Recursion with yield return elements order in tree
You need to explicitly iterate + yield return the nodes of children of each node ala:
public IEnumerable<int> preOrder(Node root)
{
if (root == null)
yield break;
yield return root.val;
if (root.left != null)
foreach (int i in preOrder(root.left))
yield return i;
if (root.right != null)
foreach (int i in preOrder(root.right))
yield return i;
}
Have you tried something like:
private IEnumerable<Node> getAllNodesRecursively(Node subnode)
{
// Return the parent before its children
yield return subnode;
foreach (Node node in subnode.Nodes)
{
foreach(Node n in getAllNodesRecursively(node))
{
yield return n;
}
}
}
Your implementation is calling getAllNodesRecursively
recursively, but ignoring its return value.
Yes it's possible, just put the yield return
before the foreach
. You are thinking of the behaviour of a normal return
statement.