Tree Terminology Root Leaf Height Depth Level in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create the root node of a tree.

DSA Typescript

const root = new TreeNode([1]);

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

Anull

B0

Cundefined

DrootValue

Attempts:

3 left

💡 Hint

Common Mistakes

Using null or undefined as the root node value.

The root node is created with a value, here represented by rootValue.

2fill in blank

medium

Complete the code to check if a node is a leaf (has no children).

DSA Typescript

function isLeaf(node: TreeNode): boolean {
  return node.children.length [1] 0;
}

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

A>

B===

C<

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using > or < instead of === to check for zero children.

A leaf node has zero children, so we check if node.children.length === 0.

3fill in blank

hard

Fix the error in the function that calculates the depth of a node.

DSA Typescript

function getDepth(node: TreeNode): number {
  if (!node.parent) return [1];
  return 1 + getDepth(node.parent);
}

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

A0

Bnull

C-1

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Returning null or undefined instead of 0 for root depth.

The depth of the root node is 0 because it has no parent.

4fill in blank

hard

Complete the code to calculate the height of a node.

DSA Typescript

function getHeight(node: TreeNode): number {
  if (node.children.length === 0) return [1];
  return 1 + Math.max(...node.children.map(child => getHeight(child)));
}

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

A0

B1

C)

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 1 for leaf height or missing closing parenthesis.

The height of a leaf node is 0. The recursive call needs a closing parenthesis.

5fill in blank

hard

Fill all three blanks to create a function that returns the level of a node in the tree.

DSA Typescript

function getLevel(node: TreeNode): number {
  let level = 0;
  let current = node;
  while (current.[1]) {
    level [2] level + 1;
    current = current.[3];
  }
  return level;
}

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

Aparent

B=

C+=

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Using assignment instead of increment, or wrong property name.

The level is the number of parents from the node to the root. We loop while current.parent exists, increment level with += 1, and move up to current.parent.