What Is a Linked List?
A Linked List is a data structure where elements (called nodes) are stored in a chain-like structure. Each node has two parts:
- data (value)
- next (a reference to the next node)
Unlike arrays, linked lists do not store elements in continuous memory. You can imagine it like a person holding the hand of another person, who holds the hand of the next, and so on.
You can imagine each person as one node and the hand connection as the next pointer.
Why Do We Need Linked Lists?
Arrays have a fixed size. If the array becomes full, we must create a new one. Also, inserting in the middle requires shifting elements. Linked Lists solve these problems.
- Dynamic size – You can grow or shrink the list anytime.
- Easy insertions and deletions – No shifting required – just change pointers.
- Efficient memory usage – Only use memory when you add a new node.
Types of Linked Lists
- Singly Linked List – Each node has two parts: data and next. You can move forward only.
- Doubly Linked List – Each node has three parts: data, next, and previous. You can move in both directions.
- Circular Linked List – The last node points back to the first node (head).
When to Use Linked Lists?
- You need frequent insert/delete operations
- You don’t know the exact size in advance
- You want dynamic memory usage
- You need to build stacks, queues, or adjacency lists
Basic Operations on Linked List
When you start learning data structures, every beginner should know:
- Insert at the beginning
- Insert at the end
- Insert at any position
- Delete first
- Delete last
- Delete by value/index
- Search for an element
- Traverse (print all elements)
- Reverse a linked list
In the next chapter of this tutorial, you will implement these operations in Java.
Advantages of Linked List
- No size limit
- Easy insertions and deletions
- Efficient memory usage
- Good for dynamic data
Disadvantages of Linked List
- Slow access — cannot directly access the index
- Uses extra memory due to pointers
- Not cache-friendly