Can you explain what a linked list is and its main features?

A linked list is a data structure consisting of nodes, where each node contains data and a reference (or references) to the next (and/or previous) node. Main features:

• Dynamic memory allocation: the size of the list can change during runtime.
• Elements are not stored in contiguous memory cells but are linked through pointers.
• Fast addition and removal of elements in the middle of the list without shifting other elements.
• No direct access by index; to get an element, you need to traverse from the beginning through links.

Example of a singly linked list in C#:

class Node {
    public int Data;
    public Node Next;

    public Node(int data) {
        Data = data;
        Next = null;
    }
}

class LinkedList {
    public Node Head;

    public void Add(int data) {
        Node newNode = new Node(data);
        if (Head == null) {
            Head = newNode;
        } else {
            Node current = Head;
            while (current.Next != null) {
                current = current.Next;
            }
            current.Next = newNode;
        }
    }
}