24, reversing a linked list

After entering a list inverted list, the new list of the output header.

Thinking: need to define three pointers, pointing to the currently traversed node, and its previous node to a node.

Test Case:

List head pointer (1) is a null input

List (2) only one input node

List (3) has a plurality of input nodes

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
        public ListNode ReverseList(ListNode head) {
        if(head == null || head.next == null)
            return head;
        ListNode newHead = null;
        ListNode curNode = head, prevNode = null;
        while(curNode != null){
            ListNode nextNode = curNode.next;
            if(nextNode == null)
                newHead = curNode;
            curNode.next = prevNode;
            prevNode = curNode;
            curNode = nextNode;
        }
        return newHead;
    }
}

Recursive solution for reversing the list:

    public ListNode ReverseList (ListNode head) {
          IF (head == null || head.next == null )
             return head; 
        
        // first inverting behind list, go to the end of the linked list node 
        ListNode pReverseNode = ReverseList (head.next ); 
         
        // then the current node as a node subsequent nodes behind 
        head.next.next = head; 
        head.next = null ;
         return pReverseNode; 
    }