题解 | 牛牛的数学作业

import sys

nn = int(input())
for ii in range(nn):
    n = int(input())
    score = []
    score = input().split()
    for i in range(n):
        score[i] = int(score[i])
    min = score[0]
    max = score[0]
    total = score[0]
    for i in range(1,n):
        score_i = score[i] #避免频繁调动
        if score_i < min:
            min = score_i
        if  score_i > max:
            max = score_i
        total += score_i
    print(max-min,end=" ")
    average = total / n
    var = 0
    for i in range(n):
        var += ((average-score[i])**2)
    var = var / n
    print(format(var,'.3f'))