BST Inorder Successor in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the left child of a node in a BST.

DSA Javascript

function leftChild(node) {
  return node[1];
}

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

A.left

B.right

C.parent

D.child

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.right' instead of '.left' to access the left child.

Using '.parent' which points to the parent node, not the child.

In a BST, the left child of a node is accessed using the '.left' property.

2fill in blank

medium

Complete the code to find the minimum node in a BST subtree.

DSA Javascript

function findMin(node) {
  while (node[1]) {
    node = node.left;
  }
  return node;
}

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

A.right

B.child

C.parent

D.left

Attempts:

3 left

💡 Hint

Common Mistakes

Checking '.right' instead of '.left' in the loop condition.

Not updating the node inside the loop.

To find the minimum node, keep going left until there is no left child.

3fill in blank

hard

Fix the error in the code to find the inorder successor when the node has no right child.

DSA Javascript

function inorderSuccessor(node) {
  if (node.right) {
    return findMin(node.right);
  }
  let parent = node[1];
  while (parent && node === parent.right) {
    node = parent;
    parent = parent.parent;
  }
  return parent;
}

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

A.parent

B.left

C.right

D.child

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.left' or '.right' instead of '.parent' to move up the tree.

Not updating the parent inside the loop.

To move up the tree, we use the '.parent' property to find the parent node.

4fill in blank

hard

Fill both blanks to complete the function that finds the inorder successor of a node in a BST.

DSA Javascript

function inorderSuccessor(node) {
  if (node.right) {
    return [1](node.right);
  }
  let parent = node.[2];
  while (parent && node === parent.right) {
    node = parent;
    parent = parent.parent;
  }
  return parent;
}

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

AfindMin

BfindMax

Cparent

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'findMax' instead of 'findMin' for the right subtree.

Using 'right' or 'left' instead of 'parent' to move up.

If the node has a right child, the successor is the minimum node in the right subtree (findMin). Otherwise, move up using the 'parent' property, which is accessed by 'node.parent'.

5fill in blank

hard

Fill all three blanks to complete the function that returns the inorder successor of a node in a BST.

DSA Javascript

function inorderSuccessor(node) {
  if (node.[1]) {
    return findMin(node.[2]);
  }
  let parent = node.[3];
  while (parent && node === parent.right) {
    node = parent;
    parent = parent.parent;
  }
  return parent;
}

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

Aright

Cparent

Dleft

Attempts:

3 left

💡 Hint

Common Mistakes

Using different properties for the first two blanks.

Using 'left' instead of 'parent' to move up.

The function checks if the node has a right child (node.right). If yes, it finds the minimum node in the right subtree (node.right). Otherwise, it moves up the tree using the parent property (node.parent).