Question

I’m stuck at finding a solution. C#, .NET 4.0, VS2010

I can easily write a recursive one, but can’t for the life of me figure out something that won’t overflow the stack if the tree is arbitrarily large.

This is a binary tree question, and i am trying to write a

public IEnumerable<T> Values()

method.

Here is the full code in case you are interested: http://pastebin.com/xr2f3y7g

Obviously, the version currently in there doesn’t work. I probably should mention that I am a newbie in C#, transitioning from C++.

Answer 1

Here is a method for inorder traversal, that uses explicit stack. The stack is created on the heap, so it can be much larger, than the stack the processor uses.

public IEnumerable<T> Values()
{
    Stack<Node> stack = new Stack<Node>();
    Node current = this.root;
    while(current != null)
    {
        while(current.leftChild != null)
        {
            stack.Push(current);
            current = current.leftChild;
        }
        yield return current.data;
        while(current.rightChild == null && stack.Count > 0)
        {
            current = stack.Pop();
            yield return current.data;
        }
        current = current.rightChild;
    }

}

If you can’t use a stack and your nodes happen to have parent pointers, you can try solutions from this question