Binary Tree Node Structure in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a binary tree node with a value property.

DSA Javascript

class TreeNode {
  constructor(val) {
    this.val = [1];
    this.left = null;
    this.right = null;
  }
}

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

Aval

Bvalue

Cnode

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different variable name like 'value' instead of 'val'.

Forgetting to assign the value to this.val.

The constructor parameter is named 'val', so we assign this.val = val to store the node's value.

2fill in blank

medium

Complete the code to create a new TreeNode with value 5.

DSA Javascript

const node = new TreeNode([1]);

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

Anull

Bundefined

C'5'

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Passing '5' as a string instead of the number 5.

Passing null or undefined instead of a value.

We pass the number 5 to the TreeNode constructor to create a node with value 5.

3fill in blank

hard

Fix the error in the code to correctly assign the left child of a node.

DSA Javascript

node.[1] = new TreeNode(3);

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Aright

Bchild

Cleft

Dnode

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning to 'right' instead of 'left'.

Using an incorrect property name like 'child' or 'node'.

The left child of a binary tree node is assigned to the 'left' property.

4fill in blank

hard

Fill both blanks to check if a node has a right child and assign it to a variable.

DSA Javascript

if (node.[1] !== [2]) {
  const rightChild = node.right;
}

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

Aright

Bnull

Cleft

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Checking 'left' instead of 'right'.

Comparing to undefined instead of null.

We check if node.right is not null to confirm the right child exists.

5fill in blank

hard

Fill all three blanks to create a node, assign left and right children with values 1 and 2.

DSA Javascript

const root = new TreeNode([1]);
root.[2] = new TreeNode(1);
root.[3] = new TreeNode(2);

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

A0

Bleft

Cright

Droot

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'root' as a property name instead of 'left' or 'right'.

Assigning children to wrong properties.

We create root with value 0, assign left child to 'left', and right child to 'right'.