Parallel tree traversal in C#

Question

I need to traverse a tree quickly, and I would like to do it in parallel. I\'d rather use the parallel extensions than manually spin up a bunch of threads.

My current co

Answer 1

I might be missing something, but I don't see the need for a while at all. The while is just ensuring that you iterate over every node.

Instead just call your function recursively for each node in the tree.

public void Traverse(Node root)
{         
    if (root.Property = someValue) DoSomething(node);    
    Parallel.ForEach(root.Children, node => Traverse(node));
} 

edit: of course the alternative, if you prefer to process horizontally rather than vertically and your expensive operation is DoSomething, is to do the Traverse first.

public IEnumerable Traverse(Node root)
{
    // return all the nodes on this level first, before recurring
    foreach (var node in root.Children)
    {
        if (node.Property == someValue)
            yield return node;
    }

    // next check children of each node
    foreach (var node in root.Children)
    {
        var children = Traverse(node);
        foreach (var child in children)
        {
            yield return child;
        }
    }
}

Parallel.ForEach(Traverse(n), n => DoSomething(n));