LinkedList in Java
In Java, LinkedList is a class that represents a sequence of elements. Each element in the LinkedList is represented by a node object, which has a reference to the next element in the list. The LinkedList class provides methods to add, remove, and access elements in the list.
LinkedList in Java is implemented as a doubly-linked list, which means that each node in the list has a reference to the next and previous nodes in the list. This allows for efficient traversal of the list in either direction.
Unlike array, which has a fixed size, LinkedList can grow or shrink dynamically as elements are added or removed from the list. This makes LinkedList a flexible and efficient data structure for managing dynamic collections of data.
LinkedList in Java is part of the Java Collection Framework, which is a set of classes and interfaces that provides a unified interface for working with collections of objects in Java. The LinkedList class implements the List interface, which provides methods for working with ordered collections of objects.
Example:
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import java.util.LinkedList; public class LinkedListExample { public static void main(String[] args) { // Create a new LinkedList LinkedList<String> list = new LinkedList<String>(); // Add elements to the LinkedList list.add("Apple"); list.add("Banana"); list.add("Cherry"); // Print the LinkedList System.out.println("LinkedList: " + list); // Get the first element of the LinkedList String first = list.getFirst(); System.out.println("First element: " + first); // Get the last element of the LinkedList String last = list.getLast(); System.out.println("Last element: " + last); // Remove the first element from the LinkedList String removed = list.removeFirst(); System.out.println("Removed element: " + removed); // Print the LinkedList again System.out.println("LinkedList: " + list); } } |
The output of this program will be:
First element: Apple
Last element: Cherry
Removed element: Apple
LinkedList: [Banana, Cherry]
Use Cases:
LinkedLists are commonly used in a variety of use cases, including:
- Implementing stacks and queues: LinkedList can be used to implement stacks and queues, which are data structures that allow elements to be added or removed in a specific order.
- Managing large data sets: LinkedList is well-suited for managing large data sets because it can be easily resized as needed. This makes it useful for applications that need to store and manage large amounts of data, such as data analytics or machine learning.
- Iterating through collections: LinkedList provide efficient traversal of collections because each node only needs to hold a reference to the next node in the sequence. This makes it easy to iterate through the collection in order.
Performance:
LinkedList provide constant time performance for adding or removing elements from the beginning or end of the list, as well as for accessing elements by index. However, accessing elements in the middle of the list requires traversing the list from the beginning or end, which can be slow for large lists.
Additionally, LinkedList use more memory than array because each node requires a reference to the next node in the sequence. This can lead to increased memory usage and decreased performance if a large number of nodes are added to the list.
In general, LinkedList is a good choice for managing dynamic collections of data, especially when elements need to be added or removed frequently. However, it may not be the best choice for applications that require fast random access to elements in the middle of the list or for applications with memory constraints.