ACM ICPC is approaching and we urge you to participate in it. Try to solve the given problem.
Given an array A with N elements, find the number of pairs, (A[i], A[j]) where i < j, whose absolute difference is K and sum is divisible by K.
Input Format
The first line contains the number of test cases, T.
Each test case is as follows:
The first line contains two space seperated integers, N (the number of elements in the array A) and K.
Second line has N space seperated numbers, Ai.
Output Format
For each testcase, print a single line containing the number of distinct pairs satisfying the given criteria.
Constraints
1 <= T <= 10
2 <= N <= 105
1 <= K <= 109
1 <= Ai <= 109, where i ∈ [0,n)
Pair 1 : (1,3) - |1-3| = 2 & (1+3) is divisible by 2.
Pair 2 : (3,5) - |3-5| = 2 & (3+5) is divisible by 2.
Pair 3 : (5,7) - |5-7| = 2 & (5+7) is divisible by 2.
