Beautiful Triplet

Given a sequence of integers , a triplet  is beautiful if:

Given an increasing sequence of integers and the value of , count the number of beautiful triplets in the sequence.

For example, the sequence  and . There are three beautiful triplets, by index: . To test the first triplet,  and .

Description

 It must return an integer that represents the number of beautiful triplets in the sequence.

beautiful triplets has the following parameters:

• d: an integer
• arr: an array of integers, sorted ascending

Input Format

The first line contains  space-separated integers  and , the length of the sequence and the beautiful difference.
The second line contains  space-separated integers .

Output Format

Print a single line denoting the number of beautiful triplets in the sequence.

Question from hackerrank.

Solution in C# -

class Solution {

    static int beautifulTriplets(int d, int[] arr) {

         int triplets = 0;

        for(int i=0; i<arr.Length-2; i++)

        {

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

            {

                if(arr[j] - arr[i] == d)

                {

                    for(int k=j+1; k<arr.Length; k++)

                        if(arr[k] - arr[j] == d)

                            triplets++;

                }

            }

        }

        return triplets;

    }

    static void Main(string[] args) {

        TextWriter textWriter = new StreamWriter(@System.Environment.GetEnvironmentVariable("OUTPUT_PATH"), true);

        string[] nd = Console.ReadLine().Split(' ');

        int n = Convert.ToInt32(nd[0]);

        int d = Convert.ToInt32(nd[1]);

        int[] arr = Array.ConvertAll(Console.ReadLine().Split(' '), arrTemp => Convert.ToInt32(arrTemp));

        int result = beautifulTriplets(d, arr);

         textWriter.WriteLine(result);

        textWriter.Flush();

        textWriter.Close();

    }

}