Java 代码

import java.util.Scanner;

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

        String s = cin.next();

        cin.nextLine();
        double sum = 0.0;
        int count = 0;

        for (int i = 0; i < 12; i ++ )
        {
            for (int j = 0; j <= i; j ++)
                cin.nextDouble();

            for (int j = i + 1; j < 12; j++)
            {
                sum += cin.nextDouble();
                count += 1;
            }
        }

        if (s.compareTo("S") == 0 )
            System.out.println (String.format("%.1f", sum));
        if (s.compareTo("M") == 0)
            System.out.println (String.format("%.1f", sum/count));
    }
}