19. Remove Nth Node From End of List

/*19. Remove Nth Node From End of List
Runtime: 0 ms, faster than 100.00% of Java online submissions for Remove Nth Node From End of List.
Memory Usage: 36.8 MB, less than 89.48% of Java online submissions for Remove Nth Node From End of List.


*
 * 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 removeNthFromEnd(ListNode head, int n) {
        ListNode dummy = new ListNode(0);
    dummy.next = head;
    ListNode first = dummy;
    ListNode second = dummy;
        
              
        
        
        for(int i=0;i<=n;i++)
            first=first.next;
        
        while(first!=null)
        {
            first=first.next;
            second=second.next;
        }
        
        
        second.next=second.next.next;
        return dummy.next;
        
    }
}