/// <summary>
/// Returns an enumerable collection of <see cref="TreeNode"/> objects containing the nodes
/// of the tree sorted in postfix order.
/// </summary>
/// <param name="treeEntity">The tree entity from which to get the nodes.</param>
/// <returns>An enumerable collection of <see cref="TreeNode"/> objects containing the nodes
/// of the tree sorted in prefix order.</returns>
public static IEnumerable <TreeNode> GetPostfixTree(this TreeEntityBase treeEntity)
{
if (treeEntity is null)
{
throw new ArgumentNullException(nameof(treeEntity));
}
return(TreeEntityExtensions.GetPostfixTree(treeEntity.RootNode));
}
/// <summary>
/// Returns the number of nodes contained in the tree.
/// </summary>
/// <returns>The number of nodes contained in the tree.</returns>
public static int GetSize(this TreeEntityBase treeEntity)
{
if (treeEntity is null)
{
throw new ArgumentNullException(nameof(treeEntity));
}
return(TreeEntityExtensions.GetSubtreeSize(treeEntity.RootNode));
}
/// <summary>
/// Returns an enumerable collection of <see cref="TreeNode"/> objects containing the nodes
/// of the tree sorted in postfix order.
/// </summary>
/// <param name="node"><see cref="TreeNode"/> to start at.</param>
/// <returns>An enumerable collection of <see cref="TreeNode"/> objects containing the nodes
/// of the tree sorted in prefix order.</returns>
private static IEnumerable <TreeNode> GetPostfixTree(TreeNode?node)
{
if (node != null)
{
foreach (TreeNode childNode in node.ChildNodes)
{
foreach (TreeNode subChildNode in TreeEntityExtensions.GetPostfixTree(childNode))
{
yield return(subChildNode);
}
}
yield return(node);
}
}
/// <summary>
/// Returns the number of nodes contained in the subtree of the given <paramref name="node"/>.
/// </summary>
private static int GetSubtreeSize(TreeNode?node)
{
if (node is null)
{
return(0);
}
int sum = 1; // Includes the node passed in.
for (int i = 0; i < node.ChildNodes.Count; i++)
{
sum += TreeEntityExtensions.GetSubtreeSize(node.ChildNodes[i]);
}
return(sum);
}
