I would suggest you to use variable names with some meaning. Your names like k
, v
are terrible to understand
Instead of firstNode =k;
should be firstNode.next =k;
but it's better to rewrite with proper names. Like this
DListNode next=firstNode.next;
DListNode newOne=new DListNode(e,next,firstNode);
firstNode.next =newOne;
next.prev=newOne;