uber-TPS question

NodeDereference.java

import java.util.*;

public class Question {
    class Node {
        // A unique ID of a node
        int id;
        // Arbitrary value
        String name;
        // A list of child node IDs
        ArrayList<Integer> references;
        // A list of child nodes
        ArrayList<Node> children;
        public Node(int id, String name, ArrayList<Integer> references) {
            this.id = id;
            this.name = name;
            this.references = references;
            this.children = new ArrayList<Node>();
        }
    }

    /**
     * Dereferences a node object by adding referenced nodes as children of a
     * node.
     * @param node  a Node object to be dereferenced
     * @param nodes a list of all possible children nodes
     * @return      a dereferenced node
     */
    public static Node dereference(Node inputNode, ArrayList<Node> nodes) {
 	//TODO: type your code here
    }

    public static void main(String[] args) {
        Question q = new Question();
        q.test();
    }

    public void test() {
        // node1 = {'id': 1,  'name': 'McDonalds',  'references': [20, 21], 'children': []}
        ArrayList<Integer> references1 = new ArrayList<Integer>();
        references1.add(20);
        references1.add(21);
        Node node1 = new Node(1, "McDonalds", references1);

        // node2 = {'id': 20, 'name': 'Dinner',     'references': [80],     'children': []}
        ArrayList<Integer> references2 = new ArrayList<Integer>();
        references2.add(80);
        references2.add(1);
        Node node2 = new Node(20, "Lunch", references2);

        // node3 = {'id': 21, 'name': 'Lunch',      'references': [80],     'children': []}
        ArrayList<Integer> references3 = new ArrayList<Integer>();
        references3.add(80);
        Node node3 = new Node(21, "Dinner", references3);

        // node4 = {'id': 80, 'name': 'Hamburger',  'references': [],       'children': []}
        ArrayList<Integer> references4 = new ArrayList<Integer>();
        Node node4 = new Node(80, "Hamburger", references4);

        ArrayList<Node> nodes = new ArrayList<Node>();
        nodes.add(node1);
        nodes.add(node2);
        nodes.add(node3);
        nodes.add(node4);
        Node answer = dereference(node1, nodes);

        System.out.println(answer.references); // [20, 21]
        System.out.println(answer.children); // [node2, node3]
        System.out.println(answer.children.get(0).id); // 20
        System.out.println(answer.children.get(1).id); // 21
        
        System.out.println(answer.children.get(0).references); // [80]
        System.out.println(answer.children.get(0).children.get(0).id); // 80
        
        System.out.println(answer.children.get(1).references); // [80]
        System.out.println(answer.children.get(1).children.get(0).id); // 80
    }
}