BST Find Minimum Element in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the left child of the current node.

DSA Typescript

return node[1];

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

A.left

B.right

C.parent

D.value

Attempts:

3 left

💡 Hint

Common Mistakes

Returning node.right instead of node.left

Returning node.value instead of a node reference

In a BST, the minimum element is found by going to the left child repeatedly. So, we return node.left.

2fill in blank

medium

Complete the code to check if the current node has no left child.

DSA Typescript

if (node[1] === null) {

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

A.right

B.value

C.parent

D.left

Attempts:

3 left

💡 Hint

Common Mistakes

Checking node.right instead of node.left

Comparing node.value to null

If node.left is null, it means this node is the smallest in the BST.

3fill in blank

hard

Fix the error in the recursive call to find the minimum node.

DSA Typescript

return findMin(node[1]);

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

A.right

B.parent

C.left

D.value

Attempts:

3 left

💡 Hint

Common Mistakes

Using node.right in recursion

Using node.value instead of a node reference

To find the minimum, we recursively call findMin on the left child.

4fill in blank

hard

Fill both blanks to complete the iterative search for the minimum node.

DSA Typescript

while (current[1] !== null) {
  current = current[2];
}

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

A.left

B.right

C.parent

D.value

Attempts:

3 left

💡 Hint

Common Mistakes

Using right child in the loop condition or update

Using node.value instead of node reference

We keep moving to the left child until there is no left child left.

5fill in blank

hard

Fill all three blanks to complete the function that finds the minimum node recursively.

DSA Typescript

function findMin(node: TreeNode | null): TreeNode | null {
  if (node === null || node[1] === null) {
    return node;
  }
  return findMin(node[2]);
}

const minNode = findMin(root[3]);

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

A.left

B.right

C.parent

D.value

Attempts:

3 left

💡 Hint

Common Mistakes

Using node.right instead of node.left

Adding extra property after root in the last blank

We check if node.left is null to find the minimum, then recurse on node.left. The last blank is empty because root is already the node.