Tree Terminology Root Leaf Height Depth Level in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the root node of a tree.

DSA C++

struct Node {
    int data;
    Node* left;
    Node* right;
};

Node* [1] = nullptr;  // Root node pointer

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

Aroot

Bheight

Cleaf

Dlevel

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'leaf' instead of 'root' for the top node pointer.

Confusing 'height' or 'level' as variable names for the root.

The root node is the topmost node of a tree. We usually name its pointer root.

2fill in blank

medium

Complete the code to check if a node is a leaf (no children).

DSA C++

bool isLeaf(Node* node) {
    return node->left == nullptr && node->[1] == nullptr;
}

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Aright

Bparent

Croot

Dlevel

Attempts:

3 left

💡 Hint

Common Mistakes

Checking only one child pointer.

Using 'parent' or 'root' instead of 'right' pointer.

A leaf node has no children, so both left and right pointers are nullptr.

3fill in blank

hard

Fix the error in the function that calculates the height of a tree node.

DSA C++

int height(Node* node) {
    if (node == nullptr) return 0;
    int leftHeight = height(node->left);
    int rightHeight = height(node->[1]);
    return 1 + (leftHeight > rightHeight ? leftHeight : rightHeight);
}

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Alevel

Bparent

Croot

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'parent' or 'root' instead of 'right' pointer.

Returning incorrect height calculation.

To calculate height, we need to check both left and right children. The right child pointer is right.

4fill in blank

hard

Fill both blanks to create a function that returns the level (depth) of a node in the tree.

DSA C++

int getLevel(Node* root, Node* node, int level) {
    if (root == nullptr) return 0;
    if (root == node) return [1];
    int downLevel = getLevel(root->left, node, level [2] 1);
    if (downLevel != 0) return downLevel;
    return getLevel(root->right, node, level [2] 1);
}

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Alevel

Blevel + 1

Clevel - 1

Dlevel * 1

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 0 instead of current level when node is found.

Not increasing level when going deeper.

The current level is passed as level. When the node is found, return level. When going deeper, increase level by 1 using level + 1.

5fill in blank

hard

Fill all three blanks to create a function that prints nodes at a given level.

DSA C++

void printLevelNodes(Node* root, int level) {
    if (root == nullptr) return;
    if (level == [1]) {
        std::cout << root->data << " ";
    } else if (level > [2]) {
        printLevelNodes(root->left, level [3] 1);
        printLevelNodes(root->right, level [3] 1);
    }
}

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A1

B0

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Checking if level == 1 instead of 0.

Increasing level instead of decreasing when going down.

Nodes at level 0 are the root nodes. We check if level == 0. If level is greater than 0, we go down by subtracting 1 from level.