ArrayBinaryTree.cs

using System;

namespace AlgorithmsAndDataStructures.DataStructures.BinaryTrees;

public class ArrayBinaryTree<T>
{
    private T[] tree;

    public ArrayBinaryTree(int initialCapacity = 8)
    {
        tree = new T[initialCapacity + 1];
    }

    public void Root(T value)
    {
        tree[1] = value;
    }

    public void SetLeft(T parent, T value)
    {
        for (var i = 0; i < tree.Length; i++)
        {
#pragma warning disable HAA0601 // Value type to reference type conversion causing boxing allocation
            if (tree[i].Equals(parent))
#pragma warning restore HAA0601 // Value type to reference type conversion causing boxing allocation
            {
                var leftIndex = i * 2;

                if (leftIndex >= tree.Length) ExpandTree();

                tree[leftIndex] = value;
            }
        }
    }

    public void SetRight(T parent, T value)
    {
        for (var i = 0; i < tree.Length; i++)
        {
#pragma warning disable HAA0601 // Value type to reference type conversion causing boxing allocation
            if (tree[i].Equals(parent))
#pragma warning restore HAA0601 // Value type to reference type conversion causing boxing allocation
            {
                var rightIndex = i * 2 + 1;

                if (rightIndex >= tree.Length) ExpandTree();

                tree[rightIndex] = value;
            }
        }
    }

    private void ExpandTree()
    {
        var expandedTree = new T[tree.Length * 2];

        Array.Copy(tree, 0, expandedTree, 0, tree.Length);

        tree = expandedTree;
    }

    public T[] GetTree()
    {
        return tree;
    }
}