[Java] 백준 25206 : 너의 평점은 / 코드 O

import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws IOException {
        Map<String, Double> avgScores = new HashMap<>();
        String[] levels = {"A+", "A0", "B+", "B0", "C+", "C0", "D+", "D0"};
        for (int i = 0; i < levels.length; i ++) {
            avgScores.put(levels[i], 4.5 - (0.5 * i));
        }
        avgScores.put("F", 0.0);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        double sumScore = 0;
        double sumVolume = 0;
        for (int i = 0; i < 20; i ++) {
            StringTokenizer st = new StringTokenizer(br.readLine());
            st.nextToken();
            double volume = Double.parseDouble(st.nextToken());
            String level = st.nextToken();
            if (level.equals("P")) {
                continue;
            }
            double score = avgScores.get(level);
            sumScore += volume * score;
            sumVolume += volume;
        }
        System.out.print(sumScore / sumVolume);
    }
}