[Programmers] 42889. 실패율

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

class Solution {
  public int[] solution(int N, int[] lastStages) {
    int nPlayers = lastStages.length;
    int[] nStagePlayers = new int[N + 2];
    for (int stage : lastStages) {
      nStagePlayers[stage] += 1;
    }

    int remainingPlayers = nPlayers;
    List<Stage> stages = new ArrayList<>();
    for (int id = 1 ; id <= N; id++) {
      double failure = (double) nStagePlayers[id] / remainingPlayers;
      remainingPlayers -= nStagePlayers[id];

      Stage s = new Stage(id, failure);
      stages.add(s);
    }
    Collections.sort(stages, Collections.reverseOrder());

    int[] answer = new int[N];
    for (int i = 0; i < N; i++) {
      answer[i] = stages.get(i).id;
    }
    return answer;
  }

  class Stage implements Comparable<Stage> {
    public int id;
    public double failure;

    public Stage(int id_, double failure_) {
      id = id_;
      failure = failure_;
    }

    @Override
    public int compareTo(Stage o) {
      if (failure < o.failure ) {
        return -1;
      }
      if (failure > o.failure ) {
        return 1;
      }
      return 0;
    }
  }
}