What is a linked quad list?

advertisements

I'm currently working on implementing a list-type structure at work, and I need it to be crazy effective. In my search for effective data structures I stumbled across a patent for a quad liked list, and this sparked my interest enough to make me forget about my current task and start investigating the quad list instead. Unfortunately, internet was very secretive about the whole thing, and google didn't produce much in terms of usable results. The only explanation I got was the patent description that stated:

A quad linked data structure that provides bidirectional search capability for multiple related fields within a single record. The data base is searched by providing sets of pointers at intervals of N data entries to accommodate a binary search of the pointers followed by a linear search of the resultant range to locate an item of interest and its related field.

This, unfortunately, just makes me more puzzled, as I cannot wrap my head around the non-layman explanation. So therefore I turn to you all in hope that you can explain to me what this quad linked history really is, as I know not knowing will drive me up and over the walls pretty quickly.

Do you know what a quad linked list is?

I've not come across the term formally before, but from the patent description, I can make an educated guess.

A linked list is one where each node has a link to the next...

a -->-- b -->-- c -->-- d -->-- null

A doubly linked list means each node holds a link to its predecessor as well.

  --<--   --<--   --<--
|       |       |       |
a -->-- b -->-- c -->-- d -->-- null

Let's assume the list is sorted. If I want to perform binary search, I'd normally go half way down the list to find the middle node, then go into the appropriate interval and repeat. However, linked list traversal is always O(n) - I have to follow all the links. From the description, I think they're just adding additional links from a node to "skip" a fixed number of nodes ahead in the list. Something like...

  --<--   --<--   --<--
|       |       |       |
a -->-- b -->-- c -->-- d -->-- null
|                       |
|----------->-----------|
 -----------<-----------

Now I can traverse the list more rapidly, especially if I chose the extra link targets carefully (i.e. ensure they always go back/forward half of the offset of the item they point from in the list length). I then find the rough interval I want with these links, and use the normal links to find the item.

This is a good example of why I hate software patents. It's eminently obvious stuff, wrapped in florid prose to confuse people.

Related Articles

gcc linker get list of unused objects

I want to identify unused object files in a large C application with many libraries. The project has grown a lot over time and now I want to search for libraries that are not used anymore, so that I can remove them from the dependency file. Is it pos

What kind of queues are lists and dictionaries?

I'm just wondering what kind of queues are lists and dictionaries in C#. Whether they're FIFOs or LIFOs.Lists and dictionaries are containers that don't support a queue model, that is, they're neither LIFO nor FIFO. Put another way, you're not compar

What is Mysql Link?

I am debugging a php application. In the Local Debugging window, it shows the following information Name value Type LinkID 15 mysql link The value of LinkID change within the program What is mysql link type , being shown in the debugging window? Also

What is the difference between list and list [:] in python?

What, if any, is the difference between list and list[:] in python?When reading, list is a reference to the original list, and list[:] shallow-copies the list. When assigning, list (re)binds the name and list[:] slice-assigns, replacing what was prev

Ruby background: What are the linked lists?

I'm a self taught programmer and started off with Ruby. I'm currently trying to learn algorithms and data structures and noticed something called a linked list. It looks like Ruby doesn't have that data structure (maybe in Array?). I'm familiar with

What exactly is a doubly linked circular list? C ++

I have do to an assignment where we are to do a doubly linked list with no head or tail. I want to find examples of this very thing so I can understand it better. Now a Circular Doubly Linked List C++ is just that is it not? When I look up this in go

Creating a linked circular list

I haven't worked with linked lists in a long time, and I can't figure out why this code fails. I'm trying to create a very simple circular linked list with exactly 5 nodes. I will never need to insert additional nodes nor delete existing ones. I get

Removing a node from a linked LUT list?

We are trying to write a method to delete a node with a particular key from a linked list implementation of a LUT. Summary of the code I wrote: public void delete (String k) { Node currNode = listHead; Node prevNode = listHead; Key key = new Key (k);