結果

問題 No.1323 うしらずSwap
ユーザー ei1333333
提出日時 2020-12-07 23:45:17
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 180 ms / 3,000 ms
コード長 4,236 bytes
コンパイル時間 2,490 ms
コンパイル使用メモリ 209,456 KB
最終ジャッジ日時 2025-01-16 19:09:15
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
（要ログイン）
ファイルパターン 結果
sample AC * 3
other AC * 59
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
using namespace std;
using pi = pair< int, int >;
constexpr int inf = 1 << 30;
constexpr int vy[] = {-1, 1, 0, 0};
constexpr int vx[] = {0, 0, -1, 1};
template< typename T, typename E >
bool chmin(T &a, E b) {
  if(a > b) {
    a = b;
    return true;
  } else {
    return false;
  }
}
int main() {
  int H, W, Ya, Xa, Yb, Xb;
  cin >> H >> W >> Ya >> Xa >> Yb >> Xb;
  --Ya, --Xa, --Yb, --Xb;
  vector< string > S(H);
  for(auto &s : S) cin >> s;
  vector< vector< int > > min_cost(H, vector< int >(W, inf));
  vector< vector< int > > ways(H, vector< int >(W, 0));
  vector< vector< int > > from(H, vector< int >(W, -1));
  {
    queue< pi > que;
    min_cost[Ya][Xa] = 0;
    ways[Ya][Xa] = 1;
    que.emplace(Ya, Xa);
    while(!que.empty()) {
      auto[y, x] = que.front();
      que.pop();
      for(int k = 0; k < 4; k++) {
        int ny = y + vy[k];
        int nx = x + vx[k];
        if(S[ny][nx] == '#') continue;
        if(chmin(min_cost[ny][nx], min_cost[y][x] + 1)) {
          from[ny][nx] = k;
          ways[ny][nx] = 0;
          que.emplace(ny, nx);
        }
        if(min_cost[y][x] + 1 == min_cost[ny][nx]) {
          ways[ny][nx] += ways[y][x];
          chmin(ways[ny][nx], 2);
        }
      }
    }
  }
  if(ways[Yb][Xb] == 0) {
    cout << -1 << "\n";
    return 0;
  }
  if(ways[Yb][Xb] >= 2) {
    cout << min_cost[Yb][Xb] * 2 << "\n";
    return 0;
  }
  vector< pair< int, int > > path;
  int cy = Yb, cx = Xb;
  path.emplace_back(cy, cx);
  while(cy != Ya || cx != Xa) {
    int py = cy + vy[from[cy][cx] ^ 1];
    int px = cx + vx[from[cy][cx] ^ 1];
    cy = py;
    cx = px;
    path.emplace_back(cy, cx);
  }
  assert(min_cost[Yb][Xb] + 1 == path.size());
  for(auto &p : path) S[p.first][p.second] = '*';
  for(int i = 1; i + 1 < path.size(); i++) {
    for(int j = 0; j < 4; j++) {
      int ny = path[i].first + vy[j];
      int nx = path[i].second + vx[j];
      if(S[ny][nx] == '.') {
        cout << min_cost[Yb][Xb] * 2 + 2 << "\n";
        return 0;
      }
    }
  }
  int ret = inf;
  int pre = min_cost[Yb][Xb];
  {
    {
      queue< pi > que;
      min_cost[Yb][Xb] = 0;
      que.emplace(Yb, Xb);
      while(!que.empty()) {
        auto[y, x] = que.front();
        que.pop();
        for(int k = 0; k < 4; k++) {
          int ny = y + vy[k];
          int nx = x + vx[k];
          if(S[ny][nx] == '#') continue;
          if(chmin(min_cost[ny][nx], min_cost[y][x] + 1)) {
            que.emplace(ny, nx);
          }
        }
      }
    }
    for(int i = 1; i + 1 < H; i++) {
      for(int j = 1; j + 1 < W; j++) {
        if(S[i][j] == '.') {
          int deg = 0;
          for(int k = 0; k < 4; k++) {
            int ny = i + vy[k];
            int nx = j + vx[k];
            if(S[ny][nx] != '#') {
              ++deg;
            }
          }
          if(deg >= 3 && min_cost[i][j] != inf) {
            chmin(ret, min_cost[i][j] * 4 + 4 + pre * 2);
          }
        }
      }
    }
    {
      int deg = 0;
      for(int k = 0; k < 4; k++) {
        int ny = Ya + vy[k];
        int nx = Xa + vx[k];
        if(S[ny][nx] == '.') {
          ++deg;
        }
      }
      if(deg >= 2) {
        chmin(ret, 4 + pre * 2);
      }
    }
    {
      int deg = 0;
      for(int k = 0; k < 4; k++) {
        int ny = Yb + vy[k];
        int nx = Xb + vx[k];
        if(S[ny][nx] == '.') {
          ++deg;
        }
      }
      if(deg >= 2) {
        chmin(ret, 4 + pre * 2);
      }
    }
  }
  {
    vector< vector< int > > min_cost2(H, vector< int >(W, inf));
    queue< pi > que;
    min_cost2[Ya][Xa] = 0;
    que.emplace(Ya, Xa);
    S[Ya][Xa] = '.';
    S[Yb][Xb] = '.';
    while(!que.empty()) {
      auto[y, x] = que.front();
      que.pop();
      for(int k = 0; k < 4; k++) {
        int ny = y + vy[k];
        int nx = x + vx[k];
        if(S[ny][nx] == '#' || S[ny][nx] == '*') continue;
        if(y == Ya && x == Xa && ny == Yb && nx == Xb) continue;
        if(chmin(min_cost2[ny][nx], min_cost2[y][x] + 1)) {
          que.emplace(ny, nx);
        }
      }
    }
    if(min_cost2[Yb][Xb] != inf) {
      chmin(ret, pre + min_cost2[Yb][Xb]);
    }
  }
  if(ret >= inf) ret = -1;
  cout << ret << "\n";
}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0