LinkedList removeFirst method in Java

Introduction

LinkedList removeFirst() method is widely used in codes to optimize the bigger problems of LinkedList to smaller ones. LinkedList is a crucial data structure to prepare for your coding rounds. It is widely used and asked due to its dynamic nature, which eases inserting and deleting elements. To access the nodes easily, LinkedList offers various methods, one of which will be covered in this article, i.e., removeFirst() method.

The removeFirst() method removes the first element from the list, which will return the first element after removing it.

Let’s understand more clearly about this method with its syntax and pictorial representation.

Syntax

The syntax of this method is:

Parameters: It doesn’t take any parameters. It just removes the element and returns it.

Return Value: Returns the first element of the list.

Example:

This is the LinkedList having three nodes: A, B, C, where A is the Head of the LinkedList and C is pointing to the Null.

After using the removeFirst() method on this list.

Output:

A

[B, C]

This will be the final list after using the removeFirst() method. Now will ‘B’ will act as Head for this new LinkedList. 

Code

// Demonstration of removeFirst() method
import java.io.*;
import java.util.LinkedList;

public class Solution {
        public static void main(String args[]){

               // creating the LinkedList which will taking strings as parameters
               LinkedList<String> l1 = new LinkedList<String>();

               // To add elements in the list
                   l1.add("Happy");
                   l1.add("Coding");
                   l1.add("Everyone");

               // Displaying list before using the method
               System.out.println("LinkedList:" + l1);

              // Head is removed using removeFirst() method
              System.out.println("Removed element is: " + l1.removeFirst());

              // Displaying the final list after using the method
              System.out.println("Final LinkedList:" + l1);
          }
}

Output

As you can see first element(head) is removed and returned as the output.

Analysis of Complexity

Time Complexity: O(1), as in the case of LinkedList, the shift is not involved and the removeFirst() method works on the ends of the list so it doesn’t require the traversal.

Space Complexity: O(1), no extra space is required for the removeFirst() method.

FAQ’S

1). What do you mean by LinkedList data structure?

LinkedList is a linear data structure where an element represents a node. Every node is connected via links. Elements are not stored in contiguous locations, and every element has its data and address part.

2). What is the use of the removeFirst() method in LinkedList?

The removeFirst() method is used to remove the first element from the list.

3). Why is LinkedList preferred over Arrays?

Due to its dynamic nature, elements can be easily inserted or deleted, so LinkedList is preferred over Arrays.

Key Takeaways

In this blog, we ran you through the removeFirst() method of LinkedList in Java.

We saw an example for a better understanding of the method. You can see more about LinkedList and its various methods for more optimization in the code.

You can use CodeStudio to practice various DSA questions typically asked in interviews. It will help you in mastering efficient coding techniques.

Keep Coding!!!