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.
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.
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.
Example(To be used only for expected output) :
5 2 9 6
1 2 3 Output
Note:The Input/Ouput format and Example given are used for system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console. The task is to complete the function specified, and not to write the full code.