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

Practice - 5 Tasks

1fill in blank

easy

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

DSA Javascript

const root = new TreeNode([1]);

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

Anull

B0

C1

D'root'

Attempts:

3 left

💡 Hint

Common Mistakes

Using null or 0 as the root value which may not represent the root meaningfully.

The root node usually has a value, here we assign it the string 'root'.

2fill in blank

medium

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

DSA Javascript

function isLeaf(node) {
  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 !== which would not correctly identify leaf nodes.

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

3fill in blank

hard

Fix the error in the code to calculate the height of a tree node.

DSA Javascript

function height(node) {
  if (!node) return -1;
  let maxChildHeight = -1;
  for (const child of node.children) {
    maxChildHeight = Math.max(maxChildHeight, height(child));
  }
  return maxChildHeight [1] 1;
}

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

A-

B+

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or multiplication which gives wrong height values.

The height of a node is 1 plus the maximum height among its children.

4fill in blank

hard

Fill both blanks to calculate the depth of a node given its parent depth.

DSA Javascript

function depth(node, parentDepth) {
  if (!node) return -1;
  node.depth = parentDepth [1] 1;
  for (const child of node.children) {
    depth(child, node.depth [2] 0);
  }
}

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

A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or multiplication which gives incorrect depths.

Depth of a node is parent's depth plus 1. We pass this updated depth to children.

5fill in blank

hard

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

DSA Javascript

function getLevel(node) {
  if (!node.parent) return [1];
  return getLevel(node.parent) [2] [3];
}

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

A0

B+

C1

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 as root level or subtracting which gives wrong levels.

The root node has level 0. For other nodes, level is parent's level plus 1.