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Java Program To Delete Alternate Nodes Of A Linked List

Last Updated : 31 Aug, 2022
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Given a Singly Linked List, starting from the second node delete all alternate nodes of it. For example, if the given linked list is 1->2->3->4->5 then your function should convert it to 1->3->5, and if the given linked list is 1->2->3->4 then convert it to 1->3.

Method 1 (Iterative): 
Keep track of previous of the node to be deleted. First, change the next link of the previous node and iteratively move to the next node.


// Java program to delete alternate
// nodes of a linked list
class LinkedList
    // Head of list
    Node head; 
    // Linked list Node
    class Node
        int data;
        Node next;
        Node(int d)
            data = d;
            next = null;
    void deleteAlt()
       if (head == null)
       Node prev = head;
       Node now =;
       while (prev != null &&
              now != null)
           // Change next link of previous node
           // Free node
           now = null;
           // Update prev and now
           prev =;
           if (prev != null)
              now =;
    // Utility functions
    // Inserts a new Node at front
    // of the list.
    public void push(int new_data)
        /* 1 & 2: Allocate the Node &
                  Put in the data*/
        Node new_node = new Node(new_data);
        // 3. Make next of new Node as head = head;
        // 4. Move the head to point to
        // new Node
        head = new_node;
    // Function to print linked list
    void printList()
        Node temp = head;
        while(temp != null)
           System.out.print( + " ");
           temp =;
     // Driver code
    public static void main(String args[])
        LinkedList llist = new LinkedList();
        /* Constructed Linked List is
           1->2->3->4->5->null */
               "Linked List before calling deleteAlt() ");
               "Linked List after calling deleteAlt() ");
// This code is contributed by Rajat Mishra


List before calling deleteAlt() 
1 2 3 4 5 
List after calling deleteAlt() 
1 3 5 

Time Complexity: O(n) where n is the number of nodes in the given Linked List.

Auxiliary Space: O(1) because it is using constant space

Method 2 (Recursive): 
Recursive code uses the same approach as method 1. The recursive code is simple and short but causes O(n) recursive function calls for a linked list of size n.


/* Deletes alternate nodes of
   a list starting with head */
static Node deleteAlt(Node head)
    if (head == null)
    Node node =;
    if (node == null)
    // Change the next link of head =;
    /* Recursively call for the new
       next of head */ = deleteAlt(;
// This code is contributed by Arnab Kundu

Time Complexity: O(n)

Auxiliary space: O(n) for call stack because using recursion

Please refer complete article on Delete alternate nodes of a Linked List for more details!

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