Count Pairs of Numbers with a Given Difference K

Given an unsorted array and a number n, find if there exists a pair of elements in the array whose difference is n. Return count of such pairs.

Example k=4 and a[]={7,623,19,10,11,9,3,15}

Output should be : 6

Pairs can be:

7,11(11-7=4)

7,3(7-3=4)

6,10(10-6=4)

19,23(23-19=4)

15,19(19-15=4)

15,11(15-11=4)

 

Please Help me.

 

Thanks & Regards
Ashish Kumar Sahu