Remove Nth Node From End of List

This is a cliche problem, all I have learned is don’t forget the corner case of head node in linkedlist problem!!!!!!!!!

Descrption

https://leetcode.com/problems/remove-nth-node-from-end-of-list/description/

Solution

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        if (head == null) return null; //corner case
        
        ListNode current = head, nextNNode = head;
        //Find the next n-th node
        while(nextNNode != null && n > 0) {
            nextNNode = nextNNode.next;
            n -= 1;
        }
        if (nextNNode == null) return head.next; //Remove the head
        
        //Traverse the remaining node
        while(nextNNode.next != null) {
            nextNNode = nextNNode.next;
            current = current.next;
        }
        current.next = current.next.next;
        return head;
    }
}