I have created a Binary Search Tree
and am trying to delete specific nodes after adding them. I can successfully delete
about 5 Nodes
but when I try to delete a Node with id 109
it just ignores it and nothing happens. I have tried many methods to delete it and it just does not work.
myBinaryTree.deleteNode(myBinaryTree.root, 109);
Here is the delete
method in my Binary Tree.
public Node deleteNode(Node root, int ID){
if (root == null) return root;
if (ID < root.ID)
root.leftChild = deleteNode(root.leftChild, ID);
else if (ID > root.ID)
root.rightChild = deleteNode(root.rightChild, ID);
else
{
if (root.leftChild == null)
return root.rightChild;
else if (root.rightChild == null)
return root.leftChild;
root.ID = minValue(root.rightChild);
root.rightChild = deleteNode(root.rightChild, root.ID);
}
return root;
}
int minValue(Node root)
{
int minv = root.ID;
while (root.leftChild != null)
{
minv = root.leftChild.ID;
root = root.leftChild;
}
return minv;
}
And my Node
:
public class Node {
int ID;
Dancer.Gender gender;
int height;
Node leftChild;
Node rightChild;
Node(int ID, Dancer.Gender gender, int height) {
this.ID = ID;
this.gender = gender;
this.height = ID;
}
public int getID() {
return ID;
}
public void setID(int ID) {
this.ID = ID;
}
}
The ID
works as intended meaning the method deleteNode
gets correct ID, it just does not delete it.
Here is a picture of a the tree I am trying to delete from:
If more information on how I add the nodes etc is needed then I can provide that aswell. It is just so wierd that it all works perfectly until I try to delete node with ID = 109
.
Your code looks fine.
By the way, how did you verify that the node was not deleted ? I just checked your code and printed inorder traversal. And it works fine.
// This is java code.
void inorder(Node root){
if (root ==null)return;
inorder(root.leftChild);
System.out.print(root.ID + " ");
inorder(root.rightChild);
}
// verify deletion by printing inorder traversal before and after
public static void main(String[] args) {
// creating the tree
Node root = new Node(60);
root.leftChild = new Node(40);
root.rightChild = new Node(109);
root.leftChild.leftChild = new Node(20);
root.leftChild.rightChild = new Node(49);
inorder(root); // Printing before deleting
System.out.println();
myBinaryTree.root = deleteNode(myBinaryTree.root, 109); // delete the node and collect the new reference of the root.
inorder(root); // Printing after tree
System.out.println();
}