結果
| 問題 | No.2222 Respawn | 
| コンテスト | |
| ユーザー |  SSRS | 
| 提出日時 | 2023-02-17 22:28:56 | 
| 言語 | C++14 (gcc 13.3.0 + boost 1.87.0) | 
| 結果 | 
                                AC
                                 
                             | 
| 実行時間 | 121 ms / 2,000 ms | 
| コード長 | 1,543 bytes | 
| コンパイル時間 | 1,512 ms | 
| コンパイル使用メモリ | 171,012 KB | 
| 実行使用メモリ | 14,848 KB | 
| 最終ジャッジ日時 | 2024-07-19 13:38:22 | 
| 合計ジャッジ時間 | 3,186 ms | 
| ジャッジサーバーID (参考情報) | judge3 / judge4 | 
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| ファイルパターン | 結果 | 
|---|---|
| sample | AC * 3 | 
| other | AC * 30 | 
ソースコード
#include <bits/stdc++.h>
using namespace std;
int main(){
  cout << fixed << setprecision(20);
  int N;
  cin >> N;
  string S;
  cin >> S;
  S += '#';
  vector<double> dp_gameover_p(N, 0);
  vector<double> dp_gameover_pe(N, 0);
  vector<double> dp_goal_p(N, 0);
  vector<double> dp_goal_pe(N, 0);
  dp_goal_p[N - 1] = 1;
  for (int i = N - 2; i >= 0; i--){
    if (S[i] == '.'){
      for (int j = i + 1; j <= i + 2; j++){
        if (S[j] == '#'){
          dp_gameover_p[i] += (double) 1 / 3;
          dp_gameover_pe[i] += (double) 1 / 3;
        } else {
          dp_gameover_p[i] += dp_gameover_p[j] / 3;
          dp_gameover_pe[i] += (dp_gameover_p[j] + dp_gameover_pe[j]) / 3;
          dp_goal_p[i] += dp_goal_p[j] / 3;
          dp_goal_pe[i] += (dp_goal_p[j] + dp_goal_pe[j]) / 3;
        }
      }
    }
  }
  vector<double> dp(N, 0);
  vector<double> dp2_p(N, 0), dp2_pe(N, 0);
  for (int i = N - 2; i >= 0; i--){
    if (S[i] == '.'){
      double gameover_p = dp_gameover_p[i] + (double) 1 / 3;
      double gameover_pe = dp_gameover_pe[i] + (double) 1 / 3;
      dp[i] += (1 / (1 - gameover_p) - 1) * (gameover_pe / gameover_p);
      dp[i] += dp_goal_pe[i] / (1 - gameover_p);
      for (int j = i + 1; j <= i + 2; j++){
        if (S[j] == '.' && j < N - 1){
          dp2_p[i] += (double) 1 / 9;
          dp2_pe[i] += (2 + dp[j]) / 9;
          dp2_p[i] += dp2_p[j] / 3;
          dp2_pe[i] += (dp2_p[j] + dp2_pe[j]) / 3;
        }
      }
      dp[i] += dp2_pe[i] / (1 - gameover_p);
    }
  }
  cout << dp[0] << endl;
}
            
            
            
        