][j] = 1;
      }
    }
  }

  std::vector<std::set<std::pair<int, int>>> thisDistance(n * m + 2);

  std::vector<std::vector<int>> dist(n, std::vector<int>(m, +INF));

  dist[x1][y1] = 0;

  thisDistance[0].insert({x1, y1});

  for (int d = 0; d <= n * m; d++) {
    std::set<std::pair<int, int>> st;

    auto dfs = [&](auto &&self, int x, int y) -> void {
      st.insert({x, y});
      for (int dir = 0; dir < 4; dir++) {
        int xx = x + dx[dir], yy = y + dy[dir];
        if (0 <= xx && xx < n && 0 <= yy && yy < m && dist[xx][yy] > d && !a[xx][yy]) {
          dist[xx][yy] = d;
          self(self, xx, yy);
        }
      }
    };

    for (const auto &[x, y] : thisDistance[d]) {
      if (dist[x][y] < d) {
        continue;
      }
      dfs(dfs, x, y);
      st.insert({x, y});
    }

    for (const auto &[x, y] : st) {
      for (int i = std::max(0, x - k); i <= std::min(n - 1, x + k); i++) { 
        for (int j = std::max(0, y - k); j <= std::min(m - 1, y + k); j++) {
          if (dist[i][j] == +INF && std::abs(i - x) + std::abs(j - y) < 2 * k) {
            dist[i][j] = d + 1;
            thisDistance[d + 1].insert({i, j});
          }
        }
      }
    }
  }

  std::cout << dist[x2][y2];
  
  return 0;
}

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