 Sum of f(a[i], a[j]) over all pairs in an array of n integers
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Given an array A of n integers, find the sum of f(a[i], a[j]) of all pairs (i, j) such that (1 <= i < j <= n).
f(a[i], a[j]):       If | a[j]-a[i] | > 1

f(a[i], a[j]) = a[j] - a[i]

Else  if | a[j]-a[i] | <= 1

f(a[i], a[j]) = 0

Input:
The first line of the input contains T denoting the number of test cases. For each test case, the first line contains integer denoting the size of the array A, followed by n space separated integers denoting the element of array A.

Output:
For each test case, the output is an integer denoting the sum
of f(a[i],a[j]) of all pairs.

Constraints:
1<=T<=100
1<=n<=50

Example:
Input:

2
4
6 6 4 4
5
1 2 3 1 3
Output:
-8
4

Explanation:
1.
All pairs are: (6 - 6) + (4 - 6) + (4 - 6) + (4 - 6) + (4 - 6) + (4 - 4) = -8
2. The pairs that add up are: (3, 1), (3, 1) to give 4, rest all pairs according to condition gives 0.

#### ** For More Input/Output Examples Use 'Expected Output' option **

Contributor: Vanshika
Author: Vanshika_pec

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