pairs

John has $n$ points on the X axis, and their coordinates are $(x[i],0),(i=0,1,2,…,n-1)$. He wants to know how many pairs$<a,b>$ that $|x[b]-x[a]| \leq k. (a<b)$

The first line contains a single integer $T$ (about 5), indicating the number of cases.
Each test case begins with two integers $n,k (1 \leq n \leq 100000,1 \leq k \leq {10}^{9})$.
Next $n$ lines contain an integer $x[i] ({-10}^{9} \leq x[i] \leq {10}^{9})$, means the X coordinates.

For each case, output an integer means how many pairs$<a,b>$ that $|x[b]-x[a]| \leq k$.

2
5 5
-100
0
100
101
102
5 300
-100
0
100
101
102

3
10

BestCoder Round #31