algoritmos - Lista4 - questao A

import java.util.Scanner;
import java.lang.Math;

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/**
 *
 */
public class Main {

    public static int[] quicksort(int[] array, int inicio, int fim) {
        if (inicio < fim) {
            int pivot = partition(array, inicio, fim);
            quicksort(array, inicio, pivot - 1);
            quicksort(array, pivot + 1, fim);
        }
        return array;
    }

    public static int partition(int[] a, int lo, int hi) {
        int pivot = a[hi];
        int i = lo - 1;
        for (int j = lo; j <= hi - 1; j++) {
            if (a[j] <= pivot) {
                i += 1;
                swap(a, i, j);
            }
        }
        swap(a, i + 1, hi);
        return i + 1;
    }

    public static void swap(int[] array, int i, int j) {
        int temp = array[i];
        array[i] = array[j];
        array[j] = temp;
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int test_cases = input.nextInt();
        int[] casas;
        int test_complete = 0;
        int array_size;
        while (test_complete < test_cases) {
            array_size = input.nextInt();
            casas = new int[array_size];

            for (int i = 0; i < casas.length; i++) {
                casas[i] = input.nextInt();
            }

            quicksort(casas, 0, casas.length - 1);
            int middle_home = 0;
            if (casas.length % 2 == 0) {
                middle_home = (casas.length / 2) - 1;

            }
            if (casas.length % 2 == 1) {
                middle_home = (int) Math.floor((casas.length / 2));
            }
            int distance = 0;
            int position = casas.length - 1;
            while (position > middle_home) {
                distance += (casas[position] - casas[middle_home]);
                position--;
                //System.out.println("distance: " + distance);
            }
            position = 0;
            while (position < middle_home) {
                distance += (casas[middle_home] - casas[position]);
                position++;
                //System.out.println("distance:" + distance);
            }
            for (int i = 0; i < casas.length; i++) {
                //System.out.println(casas[i] + " ");
            }
            System.out.println(distance);
            test_complete++;
        }
    }
}