Floor and Ceil in BST in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the floor value in a BST.

DSA C++

int floorInBST(Node* root, int key) {
    int floor = -1;
    while (root != nullptr) {
        if (root->data == key) {
            floor = root->data;
            break;
        } else if (root->data > key) {
            root = root->[1];
        } else {
            floor = root->data;
            root = root->right;
        }
    }
    return floor;
}

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

Achild

Bright

Cparent

Dleft

Attempts:

3 left

💡 Hint

Common Mistakes

Moving to right child when current node's data is greater than key.

Using parent pointer which may not exist.

When the current node's data is greater than the key, we move to the left child to find a smaller or equal value.

2fill in blank

medium

Complete the code to find the ceil value in a BST.

DSA C++

int ceilInBST(Node* root, int key) {
    int ceil = -1;
    while (root != nullptr) {
        if (root->data == key) {
            ceil = root->data;
            break;
        } else if (root->data < key) {
            root = root->[1];
        } else {
            ceil = root->data;
            root = root->left;
        }
    }
    return ceil;
}

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

Aright

Bleft

Cparent

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Moving to left child when current node's data is less than key.

Using parent pointer which may not exist.

When the current node's data is less than the key, we move to the right child to find a larger or equal value.

3fill in blank

hard

Fix the error in the code to correctly find the floor in BST.

DSA C++

int floorInBST(Node* root, int key) {
    int floor = -1;
    while (root != nullptr) {
        if (root->data == key) {
            floor = root->data;
            break;
        } else if (root->data < key) {
            floor = root->data;
            root = root->[1];
        } else {
            root = root->left;
        }
    }
    return floor;
}

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

Aleft

Bright

Cparent

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Moving to left child when current node's data is less than key.

Using parent pointer which may not exist.

When current node's data is less than key, we move to the right child to find a closer or equal value.

4fill in blank

hard

Fill both blanks to complete the code that finds ceil in BST.

DSA C++

int ceilInBST(Node* root, int key) {
    int ceil = -1;
    while (root != nullptr) {
        if (root->data == key) {
            ceil = root->data;
            break;
        } else if (root->data > key) {
            ceil = root->data;
            root = root->[1];
        } else {
            root = root->[2];
        }
    }
    return ceil;
}

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

Aleft

Bright

Cparent

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping left and right child pointers.

Using parent pointer which may not exist.

When current node's data is greater than key, move left to find smaller or equal values. Otherwise, move right to find larger values.

5fill in blank

hard

Fill all three blanks to complete the code that finds floor and ceil in BST.

DSA C++

pair<int, int> floorAndCeil(Node* root, int key) {
    int floor = -1, ceil = -1;
    while (root != nullptr) {
        if (root->data == key) {
            floor = root->data;
            ceil = root->data;
            break;
        } else if (root->data < key) {
            floor = root->data;
            root = root->[1];
        } else {
            ceil = root->data;
            root = root->[2];
        }
    }
    return {floor, ceil};
}

int main() {
    Node* root = nullptr;
    // Assume BST is built here
    int key = 15;
    auto result = floorAndCeil(root, key);
    cout << "Floor: " << result.[3] << ", Ceil: " << result.second << endl;
    return 0;
}

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

Aright

Bleft

Cfirst

Dsecond

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping left and right pointers.

Accessing wrong pair element for floor.

When current node's data is less than key, move right to find closer floor. When greater, move left to find closer ceil. The floor value is stored in the first element of the pair.