Java 代码

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner cin = new Scanner(System.in);

        int n = cin.nextInt();

        String s = cin.next();

        for (int i = 0; i < 12; i ++)
        {
            String m = cin.nextLine();
            if (i == n)
            {
                double sum = 0;
                for (int j = 0; j < 12; j ++)
                {
                    sum += Double.valueOf(cin.next());
                }
                if (s.compareTo("S") == 0)
                    System.out.println (String.format("%.1f", sum));
                else if (s.compareTo("M") == 0)
                    System.out.println (String.format("%.1f", sum / 12.0));

                break;
            }
        }
    }
}