19. Remove Nth Node From End of List

class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
       ListNode curr = head;
       ListNode prev = null;
       ListNode next = curr.next;
        
        while(curr != null){
            curr.next = prev;
            prev = curr;
            curr = next;
            
            if(next != null){
                next = next.next;
            }
        }
        head = prev;
        ListNode temp = head;
        // while(temp != null){
        //     System.out.println(temp.val);
        //     temp = temp.next;
        // }
        //  return head;  
        if(head.next == null && n==1){
            head  = null;
            return head;
        }
        if( n == 1){
            head = head.next;
             curr = head;
        prev = null;
        next = curr.next;
        
        while(curr != null){
            curr.next = prev;
            prev = curr;
            curr = next;
            
            if(next != null){
                next = next.next;
            }
        }
        head = prev;
        return head;
        }
        for(int i=0;i<n-2;i++){
            temp = temp.next;
        }
        ListNode temp1 = temp.next.next;
        temp.next = temp1;
        
        curr = head;
        prev = null;
        next = curr.next;
        
        while(curr != null){
            curr.next = prev;
            prev = curr;
            curr = next;
            
            if(next != null){
                next = next.next;
            }
        }
        head = prev;
        return head;
        
    }
}