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Practice

Creating a Linked List Structure Using Nodes

A Linked List is a data structure where data elements are organized into individual units called Nodes which are interconnected.

Each node is made up of Data and a Pointer pointing to the next node.


Structure and Characteristics of Linked Lists​

Linked lists have the following structure and characteristics.


Node​

The basic unit of a linked list.

Each node contains data and one or two pointers that reference the next node (and sometimes the previous node).


A pointer that references the first node of the linked list.

It signifies the starting point of the linked list.


Tail​

A pointer that references the last node of the linked list.

The pointer in the tail node generally points to None.


How can linked lists be implemented?​

Below is a Python example that implements a Singly Linked List.

Example of a Singly Linked List in Python
class Node:
    def __init__(self, data):
        # Node data
        self.data = data
        # Pointer to the next node
        self.next = None

class LinkedList:
    def __init__(self, data):
        # Create the first node
        self.head = Node(data)
        # Initially, head and tail are the same
        self.tail = self.head

    def append(self, data):
        # Create a new node and link it
        node = Node(data)
        # Link the new node to the tail node
        self.tail.next = node
        # Set the new node as the tail
        self.tail = node

    def print_all(self):
        # Print the linked list
        node = self.head

        # Traverse the nodes while printing data
        while node:
            print(node.data, end=" ")
            node = node.next
        print()

# Create the linked list
linked_list = LinkedList(5)

# Add nodes
linked_list.append(12)
linked_list.append(7)

# Print the linked list
linked_list.print_all()
# Output: 5 12 7

What types of linked lists are there?​

Linked lists are categorized according to how nodes are connected.


Singly Linked List​

The simplest form of a linked list is a singly linked list, where each node points only to the next node.


Doubly Linked List​

In a doubly linked list, each node contains pointers to both the previous and next nodes.

Allows bidirectional traversal, making insertion and deletion more efficient.


Circular Linked List​

In a circular linked list, the last node points to the first node, forming a continuous loop.

Useful for cyclic iterations.


Comparison between Linked Lists and Arrays​

CharacteristicLinked ListArray
Memory AllocationDynamically allocates memoryUses a contiguous block of memory
Insertion/DeletionFast insertion/deletion at specific positionsInefficient insertion/deletion at specific positions
Random AccessCan only be accessed sequentiallyInstant access via indexing

Linked lists excel in memory management and efficient insertion/deletion operations, whereas arrays are better for random access and faster data processing.

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