题目描述
JJ loves playing with averages. He has an array A of length N. He wants to divide the array A into two non-empty subsets P and Q such that the value of mean(P) + mean(Q) is as large as possible. (Note that each A_{i} must belong to either subset P or subset Q).
Help him find this maximum value of mean(P) + mean(Q).
As a reminder, the mean of a subset X of size M is defined as: $mean(X) = \dfrac{\sum_{i = 1}^{M} X_{i}}{M}$.
For example$, mean([3, 1, 4, 5]) = \frac{3 + 1 + 4 + 5}{4} = 3.25$.
------ Input Format ------
- The first line contains T - the number of test cases. Then the test cases follow.
- The first line of each test case contains an integer N - the size of the array A.
- The second line of each test case contains $N space-separated integers A_{1}, A_{2}, \dots, A_{N}$ denoting the array A.
------ Output Format ------
Output the largest value of mean(P) + mean(Q).
Your answer is considered correct if its absolute or relative error does not exceed 10^{-6}.
Formally, let your answer be a, and the jury's answer be b. Your answer is accepted if and only if $\frac{|a - b|}{\max{(1, |b|)}}$ ≤ 10^{-6}.
------ Constraints ------
$1 ≤ T ≤ 100$
$2 ≤ N ≤ 1000$
$1 ≤ A_{i} ≤ 10^{6}$
----- Sample Input 1 ------
2
2
4 5
5
2 2 2 2 2
----- Sample Output 1 ------
9.000000
4.000000
----- explanation 1 ------
Test case-1: We can divide the two elements into two non-empty subsets $P$ and $Q$ as follows: $P = [4]$, $Q = [5]$.
Therefore, $mean(P) + mean(Q) = 9$.
Test case-2: In whatever way we divide the elements of the array, mean of both the subsets will always be $2$.
Therefore, $mean(P) + mean(Q) = 4$.
输入格式
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输出格式
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