C# MaxHeap<T> where T: IComparable<T> Implementation

CSharpMaxHeapGeneric

public class MaxHeap<T> where T: System.IComparable<T> 
{
    public List<T> heapList {get; set;}

    public int Count {get => heapList.Count;}

    private int GetLeftChildIndex(int elementIndex) => 2 * elementIndex + 1;
    private int GetRightChildIndex(int elementIndex) => 2 * elementIndex + 2;
    private int GetParentIndex(int elementIndex) => (elementIndex - 1) / 2;

    private bool HasLeftChild(int elementIndex) => GetLeftChildIndex(elementIndex) < Count;
    private bool HasRightChild(int elementIndex) => GetRightChildIndex(elementIndex) < Count;
    private bool IsRoot(int elementIndex) => elementIndex == 0;

    private T GetLeftChild(int elementIndex) => heapList[GetLeftChildIndex(elementIndex)];
    private T GetRightChild(int elementIndex) => heapList[GetRightChildIndex(elementIndex)];
    private T GetParent(int elementIndex) => heapList[GetParentIndex(elementIndex)];

    public MaxHeap()
    {
        heapList = new List<T>();
    }

    public void PrintHeap()
    {
        foreach (T item in heapList)
        {
            Console.WriteLine(item.ToString());
        }
    }

    public void Push (T item)
    {
        heapList.Add(item);
        BubbleUp(Count - 1);
    }

    public T Pop ()
    {

        if (Count == 0)
        {
           throw new IndexOutOfRangeException();
        }

        // store copy to return at the end of the method
        T firstItemCopy = heapList[0];

        // move last item to first position
        heapList[0] = heapList[Count - 1];

        // remove the last thing off the list because it's redundant (it's now at the top of the heap)
        heapList.RemoveAt(Count - 1);

        FilterDown(0);

        return firstItemCopy;
    }

    public T Peek()
    {
        if (Count == 0)
        {
           throw new IndexOutOfRangeException();
        }

        return heapList[0];
    }

    public bool IsEmpty()
    {
        return Count == 0;
    }

    void Swap (int firstIndex, int secondIndex)
    {
        T temp = heapList[firstIndex];
        heapList[firstIndex] = heapList[secondIndex];
        heapList[secondIndex] = temp;
    }

    void BubbleUp (int index)
    {
        while (!IsRoot(index) && heapList[index].CompareTo(GetParent(index)) > 0)
        {
            int parentIndex = GetParentIndex(index);

            Swap(parentIndex, index);

            index = parentIndex;
        }
    }

    void FilterDown (int index)
    {
        // set currentIndex
        int currentIndex = index;

        // while loop: check if index has a left child
        while (HasLeftChild(currentIndex))
        {
            // if it does, establish a bigger index
            int biggerIndex = GetLeftChildIndex(currentIndex);

            // check and see which of the left or right child has a bigger value
            // allocate the bigger value child as the bigger index
            if (HasRightChild(currentIndex) && GetRightChild(currentIndex).CompareTo(GetLeftChild(currentIndex)) > 0)
            {
                biggerIndex = GetRightChildIndex(currentIndex);
            }

            // if the element at biggerIndex is smaller than the element at currentIndex, then break
            if (heapList[biggerIndex].CompareTo(heapList[currentIndex]) <= 0)
            {
                break;
            }

            // otherwise, swap element[currentIndex] with element[biggerIndex]
            Swap(biggerIndex, currentIndex);

            // set index to biggerIndex
            currentIndex = biggerIndex;

            // while loop will break when the index no longer has a left child
        }
    }
}