Write a Java program to find the middle element of a singly linked list in one pass

The Java code provided demonstrates how to find the middle element of a linked list in a single pass.

The code defines a class named FindMiddle_Element with a main method, which serves as the entry point for the Java program.
Inside the main method, a LinkedList object named col_list is created, which represents the linked list. Note that LinkedList is a custom implementation of a linked list, defined in the same code.
LinkedList.Node is a static inner class within the LinkedList class, representing a node in the linked list. It has a data field to store the data of the node and a next field to store the reference to the next node in the list.
Nodes with data "Blue", "Pink", "Orange", "Yellow", and "White" are added to the col_list using the add method of LinkedList, which appends the nodes to the end of the list.
The code then finds the middle element of the linked list in a single pass. It initializes a current variable to the head of the list and keeps track of the length of the list using a len variable.
It also initializes a middle variable to the head of the list, which will initially point to the first node, and updates it to the next node at every even length of the list.
The code iterates through the linked list using a while loop and updates the middle variable at every even length of the list by moving it to the next node.
Finally, the code prints the length of the linked list and the middle element of the linked list using System.out.println statements.
The output of the program will be the length of the linked list and the middle element of the linked list.

Source Code

import java.util.*;
import test.LinkedList.Node;
public class FindMiddle_Element
{ 
    public static void main(String args[])
	{
      LinkedList col_list = new LinkedList();
      LinkedList.Node head = col_list.head();
      col_list.add( new LinkedList.Node("Blue"));
      col_list.add( new LinkedList.Node("Pink"));
      col_list.add( new LinkedList.Node("Orange"));
      col_list.add( new LinkedList.Node("Yellow"));
      col_list.add( new LinkedList.Node("White"));
 
      //finding middle element of LinkedList in single pass
      LinkedList.Node current = head;
      int len = 0;
      LinkedList.Node middle = head;
 
      while(current.next() != null){
          len++;
          if(len%2 ==0){
              middle = middle.next();
          }
          current = current.next();
      }
 
      if(len%2 == 1){
          middle = middle.next();
      }
 
      System.out.println("Length of LinkedList :  " + len);
      System.out.println("Middle Element of LinkedList : "+ middle);
 
    }
 
}
 
class LinkedList{
    private Node head;
    private Node tail;
 
    public LinkedList(){
        this.head = new Node("head");
        tail = head;
    }
 
    public Node head(){
        return head;
    }
 
    public void add(Node node){
        tail.next = node;
        tail = node;
    }
 
    public static class Node{
        private Node next;
        private String data;
 
        public Node(String data){
            this.data = data;
        }
 
        public String data() {
            return data;
        }
 
        public void setData(String data) {
            this.data = data;
        }
 
        public Node next() {
            return next;
        }
 
        public void setNext(Node next) {
            this.next = next;
        }
 
        public String toString(){
            return this.data;
        }
    }
}

Output

Length of LinkedList : 5
Middle Element of LinkedList : Orange

Write a Java program to find the middle element of a singly linked list in one pass

Source Code

Output

Example Programs

LinkedList Programs in Java