Choosing between ArrayList and LinkedList

Photo by Karine Avetisyan on Unsplash

ArrayList and LinkedList are two commonly used data structures in Java and many other programming languages for storing collections of elements. Each of these data structures has its own advantages and disadvantages, and the choice between them depends on the specific requirements of your application. Here's a comparison of ArrayList and LinkedList:

1. Data Structure :

• ArrayList: Implements a dynamic array that can grow or shrink in size as elements are added or removed. It's backed by an array, and elements are stored in contiguous memory locations.
• LinkedList: Implements a doubly-linked list, where each element (node) contains a reference to both the next and previous elements.

2.Access Time :

• ArrayList: Provides faster access time for random access (i.e., accessing elements by index) because it uses an array where elements are stored sequentially in memory. Retrieving elements by index is an O(1) operation.
• LinkedList: Accessing elements by index is slower (O(n)) since you have to traverse the list from the beginning or end to reach the desired element.

3. Insertion and Deletion :

• ArrayList: Insertions and deletions at the end of the list are generally fast (O(1)), but inserting or deleting elements in the middle or at the beginning requires shifting elements, which can be slow (O(n)).
• LinkedList: Insertions and deletions are generally fast (O(1)) because you just need to update references. This makes it efficient for operations in the middle of the list.

4. Memory Usage :

• ArrayList: Tends to use less memory than LinkedList because it only needs to store elements and an array to hold them.
• LinkedList: Requires more memory than ArrayList because it needs to store both the elements and the references (pointers) to the next and previous elements.

5. Iteration :

• ArrayList: Iterating through elements using a for loop or an iterator is generally faster due to better cache locality.
• LinkedList: Iterating through elements can be slower because of the need to follow pointers between nodes.

6. Use Cases :

• Use ArrayList when you need fast random access, and the list's size doesn't change frequently.
• Use LinkedList when you need efficient insertions and deletions, especially in the middle of the list, and you can tolerate slower random access.

7. Complexity Summary :

• ArrayList:
• Random Access: O(1)
• Insertions/Deletions (end): O(1)
• Insertions/Deletions (middle): O(n)
• Memory Usage: Lower
• LinkedList:
• Random Access: O(n)
• Insertions/Deletions (anywhere): O(1)
• Memory Usage: Higher

The choice between ArrayList and LinkedList depends on the specific operations you need to perform frequently in your code. If you need fast random access and don't perform a lot of insertions and deletions, ArrayList is generally a better choice. On the other hand, if you need efficient insertions and deletions and can tolerate slower access times, LinkedList may be more suitable.

Clap 👏 if you like the content and Follow me 💌 if you want to read more such articles. And you can buy me a coffee at BuyMeACoffee ☕

Thanks for reading.

Similar Articles:

Top 10 free and Paid courses to learn Spring Boot

Why Spring Boot is awesome