BiDirectional Bubble Sort

Cocktail sort, also known as bidirectional bubble sort, cocktail shaker sort, shaker sort (which can also refer to a variant of selection sort), ripple sort, shuttle sort or happy hour sort, is a variation of bubble sort that is both a stable sorting algorithm and a comparison sort. The algorithm differs from bubble sort in that it sorts in both directions on each pass through the list. This sorting algorithm is only marginally more difficult to implement than bubble sort, and solves the problem with so-called turtles in bubble sort.

The first rightward pass will shift the largest element to its correct place at the end, and the following leftward pass will shift the smallest element to its correct place at the beginning. The second complete pass will shift the second largest and second smallest elements to their correct places, and so on. After i passes, the first i and the last i elements in the list are in their correct positions, and do not need to be checked. By shortening the part of the list that is sorted each time, the number of operations can be halved.

public IList BiDerectionalBubleSort(IList arrayToSort)
{

    int limit = arrayToSort.Count;
    int st = -1;
    bool swapped = false;
    do
    {
        swapped = false;
        st++;
        limit--;

        for (int j = st; j < limit; j++)
        {
            if (((IComparable)arrayToSort[j]).CompareTo(arrayToSort[j + 1]) > 0)
            {
                object temp = arrayToSort[j];
                arrayToSort[j] = arrayToSort[j + 1];
                arrayToSort[j + 1] = temp;
                swapped = true;
                RedrawItem(j);
                RedrawItem(j + 1);
                pnlSamples.Refresh();
                if (chkCreateAnimation.Checked)
                    SavePicture();

            }
        }
        for (int j = limit - 1; j >= st; j--)
        {
            if (((IComparable)arrayToSort[j]).CompareTo(arrayToSort[j + 1]) > 0)
            {
                object temp = arrayToSort[j];
                arrayToSort[j] = arrayToSort[j + 1];
                arrayToSort[j + 1] = temp;
                swapped = true;
                RedrawItem(j);
                RedrawItem(j + 1);

                pnlSamples.Refresh();
                if (chkCreateAnimation.Checked)
                    SavePicture();

            }
        }

    } while (st < limit && swapped);

    return arrayToSort;
}