public static void reverseIterative(_<ListNode> list){
if( list.value() == null)
return ;
ListNode prev = null ;
ListNode curr = list.value() ;
while( curr!=null){
ListNode next = curr.next ;
curr.next = prev ;
prev = curr ;
curr = next ;
}
list.set(prev);
}
public static void reverseRecursive(_<ListNode> list){
if( list.value() == null )
return ;
ListNode head = list.value();
ListNode rest = head.next ;
if(rest==null) // a singular list
return ;
_<ListNode> reversed = new _<ListNode>(rest);
reverseRecursive( reversed );
head.next.next = head ;
head.next = null ;
list.set(reversed.value());
}
public static void createEvenLengthList(_<ListNode> head, _<ListNode> front, _<ListNode> tail){
ListNode list = new ListNode(6);
list.next = new ListNode(5);
list.next.next = new ListNode(4);
list.next.next.next = new ListNode(3);
head.set(list);
ListNode frontList = new ListNode(6);
frontList.next = new ListNode(5);
front.set(frontList);
ListNode tailList = new ListNode(4);
tailList.next = new ListNode(3);
tail.set(tailList);
}