You would only be able to re-link node1 to node 4, but node 2 and node
3 would be orphaned and inaccessible. If no pointers lead to those
nodes, you cannot access them to fix their links.
On Aug 31, 11:49 am, Dheeraj Sharma <dheerajsharma1...@gmail.com>
wrote:
> head -> node1 <-> node2 <- node3 <-> node4 -> node5 <-> node6 <->
> ^ missing right ^missing left
> node7 <- tail
>
> now head and tail are given..is there any way to fix the pointers again?
>
>
>
>
>
>
>
>
>
> On Wed, Aug 31, 2011 at 11:07 PM, Chris <lokr...@gmail.com> wrote:
> > Being a doubly linked list you should have a head and tail (kinda the
> > reason why you'd use a doubly linked list in the first place). If you
> > don't then I'm not sure how you'd fix that as the rest of the list
> > after the first missing right pointer would essentially be orphaned in
> > memory with no valid pointers allowing you to fix the rest of the
> > list.
>
> > head -> node1 <-> node2 -> node3 <-> node4 <- node5 <-> node6 <->
> > node7 <- tail
> > ^ missing left ^
> > missing right.
>
> > Given this example, using the forward traversing while loop you would
> > be able to fix the link between node2 and node3, but would end on
> > node4 without any way to fix the missing right pointer since nothing
> > would be able to access the rest of the list without a tail. And
> > without a tail pointer, we would not know that any nodes in memory
> > actually point back at node4 so we would just think that's the end of
> > the list... Short of scanning the entire heap to find some memory that
> > contains node4's address (somehow) that data is just inaccessible and
> > orphaned now.
>
> > On Aug 31, 10:44 am, Dheeraj Sharma <dheerajsharma1...@gmail.com>
> > wrote:
> > > i get more clear to my quest..
> > > 1.Doubly Linked List
> > > 2.Firstly some right pointer is missing....and lately..some left pointer
> > is
> > > missing
> > > 3.Head of pointer is given.
> > > 4.Repair the list..
>
> > > On Wed, Aug 31, 2011 at 10:12 PM, Sanjay Rajpal <srn...@gmail.com>
> > wrote:
> > > > Chris : he said first, right pointer is missing, how can u repair that
> > left
> > > > pointer first as you can't go forward ?
>
> > > > Sanju
> > > > :)
>
> > > > On Wed, Aug 31, 2011 at 9:39 AM, Chris <lokr...@gmail.com> wrote:
>
> > > >> When you say missing, I assume the left or right pointer is null. If
> > > >> that's the case, this could be a possible solution:
>
> > > >> // this fixes the missing left pointers traversing from the head
> > > >> node* curr = head;
> > > >> while (curr->right != null ) {
> > > >> if (curr->right->left == null) {
> > > >> curr->right->left = curr;
> > > >> }
> > > >> curr = curr->right;
> > > >> }
>
> > > >> // reverse the logic to fix pointers in the other direction starting
> > > >> at the end of the list
> > > >> node* curr = tail;
> > > >> while (curr->left != null) {
> > > >> if (curr->left->right == null) {
> > > >> curr->left->right = curr;
> > > >> }
> > > >> curr = curr->left;
> > > >> }
>
> > > >> On Aug 31, 10:23 am, Dheeraj Sharma <dheerajsharma1...@gmail.com>
> > > >> wrote:
> > > >> > A doubly linked list has one Left pointer missing and at some
> > > >> point..one
> > > >> > Right pointer missing..how to repair the doubly linked list?
> > > >> > ?
>
> > > >> > --
> > > >> > *Dheeraj Sharma*
> > > >> > Comp Engg.
> > > >> > NIT Kurukshetra
> > > >> > +91 8950264227
>
> > > >> --
>
> > > >> You received this message because you are subscribed to the Google
> > Groups
> > > >> "Algorithm Geeks" group.
> > > >> To post to this group, send email to algogeeks@googlegroups.com.
> > > >> To unsubscribe from this group, send email to
> > > >> algogeeks+unsubscr...@googlegroups.com.
> > > >> For more options, visit this group at
> > > >>http://groups.google.com/group/algogeeks?hl=en.
>
> > > > --
> > > > You received this message because you are subscribed to the Google
> > Groups
> > > > "Algorithm Geeks" group.
> > > > To post to this group, send email to algogeeks@googlegroups.com.
> > > > To unsubscribe from this group, send email to
> > > > algogeeks+unsubscr...@googlegroups.com.
> > > > For more options, visit this group at
> > > >http://groups.google.com/group/algogeeks?hl=en.
>
> > > --
> > > *Dheeraj Sharma*
> > > Comp Engg.
> > > NIT Kurukshetra
> > > +91 8950264227
>
> > --
> > You received this message because you are subscribed to the Google Groups
> > "Algorithm Geeks" group.
> > To post to this group, send email to algogeeks@googlegroups.com.
> > To unsubscribe from this group, send email to
> > algogeeks+unsubscr...@googlegroups.com.
> > For more options, visit this group at
> >http://groups.google.com/group/algogeeks?hl=en.
>
> --
> *Dheeraj Sharma*
> Comp Engg.
> NIT Kurukshetra
> +91 8950264227
--
You received this message because you are subscribed to the Google Groups
"Algorithm Geeks" group.
To post to this group, send email to algogeeks@googlegroups.com.
To unsubscribe from this group, send email to
algogeeks+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/algogeeks?hl=en.
