Introduce Java LinkedList and give examples
In Java, a LinkedList
is a part of the Java Collections Framework and is implemented as a doubly linked list. It allows for the storage of a sequence of elements, where each element (or node) contains a reference to both the next and the previous node in the sequence. This structure allows for efficient insertion and removal of elements from both ends of the list, making it a good choice for scenarios where frequent modifications to the list are required.
LinkedList
:add(E e)
: Appends the specified element to the end of the list.addFirst(E e)
: Inserts the specified element at the beginning of the list.addLast(E e)
: Appends the specified element to the end of the list (same as add
).remove(Object o)
: Removes the first occurrence of the specified element from the list.removeFirst()
: Removes and returns the first element from the list.removeLast()
: Removes and returns the last element from the list.get(int index)
: Returns the element at the specified position in the list.size()
: Returns the number of elements in the list.LinkedList
:Here’s a simple example demonstrating how to use a LinkedList
in Java:
import java.util.LinkedList;
public class LinkedListExample {
public static void main(String[] args) {
// Create a LinkedList
LinkedList<String> linkedList = new LinkedList<>();
// Add elements to the LinkedList
linkedList.add("Apple");
linkedList.add("Banana");
linkedList.add("Cherry");
linkedList.addFirst("Mango"); // Adding at the beginning
linkedList.addLast("Orange"); // Adding at the end
// Display the LinkedList
System.out.println("LinkedList: " + linkedList);
// Access elements
String firstElement = linkedList.get(0);
System.out.println("First Element: " + firstElement);
// Remove elements
linkedList.remove("Banana"); // Remove by value
linkedList.removeFirst(); // Remove first element
linkedList.removeLast(); // Remove last element
// Display the LinkedList after removals
System.out.println("LinkedList after removals: " + linkedList);
// Size of the LinkedList
System.out.println("Size of LinkedList: " + linkedList.size());
}
}
LinkedList: [Mango, Apple, Banana, Cherry, Orange]
First Element: Mango
LinkedList after removals: [Apple, Cherry]
Size of LinkedList: 2
The LinkedList
class in Java is a versatile data structure that is particularly useful when you need to frequently add or remove elements. It provides a simple and efficient way to manage a collection of items while maintaining their order.