Singly linked list structure in Data Structures Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a node in a singly linked list with a value and a pointer to the next node.

Data Structures Theory

class Node:
    def __init__(self, value):
        self.value = value
        self.[1] = None

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

Atail

Bprev

Chead

Dnext

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' instead of 'next' for the pointer.

Using 'head' or 'tail' inside the node class.

In a singly linked list, each node has a pointer called next that points to the next node in the list.

2fill in blank

medium

Complete the code to create a new node and link it as the next node of the current node.

Data Structures Theory

current_node.next = [1](10)

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

ANode

BList

CLinkedList

DElement

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong class name to create a node.

Assigning a value directly instead of a node object.

To link a new node, you create an instance of the Node class and assign it to the next pointer.

3fill in blank

hard

Fix the error in the code to correctly traverse a singly linked list until the end.

Data Structures Theory

while current_node.[1] is not None:
    current_node = current_node.next

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

Aprev

Btail

Cnext

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' instead of 'next' in the loop condition.

Checking 'head' or 'tail' which are not node pointers.

To move through a singly linked list, you follow the next pointers until you reach a node where next is None.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each node's value to the value of its next node, or None if there is no next node.

Data Structures Theory

value_map = {node.value: node.[1].[2] if node.[1] else None for node in nodes}

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

Anext

Bvalue

Cprev

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' instead of 'next' for the pointer.

Accessing 'head' or 'prev' which do not exist in nodes.

Each node's next pointer leads to the next node, and we access its value. If there is no next node, we use None.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps each node's value to the value of the node two steps ahead, or None if not available.

Data Structures Theory

two_ahead_map = {node.[1]: node.[2].[3].value if node.[2] and node.[2].[3] else None for node in nodes}

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

Avalue

Bnext

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up 'value' and 'next' in the blanks.

Using 'prev' which does not exist in singly linked lists.

The first blank accesses the current node's value as the key. The second blank is the next pointer to the next node. The third blank is the next pointer from that next node to the node two steps ahead. We then get the value of that node.