题解 | 牛牛的数学作业

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int sj= in.nextInt();
        for (int i = 0; i < sj; i++) {
            int mfsjl= in.nextInt();
            int[] shuju=new int[mfsjl];
            int sum=0;
            int max=Integer.MIN_VALUE;
            int min=Integer.MAX_VALUE;
            for (int i1 = 0; i1 < mfsjl; i1++) {
                shuju[i1]= in.nextInt();
                sum+=shuju[i1];
                if (shuju[i1]>max){
                    max=shuju[i1];
                }
                if (shuju[i1]<min){
                    min=shuju[i1];
                }
            }
            int jc = max - min;
            double pjs =(double) sum / mfsjl;
            double f_c=0;
            for (int i2 : shuju) {
                f_c+=Math.pow(i2-pjs,2);
            }
            double fc=f_c/mfsjl;
            System.out.printf("%d %.3f",jc,fc);
            System.out.println();
        }
        
    }
}