Question

I need to sort arrays of varying sizes. These sizes are: 10 elements, 50 elements, 100 elements, 500 elements, and 1000 elements. For each of these array sizes, I should use one array that is already sorted, another array that is partially sorted, and one that is random. I should use three sorts, like quicksort, insertion, or bubblesort. I have been working this for 2 weeks but can not seem to create an call the arrays.

Answer 1

Here are some utility methods to create test arrays and to verify if your sorting method is working fine:

public static Integer[] createRandomArray(int size) {
    Integer[] result = new Integer[size];
    Random randomGenerator = new Random();
    for(int i = 0; i < size; i++) {
        result[i] = randomGenerator.nextInt(size*100);
    }
    return result;
}

public static Integer[] createSortedArray(int size) {
    return createPartiallySortedArray(size, 0, size);
}

public static Integer[] createPartiallySortedArray(int size, int from, int to) {
    Integer[] result = createRandomArray(size);
    Arrays.sort(result, from, to);
    return result;
}

public static boolean isSorted(Integer[] original, Integer[] sorted) {
    Integer[] clonedOriginal = Arrays.copyOf(original, original.length);
    Arrays.sort(clonedOriginal);
    return Arrays.equals(clonedOriginal, sorted);
}

Note – the from and to parameters have to be in the range [0..size-1] with from < to.

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Here’s fragment that you can use to create your arrays, feed them into your sorter and verify the results:

public static void main(String[] args) {
    List<Integer[]> arrays = new ArrayList<Integer[]>();
    int size = 100;
    arrays.add(createRandomArray(size));
    arrays.add(createPartiallySortedArray(size, 0, size/2));
    arrays.add(createSortedArray(size));

    List<Integer[]> result = doBubbleSort(arrays);  // <- implement that method
    for (int i = 0; i < arrays.size(); i++)
        System.out.println(isSorted(arrays.get(i), result.get(i)));
}