/**

 * Definition for ListNode.

 * public class ListNode {

 *     int val;

 *     ListNode next;

 *

 *     ListNode(int val) {

 *         this.val = val;

 *         this.next = null;

 *     }

 * }

 */

public class Solution {

    /**

     * @param head: The head of linked list.

     * @return: The new head of reversed linked list.

     */

    public ListNode reverse(ListNode head) {

        ListNode preNode = null;

        ListNode nextNode;

        ListNode curNode = head;

        while(curNode != null){

            nextNode = curNode.next;

            curNode.next = preNode;

            preNode = curNode;

            curNode = nextNode;

        }

        return preNode;// write your code here

    }

}