/// <summary>
/// Traverses a tree
/// </summary>
/// <typeparam name="T">Tree data type</typeparam>
/// <param name="root">Root node of tree</param>
/// <param name="order">Traversal order</param>
/// <returns>An enumeration of the nodes in the specified traverse order</returns>
public static IEnumerable <Tree <T> > Traverse <T>(this Tree <T> root, TreeTraversalOrder order = TreeTraversalOrder.BreadthFirst)
{
if (order == TreeTraversalOrder.BreadthFirst)
{
return(TraverseBF(root));
}
else
{
return(TraverseDF(root, order));
}
}
/// <summary>
/// Applies an action to every node of the tree
/// </summary>
/// <typeparam name="T">Tree data type</typeparam>
/// <param name="root">Root node of tree</param>
/// <param name="action">Action to apply</param>
/// <param name="order">Traversal order</param>
public static void Apply <T>(this Tree <T> root, Action <Tree <T> > action, TreeTraversalOrder order = TreeTraversalOrder.BreadthFirst)
{
// Safety check
if (action == null)
{
return;
}
// Apply action
foreach (var node in Traverse(root, order))
{
action(node);
}
}
public IEnumerable <T> GetEnumerable(TreeTraversalOrder order)
{
switch (order)
{
case TreeTraversalOrder.InOrder:
return(InOrderTraversal());
case TreeTraversalOrder.PostOrder:
return(PostOrderTraversal());
case TreeTraversalOrder.PreOrder:
return(PreOrderTraversal());
}
return(null);
}
public IEnumerable <T> Traverse(TreeTraversalOrder order)
{
if (this.root == null)
{
return(Enumerable.Empty <T>());
}
switch (order)
{
case TreeTraversalOrder.PreOrder: return(TraversePreOrder(root));
case TreeTraversalOrder.InOrder: return(TraverseInOrder(root));
case TreeTraversalOrder.PostOrder: return(TraversePostOrder(root));
case TreeTraversalOrder.LevelOrder: return(TraverseLevelOrder(root));
default:
throw new NotImplementedException();
}
}
private static IEnumerable <Tree <T> > TraverseDF <T>(this Tree <T> root, TreeTraversalOrder order)
{
// Preorder - return root first
if (order == TreeTraversalOrder.DepthFirstPreOrder)
{
yield return(root);
}
// Return children
foreach (var child in root.Children)
{
foreach (var node in TraverseDF(child, order))
{
yield return(node);
}
}
// Postorder - return root last
if (order == TreeTraversalOrder.DepthFirstPostOrder)
{
yield return(root);
}
}