**Compilation/Execution Result:**

Given an array S consisting of n numbers, find the sum of difference between last and first element of each subset.

For example for set 5,8 there are 3 subsets possible

5 (difference is 5-5 = 0 as 5 is the only last and first element)

8 (difference is 8-8 = 0 as 8 is the only last and first element)

5 8 (difference is 8-5 = 3 as 8 is the last element and 5 is the first element)

thus difference sum is 0+0+3 = 3

You are required to complete the function which returns an integer denoting the sum of difference between last and first element for each subset of array S.

Note: Elements in the subset should be in the same order as in the set S.

**Input:**

The first line of input contains an integer T denoting the no of test cases. Then T test cases follow. Each test case contains 2 lines the first line of input contains an integer N denoting the size of the array A. In the next line are N space separated values of the array A.

**Output:**

For each test case in a new line output will be the sum of difference between last and first element of each subset of array S.

**Constraints:**

1<=T<=100

1<=N<=20

1<=A[]<=1000

**Example(To be used only for expected output) :
Input:**

2

4

5 2 9 6

3

1 2 3

21

6

Author: Shubham Joshi 1

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