Doubly Linked List Structure and Node Design in DSA C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a doubly linked list?

A doubly linked list is a chain of nodes where each node has two links: one to the next node and one to the previous node. This allows moving forward and backward through the list.

beginner

What are the main parts of a node in a doubly linked list?

A node has three parts: data (the value stored), a pointer to the next node, and a pointer to the previous node.

beginner

Show the C struct for a doubly linked list node.

struct Node { int data; struct Node* prev; struct Node* next; };

intermediate

Why do we need a 'prev' pointer in a doubly linked list node?

The 'prev' pointer allows us to move backward in the list, making it easier to traverse in both directions and to delete or insert nodes efficiently.

beginner

What is the difference between singly and doubly linked list nodes?

Singly linked list nodes have one pointer to the next node only. Doubly linked list nodes have two pointers: one to the next node and one to the previous node.

Which pointer in a doubly linked list node points to the previous node?

A next

B tail

C head

D prev

The 'prev' pointer stores the address of the previous node in the list.

What data type is typically used to store the value in a doubly linked list node in C?

A struct Node*

B char*

C int

D float

Usually, an integer (int) is used to store the data value in simple examples.

How many pointers does each node in a doubly linked list have?

A Two

B One

C Three

D null

Each node has two pointers: one to the next node and one to the previous node.

What is the main advantage of a doubly linked list over a singly linked list?

A Can traverse both forward and backward

B Faster insertion at the end

C Uses less memory

D Simpler node structure

Doubly linked lists allow traversal in both directions because of the 'prev' pointer.

In C, how do you declare a pointer to the next node inside a struct Node?

A int next;

B struct Node* next;

C Node next;

D struct Node next;

You declare it as 'struct Node* next;' to store the address of the next node.

Describe the structure of a node in a doubly linked list and explain the purpose of each part.

Think about what each part stores and why.

Explain how a doubly linked list allows traversal in both directions and why this is useful.

Consider how pointers connect nodes.