Lily's Homework HackerRank

LilyHomework.java

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 'lilysHomework' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts INTEGER_ARRAY arr as parameter.
     */
    
    
    public static int lilysHomework(List<Integer> arr) {
    
        int swapCount = 0;
        int reverseSwapCount = 0;
        
        int n = arr.size();
        
        int[] hw = new int[n];
        int[] hw2 = new int[n];   
        
        Integer[] hwAscSort = new Integer[n];
        Integer[] hwDescSort = new Integer[n];
        
        Map<Integer,Integer> original = new HashMap<>();
        Map<Integer,Integer> original2 = new HashMap<>();
        
        //Initialization of variables
        for(int i = 0; i < n; i++)
        {
            int current = arr.get(i);
            hwAscSort[i] = current;
            hwDescSort[i] = current;
            hw[i] = current;
            hw2[i] = current;
            original.put(current,i);
            original2.put(current,i);
        }
            
        Arrays.sort(hwAscSort);  //ascending sort
        Arrays.sort(hwDescSort, Collections.reverseOrder());  //descending sort
        
        //swap the elements from homework to the correct position
        for(int i = 0; i < n; i++)
        {
            if(hw[i] != hwAscSort[i])
            {
                int tmp = hw[i];
                hw[i] = hw[original.get(hwAscSort[i])];
                hw[original.get(hwAscSort[i])] = tmp;
                original.put(tmp,original.get(hwAscSort[i]));
                swapCount++;               
            }
        }
        
        //swap the elements from homework to the correct position
        for(int i = 0; i < n; i++)
        {
            if(hw2[i] != hwDescSort[i])
            {
                int tmp = hw2[i];
                hw2[i] = hw2[original.get(hwDescSort[i])];
                hw2[original2.get(hwDescSort[i])] = tmp;
                original2.put(tmp, original2.get(hwDescSort[i]));
                reverseSwapCount++;
            }
        }
        return Math.min(swapCount,reverseSwapCount);
    }

}

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());

        List<Integer> arr = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
            .map(Integer::parseInt)
            .collect(toList());

        int result = Result.lilysHomework(arr);

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

        bufferedReader.close();
        bufferedWriter.close();
    }
}