What is a linked list?

A linked list is a data structure used in computer science to organize and store data. It consists of a sequence of elements, each contained in a “node.” The unique feature of a linked list is that each node contains a reference (or link) to the next node in the sequence, allowing for efficient insertions and deletions. Linked lists can be used to implement several other common abstract data types, including stacks, queues, and associative arrays.

### Characteristics of a Linked List:
1. Dynamic Data Structure: Linked lists are dynamic, meaning they can grow or shrink in size during the execution of a program. They allocate memory as needed, unlike arrays, which need a fixed size beforehand.

2. Efficient Insertions/Deletions: Adding or removing elements from a linked list is generally more efficient than doing so with arrays, as there’s no need to shift elements.

3. Sequential Access: Elements in a linked list can only be accessed sequentially, starting from the first node. This makes accessing a specific element potentially slower than with arrays, where direct indexing is possible.

4. Memory Overhead: Each element in a linked list requires additional memory for the reference to the next (and possibly previous) node, making them less memory efficient than arrays for storing the same number of values.

### Types of Linked Lists:
1. Singly Linked List: Each node contains a value and a reference to the next node in the sequence.

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