public class HeapSort
{
    private readonly List<int> _heapList;
    private readonly int _heapsize;

    public HeapSort(List<int> heapList, int heapsize)
    {
        this._heapsize = heapsize;
        this._heapList = heapList;
    }

    private void Heapify(int i, int n)
    {
        var iPosition = _heapList[i];
        var iChange = 2 * i;
        while (iChange <= n)
        {
            if (iChange < n && _heapList[iChange] < _heapList[iChange + 1])
            {
                iChange++;
            }
            if (iPosition >= _heapList[iChange])
            {
                break;
            }
            _heapList[iChange / 2] = _heapList[iChange];
            iChange *= 2;
        }
        _heapList[iChange / 2] = iPosition;
    }

    public void Sort()
    {
        for (var i = _heapsize / 2; i >= 0; i--)
        {
            Heapify(i, _heapsize - 1);
        }

        for (var i = _heapsize - 2; i >= 0; i--)
        {
            var iValue = _heapList[i + 1];
            _heapList[i + 1] = _heapList[0];
            _heapList[0] = iValue;
            Heapify(0, i);
        }
    }

    public string PrintList()
    {
        var myValue = "";
        for (int i = 0; i < _heapsize; i++)
        {
            myValue += _heapList[i] + " ";
        }
        return myValue;
    }
}