BST Insert Operation in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new node with the given value.

DSA Javascript

function createNode(value) {
  return {
    value: value,
    left: null,
    right: null
  };
}

const newNode = [1](10);

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

AinsertNode

BNode

CcreateNode

DnewNode

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that does not exist like insertNode.

Trying to use 'new' keyword with a plain object function.

The function to create a new node is named createNode, so calling createNode(10) creates the new node.

2fill in blank

medium

Complete the code to insert a value into the BST recursively.

DSA Javascript

function insertNode(root, value) {
  if (root === null) {
    return createNode(value);
  }
  if (value [1] root.value) {
    root.left = insertNode(root.left, value);
  } else {
    root.right = insertNode(root.right, value);
  }
  return root;
}

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

A===

B<

C>

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<' causes wrong subtree traversal.

Using '===' or '!==' causes logic errors.

In BST, if the value to insert is less than the current node's value, we go to the left subtree.

3fill in blank

hard

Fix the error in the insert function to correctly handle duplicate values by ignoring them.

DSA Javascript

function insertNode(root, value) {
  if (root === null) {
    return createNode(value);
  }
  if (value < root.value) {
    root.left = insertNode(root.left, value);
  } else if (value > root.value) {
    root.right = insertNode(root.right, value);
  } else {
    [1];
  }
  return root;
}

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

Aroot.value = value

Breturn null

CinsertNode(root, value)

Dreturn root

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to insert duplicates again causing infinite recursion.

Replacing root.value overwrites existing node.

When the value equals root.value, we do nothing and return the current root to ignore duplicates.

4fill in blank

hard

Fill both blanks to insert multiple values into the BST using a loop.

DSA Javascript

function buildBST(values) {
  let root = null;
  for (let [1] = 0; [2] < values.length; [1]++) {
    root = insertNode(root, values[[1]]);
  }
  return root;
}

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

Ai

Bj

Cvalues.length

Droot

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong loop variable names inconsistently.

Incorrect loop condition causing infinite or no iteration.

The loop variable is 'i' and the condition is 'i < values.length' to iterate over all values.

5fill in blank

hard

Fill all three blanks to print the BST values in ascending order using in-order traversal.

DSA Javascript

function inOrderTraversal(root, result) {
  if (root !== null) {
    inOrderTraversal(root.[1], result);
    result.push(root.[2]);
    inOrderTraversal(root.[3], result);
  }
}

const result = [];
inOrderTraversal(bstRoot, result);
console.log(result);

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

Aleft

Bvalue

Cright

Droot

Attempts:

3 left

💡 Hint

Common Mistakes

Visiting right child before left causes descending order.

Pushing root instead of root.value causes wrong output.

In-order traversal visits left subtree, then node value, then right subtree to get sorted order.