BST Find Maximum Element in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the maximum value in a BST by moving right.

DSA Typescript

function findMax(root: TreeNode | null): number | null {
  if (root === null) return null;
  let current = root;
  while (current.[1] !== null) {
    current = current.right;
  }
  return current.val;
}

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

Aleft

Bparent

Cright

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'left' instead of 'right' to traverse.

Returning root value without traversal.

In a BST, the maximum value is found by moving to the right child until there is no more right child.

2fill in blank

medium

Complete the code to recursively find the maximum value in a BST.

DSA Typescript

function findMaxRecursive(root: TreeNode | null): number | null {
  if (root === null) return null;
  if (root.[1] === null) return root.val;
  return findMaxRecursive(root.right);
}

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

Aright

Bparent

Cleft

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Checking left child instead of right.

Not handling null root case.

The recursion stops when there is no right child, meaning the current node is the maximum.

3fill in blank

hard

Fix the error in the code to correctly find the maximum value in a BST iteratively.

DSA Typescript

function findMaxIterative(root: TreeNode | null): number | null {
  if (root === null) return null;
  let current = root;
  while (current.[1] !== null) {
    current = current.[1];
  }
  return current.val;
}

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

Achild

Bleft

Cparent

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Moving left instead of right in the loop.

Returning wrong node value.

To find the maximum, we must move right, not left.

4fill in blank

hard

Fill both blanks to create a function that finds the maximum value in a BST using recursion.

DSA Typescript

function findMax(root: TreeNode | null): number | null {
  if (root === null) return null;
  if (root.[1] === null) return root.val;
  return findMax(root.[2]);
}

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

Aright

Bleft

Dparent

Attempts:

3 left

💡 Hint

Common Mistakes

Using left child in conditions.

Not returning the recursive call properly.

The function checks if the right child is null to stop recursion, otherwise it continues to the right child.

5fill in blank

hard

Fill all three blanks to implement an iterative function that finds the maximum value in a BST.

DSA Typescript

function findMax(root: TreeNode | null): number | null {
  if (root === null) return null;
  let [1] = root;
  while ([2].[3] !== null) {
    [2] = [2].right;
  }
  return current.val;
}

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

Acurrent

Broot

Cright

Dleft

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'root' instead of a traversal variable.

Moving left instead of right.

We use a variable 'current' to traverse the tree moving right until no more right child exists.