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I was asked this an interview at amazon and could not complete this. can I get some help?

am just totally blocked on this. I know what to do but I am having difficulty manipulating the tree. please help.

I am trying to delete and node from an BST. I am able to lookup and find the parent and store it an tree.

package com.test.binarytree;


public class BinaryTreeDelete {
private Node root;

//create null binary tree
public BinaryTreeDelete(){
root = null;
}

//delete
public void delete(int target){
root = delete(root, target);
}

public Node delete(Node node, int target){
NodeWithParent temp = lookupFindParent(root, null, target);

if( node == null){
return null;
}
else{
if( node.left == null || node.right == null) //leaf node
{
//WHAT DO I DO HERE
//temp.parent.left = null;
//temp.parent.right = null;
//return null;
}
if( node.left != null && node.right == null ) //one child only on left
{
//WHAT DO I DO HERE
}
if( node.right != null && node.left == null ) //one child only on right
{
//WHAT DO I DO HERE
}
if( node.left != null && node.right != null ) //two children
{
//WHAT DO I DO HERE
}
}

return null;
}

private NodeWithParent lookupFindParent(Node node, Node parentNode, int target){
if( node == null ){
return null;
}

if( node.data == target){
return new NodeWithParent(node, parentNode);
}
else if( node.data > target ){
parentNode = node;
return lookupFindParent(node.left, parentNode, target);
}
else{
parentNode = node;
return lookupFindParent(node.right, parentNode, target);
}
}

//insert
public void insert(int data){
root = insert(root, data);
}

public Node insert (Node node, int data){
if(node == null){
node = new Node(data);
}
else{
if( data <= node.data ){
node.left = insert(node.left, data);
}
else{
node.right = insert(node.right, data);
}
}

return node;
}

//print tree
public void printTree(){
printTree(root);
System.out.println();
}

//print tree
private void printTree(Node node) {
if (node == null) return;

// left, node itself, right
printTree(node.left);
System.out.print(node.data + " ");
printTree(node.right);
}
//node class
public static class Node{
Node left;
Node right;
int data;

Node(int newNode){
data = newNode;
left = null;
right = null;
}
}

//node class
public static class NodeWithParent{
Node current;
Node parent;

NodeWithParent(Node current, Node parent){
this.current = current;
this.parent = parent;
}
}

public static void main(String[] args) {
BinaryTreeDelete bt = new BinaryTreeDelete();

//insert with inserts - tree increases on right if inserted in order
bt = new BinaryTreeDelete();
bt.insert(5);
bt.insert(3);
bt.insert(7);
bt.insert(1);
bt.insert(4);
bt.insert(6);
bt.insert(9);
bt.printTree();
//bt.delete(3);
//bt.delete(4);
//bt.delete(6);
bt.delete(9);
//bt.delete(5);
bt.printTree();
}

}