Middle of the Linked List

Overview

Easy 2 solutions

Categories

Linked ListTwo Pointers

package linked_list.iterative;

import linked_list.ListNode;

public class MiddleOfTheLinkedList {

    public ListNode middleNode(ListNode head) {

        ListNode slow = head, fast = head;

        while (fast != null && fast.next != null) {
            fast = fast.next.next;
            slow = slow.next;
        }

        return slow;
    }

}

package com.eureka
package linked_list.recursive

import linked_list.ListNode

import scala.annotation.tailrec

object MiddleOfTheLinkedList:

  def middleNode(head: ListNode): ListNode =
    @tailrec def loop(slow: ListNode, fast: ListNode): ListNode =
      if fast == null || fast.next == null then slow else loop(slow.next, fast.next.next)
    loop(head, head)