Java.util.LinkedList.offer(), offerFirst(), offerLast() in Java

offerFirst(Element x)

Function: This method adds the element at the front of this list.

Syntax: public boolean offerFirst(Element x)

Parameter: x - the element to be added

Return value: boolean function so it will return true.

Example of this method with the help of a code

Code

// Demonstration of offerFirst(Element x) in linked list
import java.util.*;
public class Solution {

      public static void main(String[] args){

            // Declaring a LinkedList
            LinkedList list = new LinkedList();

           // adding elements
           list.add("Coding");
           list.add("Ninjas");

           // printing the list
          System.out.println("The initial Linked list is : " + list);

          //adds at the element at the head of the list
          list.offerFirst("Coding Ninjas Studio");

 
         System.out.println("LinkedList after insertion using offerFirst() : " + list);
    }
}

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Output

Time Complexity: O(1)

Space Complexity: O(1)

offerLast(Element x)

Function: This method adds the element at the end of this list.

Syntax: public boolean offerLast(Element x)

Parameter: x - the element to be added

Return value: boolean function so it will return true.

Example of this method with the help of the code.

Code

// Java code to demonstrate the working
// Demonstration of offerLast(Element x) in linked list
import java.util.*;
public class Solution {

      public static void main(String[] args){

            // Declaring a LinkedList
            LinkedList list = new LinkedList();

            // adding elements
            list.add("Coding");
            list.add("Ninjas");

           // printing the list
          System.out.println("The initial Linked list is : " + list);

         // offering a new element
        // adds element at end.
        list.offerLast("Coding Ninjas Studio");

      // printing the new list
      System.out.println("LinkedList after using offerLast() : " + list);
    }
}

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Output

Time Complexity: O(1)

Space Complexity: O(1)

Practical Application

The flexible addition of these functions can be done in priority addition in queues where items with a larger number than the threshold must be handled before those with a lower number.

An example of this is discussed in the code below for better understanding.

Code

// Demonstration of the application
// of offer() in linked list
import java.util.*;
public class Solution {

   public static void main(String[] args){

      // Declaring LinkedLists
      LinkedList<Integer> list = new LinkedList<Integer>();
      LinkedList list2 = new LinkedList();

     // adding elements
     list.add(12);
     list.add(4);
     list.add(8);
     list.add(15);

     // declaring threshold
     int thres = 8;

    // printing the list without using the function
    System.out.println("The initial LinkedList is : " + list);

   while (!list.isEmpty()) {

      int t = list.poll();

      if (t >= 8)
        list2.offerFirst(t);
        
      else
        list2.offerLast(t);
   }

   // The Final list is
   System.out.println("The prioritized LinkedList is : " + list2);
  }
}

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Output

Check out this problem - Check If A String Is Palindrome

Frequently Asked Questions

What do you mean by LinkedList data structure?

LinkedList is a linear data structure where elements are connected through links in non-contiguous locations. Each element is known as a node. There are three types of LinkedList known as Singly LinkedList, Doubly LinkedList, and Circular LinkedList.

What are the three additional methods of the Java LinkedList class?

Three functions are offer, offerFirst(), and offerLast(), which helps elements get inserted at the front and rear end of the list.

Conclusion

In this blog, we learn about the additional methods of the Java LinkedList class that helps us to add the specified elements at specified positions. We understand their syntax and function with the help of examples.

Recommended Reading:

• Java List Iterator
• Advantages and Limitations of Linked List
• Application of Linked List
• Linked List removefirst Method in Java
• Linked List add Method in Java
• Linked List addall Method in Java
• Linked List listiterator in Java

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