HDU 5178 pairs（二分 STL lower_bound）

pairs

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2038    Accepted Submission(s): 733

Problem Description

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]|≤k.(a<b)

 

Input

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≤n≤100000,1≤k≤109).
Next  n lines contain an integer  x[i](−109≤x[i]≤109), means the X coordinates.

Output

For each case, output an integer means how many pairs <a,b> that  |x[b]−x[a]|≤k.

Sample Input

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

Sample Output

3 10

 

#include 
#include
#include
using namespace std;
int a[1000];
int cmp(int a,int b)
{
	return  a