Tree vs Array vs Linked List When Hierarchy Matters in DSA Javascript - Interactive Comparison Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple array representing a list of fruits.

DSA Javascript

const fruits = ['apple', [1], 'banana'];
console.log(fruits);

Drag options to blanks, or click blank then click option'

A'potato'

B'carrot'

C'orange'

D'lettuce'

Attempts:

3 left

💡 Hint

Common Mistakes

Adding a vegetable instead of a fruit.

The array should contain fruit names. 'orange' fits correctly between 'apple' and 'banana'.

2fill in blank

medium

Complete the code to link nodes in a singly linked list.

DSA Javascript

function Node(value) {
  this.value = value;
  this.next = [1];
}

const first = new Node(1);
const second = new Node(2);
first.next = second;
console.log(first.next.value);

Drag options to blanks, or click blank then click option'

Anull

B0

Csecond

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Using undefined or a variable that is not yet defined.

When creating a new node, its next pointer should start as null to indicate the end of the list.

3fill in blank

hard

Fix the error in the tree node constructor to correctly assign children as an empty array.

DSA Javascript

function TreeNode(value) {
  this.value = value;
  this.children = [1];
}

const root = new TreeNode('root');
console.log(root.children.length);

Drag options to blanks, or click blank then click option'

Aundefined

B{}

Cnull

D[]

Attempts:

3 left

💡 Hint

Common Mistakes

Using object literal {} instead of array [] for children.

Children should be an empty array to hold multiple child nodes in a tree structure.

4fill in blank

hard

Fill both blanks to create a linked list node and link it to the next node.

DSA Javascript

function ListNode(value) {
  this.value = value;
  this.next = [1];
}

const node1 = new ListNode(10);
const node2 = new ListNode(20);
node1.next = [2];
console.log(node1.next.value);

Drag options to blanks, or click blank then click option'

Anull

Bnode2

Cundefined

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting next to undefined or 0 instead of null.

Not linking node1 to node2 correctly.

When creating a new node, next is initially null. Then node1.next is set to node2 to link them.

5fill in blank

hard

Fill all three blanks to create a tree node, add a child, and print the child's value.

DSA Javascript

function TreeNode(value) {
  this.value = value;
  this.children = [1];
}

const parent = new TreeNode('parent');
const child = new TreeNode('child');
parent.children.[2](child);
console.log(parent.children[[3]].value);

Drag options to blanks, or click blank then click option'

A[]

Bpush

C0

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop instead of push.

Using wrong index to access child.

Children is an empty array. Use push to add the child. The first child's index is 0.