Submission #799106

#	Time	Username	Problem	Language	Result	Execution time	Memory
799106		tch1cherin	Portals (BOI14_portals)	C++17	20 / 100	4 ms	1220 KiB

portals

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

int main() {
  int N, M;
  cin >> N >> M;
  vector<string> S(N);
  for (auto &v : S) {
    cin >> v;
  }
  vector<vector<int>> up(N, vector<int>(M, -1)), down(N, vector<int>(M, -1)), left(N, vector<int>(M, -1)), right(N, vector<int>(M, -1));
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < M; j++) {
      if (S[i][j] != '#') {
        up[i][j] = (i == 0 ? -1 : up[i - 1][j]) + 1;
        left[i][j] = (j == 0 ? -1 : left[i][j - 1]) + 1;
      }
    }
  }
  for (int i = N - 1; i >= 0; i--) {
    for (int j = M - 1; j >= 0; j--) {
      if (S[i][j] != '#') {
        down[i][j] = (i == N - 1 ? -1 : down[i + 1][j]) + 1;
        right[i][j] = (j == M - 1 ? -1 : right[i][j + 1]) + 1;
      }
    }
  }
  queue<pair<int, int>> q;
  vector<vector<int>> dist(N, vector<int>(M, INT_MAX));
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < M; j++) {
      if (S[i][j] == 'S') {
        dist[i][j] = 0;
        q.push({i, j});
      }
    }
  }
  while (!q.empty()) {
    auto [x, y] = q.front();
    q.pop();
    for (auto [i, j] : vector<pair<int, int>> {{x - 1, y}, {x, y - 1}, {x + 1, y}, {x, y + 1}, 
                                              {x - up[x][y], y}, {x, y - left[x][y]}, {x + down[x][y], y}, {x, y + right[x][y]}}) {
      if (i >= 0 && j >= 0 && i < N && j < M && S[i][j] != '#' && dist[i][j] == INT_MAX) {
        dist[i][j] = dist[x][y] + 1;
        q.push({i, j});
      }
    }
  }
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < M; j++) {
      if (S[i][j] == 'C') {
        cout << dist[i][j] << "\n";
        exit(0);
      }
    }
  }
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30