Reena had been given an array arr[] of positive integers of size N.Help her to find the value A.
A = arr[n]*arr[n] - arr[n-1]*arr[n-1] + arr[n-2]*arr[n-2] - ......... upto index 1
Input:
1. The first line of the input contains a single integer T denoting the number of test cases. The description of T test cases follows.
2. The first line of each test case contains a single integer N.
3. The second line containsN space-separated positive integers represents array arr.
Output: For each test case, print the value of A in a single line
Constraints:
1. 1 <= T <= 10 2. 1 <= N <= 100000
3. 1 <= arr[i] <= 100
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Avoid using static/global variables in coding problems as your code is tested
against multiple test cases and these tend to retain their previous values.
Passing the Sample/Custom Test cases in coding problems does not guarantee the
correctness of code. On submission, your code is tested against multiple test cases
consisting of all possible corner cases and stress constraints.
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