Middle of the Linked List

Given the head of a singly linked list, return the middle node of the linked list.

If there are two middle nodes, return the second middle node.

Example 1:

Input: head = [1,2,3,4,5]
Output: [3,4,5]
Explanation: The middle node of the list is node 3.

Example 2:

Input: head = [1,2,3,4,5,6]
Output: [4,5,6]
Explanation: Since the list has two middle nodes with values 3 and 4, we return the second one.

Constraints:

• The number of nodes in the list is in the range [1, 100].

• 1 <= Node.val <= 100

Solutions:

Language: Java

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution 
{
    public ListNode middleNode(ListNode head) 
    {
        int len=0 ;
        ListNode temp = head ;
        // calculate the length of the linked list
        while(temp!=null)
        {
            temp = temp.next ;
            len++ ;
        }
        // finding middle of linked list
        len = len / 2 ;
         ListNode currentNode = head ;
         // iterate till length of linked list becomes 0
         while(len>0)
         {
             currentNode = currentNode.next; //shifting head forward
             len--; //reducing length
         }
           return currentNode ;  //node at which length becomes 0, is middle node

    }
}