Searching in BST in Data Structures Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if a value exists in a BST.

Data Structures Theory

def search_bst(node, value):
    if node is None:
        return False
    if node.val == [1]:
        return True
    elif value < node.val:
        return search_bst(node.left, value)
    else:
        return search_bst(node.right, value)

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

Anode.left

Bnode.val

Cvalue

Dnode.right

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing node.val to itself instead of the search value.

The function compares the current node's value with the target value. If they are equal, it returns True.

2fill in blank

medium

Complete the code to decide which subtree to search next in a BST.

Data Structures Theory

def search_bst(node, value):
    if node is None:
        return False
    if node.val == value:
        return True
    elif value [1] node.val:
        return search_bst(node.left, value)
    else:
        return search_bst(node.right, value)

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

A>=

B>

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using > instead of < causes searching the wrong subtree.

If the value is less than the current node's value, the search continues in the left subtree.

3fill in blank

hard

Fix the error in the base case of the BST search function.

Data Structures Theory

def search_bst(node, value):
    if node == [1]:
        return False
    if node.val == value:
        return True
    elif value < node.val:
        return search_bst(node.left, value)
    else:
        return search_bst(node.right, value)

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

ANone

BTrue

CFalse

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing node to 0 or boolean values instead of None.

The base case checks if the node is None, meaning the search reached a leaf without finding the value.

4fill in blank

hard

Fill both blanks to complete the recursive BST search function correctly.

Data Structures Theory

def search_bst(node, value):
    if node == [1]:
        return False
    if node.val == value:
        return True
    elif value [2] node.val:
        return search_bst(node.left, value)
    else:
        return search_bst(node.right, value)

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

ANone

B>

C<

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators or incorrect base case check.

The function first checks if the node is None. Then it compares if the value is less than the node's value to decide the subtree.

5fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps node values to their search result in BST.

Data Structures Theory

results = {: search_bst(root, {BLANK_2}}) for {{BLANK_2}} in values

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

A{

Bv

Cvalue

Dvalues

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names or missing braces.

This dictionary comprehension creates a dictionary where keys are values from values list and values are the result of searching each value in the BST.