[SilverMage]

Hello,

I'm having trouble removing nodes from a binary search tree that I'm implementing. In the particular method below, I made it so that the node that I want to get rid of is overridden by its child. In this case, I'm trying to get rid of the minimum, so either there is one child or none. However, when I view all the elements of the tree after doing one deletion, the element I deleted is still showing up. What am I doing wrong here?

if(r.left != null)
        {
            return deleteMin(r.left);
        }
        
if(r.right != null)
        {
            AnyType data = (AnyType) r.items.data;
            r = r.right;
            return data;
        }
        
        AnyType data = (AnyType) r.items.data;
        r = null;
        return data;

[macosxnerd101]

When you say r = null; you are just telling the variable not to point to an Object in memory. If you want to remove a Node, you have to make sure its parent is no longer pointing to it. So if parent.left = null, then the Object parent.left points to in memory will be garbage collected.

[baavgai]

Your minimum node would be the left most node. You'd find the node that's the parent of the left most node and then just make left=null. There would be a loop or recursive call to get to that node. It's unclear from your code that you're actually going there. Or why you're messing about with right.

[macosxnerd101]

Quote

Or why you're messing about with right.

If the far-left Node has a right child, that child has to be handled somehow.

[baavgai]

Agreed. It's just unclear we've gotten that far.