Pairs | Algorithms Hackerrank Challenge | Solution in C#

 

The following is how i solved it in C#

public static int pairs(int k, List<int> arr)

    {

         int freq = 0;

        // int[] arr1 = arr.ToArray();

         arr.Sort();

         for(int i = 0; i < arr.Count()-1;i++)

         {

           for(int j = i+1; j < arr.Count();j++)

            {

               if(arr[j]-arr[i] == k){

                  freq++; 

               }              

               if(arr[j]-arr[i] > k){

                    break;

               }   

           } 

         }

         return freq;

    }

}

This challenge was marked as Medium, the author is Hackerrank.

Problem:

Given an array of integers and a target value, determine the number of pairs of array elements that have a difference equal to the target value.

Example

There are three values that differ by : , , and . Return .

Function Description

Complete the pairs function below.

pairs has the following parameter(s):

• int k: an integer, the target difference
• int arr[n]: an array of integers

Returns

• int: the number of pairs that satisfy the criterion

Input Format

The first line contains two space-separated integers  and , the size of  and the target value.
The second line contains  space-separated integers of the array .

Constraints

• each integer  will be unique

Sample Input

STDIN       Function
-----       --------
5 2         arr[] size n = 5, k =2
1 5 3 4 2   arr = [1, 5, 3, 4, 2]

Sample Output

3

Explanation

There are 3 pairs of integers in the set with a difference of 2: [5,3], [4,2] and [3,1]. .