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

ListNode(int val) {
    this.val = val;
}

}/ import java.util.; public class Solution { public ListNode ReverseList(ListNode head) { if(head==null) return null; List list=new ArrayList<>(); ListNode node=head; while(node!=null){ list.add(node.val); node=node.next; } ListNode listNode = head; for (int i = list.size()-1; i >=0 ; i--) { listNode.val=list.get(i); listNode=listNode.next; } return head; } }