Min Max Problem HackerRank

 You will be given a list of integers, , and a single integer . You must create an array of length  from elements of  such that its unfairness is minimized. Call that array . Unfairness of an array is calculated as

Where:

- max denotes the largest integer in 

- min denotes the smallest integer in 

Example

Pick any two elements, say .

Testing for all pairs, the solution  provides the minimum unfairness.

Note: Integers in  may not be unique.

Function Description

Complete the maxMin function in the editor below.

maxMin has the following parameter(s):

int k: the number of elements to select

int arr[n]:: an array of integers

Returns

int: the minimum possible unfairness

Input Format

The first line contains an integer , the number of elements in array .

The second line contains an integer .

Each of the next  lines contains an integer  where .

Solution :// Sliding Window Approach

import java.io.*;

import java.math.*;

import java.security.*;

import java.text.*;

import java.util.*;

import java.util.concurrent.*;

import java.util.function.*;

import java.util.regex.*;

import java.util.stream.*;

import static java.util.stream.Collectors.joining;

import static java.util.stream.Collectors.toList;

class Result {

    /*

     * Complete the 'maxMin' function below.

     *

     * The function is expected to return an INTEGER.

     * The function accepts following parameters:

     *  1. INTEGER k

     *  2. INTEGER_ARRAY arr

     */

    public static int maxMin(int k, List<Integer> arr) {

    // Write your code here

Collections.sort(arr);  // Step 1: Sort the array

        int minUnfairness = Integer.MAX_VALUE;  // Initialize unfairness to a large value

        for (int i = 0; i <= arr.size() - k; i++) {

            int unfairness = arr.get(i + k - 1) - arr.get(i);  // Difference between max and min in window

            minUnfairness = Math.min(minUnfairness, unfairness);  // Update minimum unfairness

        }

        return minUnfairness;

    }

}

public class Solution {

    public static void main(String[] args) throws IOException {

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = Integer.parseInt(bufferedReader.readLine().trim());

        int k = Integer.parseInt(bufferedReader.readLine().trim());

        List<Integer> arr = IntStream.range(0, n).mapToObj(i -> {

            try {

                return bufferedReader.readLine().replaceAll("\\s+$", "");

            } catch (IOException ex) {

                throw new RuntimeException(ex);

            }

        })

            .map(String::trim)

            .map(Integer::parseInt)

            .collect(toList());

        int result = Result.maxMin(k, arr);

        bufferedWriter.write(String.valueOf(result));

        bufferedWriter.newLine();

        bufferedReader.close();

        bufferedWriter.close();

    }

}