private static TreeNode AddToTree(int[] array, int start, int end)
{
if (end < start)
{
return null;
}
var mid = (start + end) / 2;
var node = new TreeNode(array[mid]);
node.SetLeftChild(AddToTree(array, start, mid - 1));
node.SetRightChild(AddToTree(array, mid + 1, end));
return node;
}
