MaxHeap.cs

private void ReCalculateDown()
{
    int index = 0;
    while (HasLeftChild(index))
    {
        var biggerIndex = GetLeftChildIndex(index);
        if (HasRightChild(index) && GetRightChild(index) > GetLeftChild(index))
        {
            biggerIndex = GetRightChildIndex(index);
        }

        if (_elements[biggerIndex] < _elements[index])
        {
            break;
        }

        Swap(biggerIndex, index);
        index = biggerIndex;
    }
}

private void ReCalculateUp()
{
    var index = _size - 1;
    while (!IsRoot(index) && _elements[index] > GetParent(index))
    {
        var parentIndex = GetParentIndex(index);
        Swap(parentIndex, index);
        index = parentIndex;
    }
}