BST Find Minimum Element in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the minimum value in a BST by going left.

DSA C++

int findMin(Node* root) {
    while (root->[1] != nullptr) {
        root = root->left;
    }
    return root->data;
}

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

Aleft

Bparent

Cright

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'right' instead of 'left' to find the minimum.

Trying to access a non-existent 'parent' pointer.

In a BST, the minimum element is found by continuously moving to the left child until there is no left child.

2fill in blank

medium

Complete the code to handle the case when the BST is empty.

DSA C++

int findMin(Node* root) {
    if (root == [1]) {
        return -1; // or some error code
    }
    while (root->left != nullptr) {
        root = root->left;
    }
    return root->data;
}

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

Anullptr

B0

CNULL

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 or NULL instead of nullptr in modern C++.

Not checking for empty tree before accessing nodes.

We check if the root pointer is nullptr to know if the tree is empty.

3fill in blank

hard

Fix the error in the recursive version of findMin function.

DSA C++

int findMin(Node* root) {
    if (root == nullptr) {
        return -1;
    }
    if (root->[1] == nullptr) {
        return root->data;
    }
    return findMin(root->left);
}

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

Aright

Bparent

Cchild

Dleft

Attempts:

3 left

💡 Hint

Common Mistakes

Checking right child instead of left child.

Using an incorrect pointer name.

The base case checks if the left child is nullptr to find the minimum node.

4fill in blank

hard

Fill both blanks to complete the iterative findMin function with a for loop.

DSA C++

int findMin(Node* root) {
    for (; root != [1]; root = root->[2]) {
        if (root->left == nullptr) {
            break;
        }
    }
    return root->data;
}

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

Anullptr

BNULL

Cleft

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Using NULL instead of nullptr.

Moving to the right child instead of left.

The loop continues until root->left is nullptr, moving left each time to find the minimum.

5fill in blank

hard

Fill all three blanks to create a recursive function that returns the minimum value in a BST.

DSA C++

int findMin(Node* root) {
    if (root == [1]) {
        return -1;
    }
    if (root->[2] == [3]) {
        return root->data;
    }
    return findMin(root->left);
}

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

Anullptr

Bleft

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Checking right child instead of left child.

Not checking for empty tree first.

Check if root is nullptr first, then if left child is nullptr to find minimum recursively.