Distinct Pair Sums

Given an array of integers and a target integer \( k \), your task is to determine the number of unique pairs in the array whose sum is exactly \( k \). A pair \((a, b)\) is considered the same as \((b, a)\) and should only be counted once even if there are multiple occurrences in the array.

Note: The pair must consist of two distinct elements from the array. If no valid pairs exist, the answer should be 0.

inputFormat

The input begins with an integer \( T \) denoting the number of test cases. Each test case is described as follows:

• The first line contains two space-separated integers \( n \) and \( k \), where \( n \) is the number of elements in the array and \( k \) is the target sum.
• The second line contains \( n \) space-separated integers representing the elements of the array.

All input is read from standard input (stdin).

outputFormat

For each test case, print a single line with one integer representing the count of unique pairs in the array that add up to \( k \). All output should be written to standard output (stdout).

## sample

1
5 10
4 3 5 7 8

1

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