题解 | 牛牛的数学作业

import sys

def solve():
    input = sys.stdin.read().split()
    ptr = 0
    T = int(input[ptr])
    ptr += 1
    for _ in range(T):
        n = int(input[ptr])
        ptr += 1
        nums = list(map(int,input[ptr:ptr + n]))
        ptr += n


        max_num = max(nums)
        min_num = min(nums)
        range_num = max_num - min_num

        sum_num = sum(nums)
        ava_num = sum_num/n

        sum_sq = sum((x*x) for x in nums)
        vari = (sum_sq / n) - (ava_num*ava_num)

        print(f"{range_num} {vari:.3f}")

solve()