skip-lists

I've been reading about Skip Lists lately. I have a web application that executes quite complex Sql queries against static datasets. I want to implement a caching system whereby I generate an md5 hash of the sql query and then return a cached dataset for the query if it exists in the collection. Which algorithm would be better, Dictionary or a SkipList? Why? http://msdn.microsoft.com/en-us/library/ms379573%28VS.80%29.aspx#datastructures20_4_topic4 Dictionary , definitely. Two reasons: Dictionary<TKey, TValue> uses a hash table, making retrieval O(1) (i.e. constant time), compared to O(log n )

I find ConcurrentSkipListSet in Java Collection Framework, which is backed up with a skip list. But is there a skip list in Java? A set does not work in my use case. I need a indexable list that supports duplicates. Since you've mentioned a List that is both Indexable (I assume you want speedy retrieval) and need to allow duplicates, I would advise you go for a custom Set with a LinkedList or ArrayList perhaps. You need to have a base Set, an HashSet for example and keep adding values to it. If you face a duplicate, the value of that Set should point to a List. So, that you will have both

I'm trying to implement a skip list that perform as good as a BST using a minimum additional memory overhead, at the moment even not considering any memory restriction the performance of my SkipList implementation is far away from even a very naive Balanced BST implementation -so to say, handcrafted BTS :) - As reference I'm using the original paper from William Pugh PUG89 and the implementation i found in Algorithms in C from Sedgewick -13.5-. My code is a recursive implementation, here's the clue of the insert and find operation: sl_node* create_node() { short lvl {1}; while((dist2(en)<p)&&

I'm wondering whether anyone here has ever used a skip list . It looks to have roughly the same advantages as a balanced binary tree but is simpler to implement. If you have, did you write your own, or use a pre-written library (and if so, what was its name)? Todd Years ago I implemented my own for a probabilistic algorithms class. I'm not aware of any library implementations, but it's been a long time. It is pretty simple to implement. As I recall they had some really nice properties for large data sets and avoided some of the problems of rebalancing. I think the implementation is also

I need to implement a lock-free skip list. I tried to look for papers. Unfortunatly all I found was lock-free single linked lists (in many flavors). However how to implement lock-free skip list? ire_and_curses Lock-free skip lists are described in the book The Art of Multiprocessor Programming , and the technical report Practical lock-freedom , which is based on a PhD thesis on the subject. The skip list discussion begins on page 53. An example implementation, based on these sources, is included in this google code project . There are related discussions, links to literature and

The redis documentation for ZADD states the operation is O(log N ). However, does anyone know if ZADD is better than O(log N ) when the inserted element is at the beginning or end of the sort order? E.g. for certain implementations this could be O(1). Specifically, the redis tutorial states that: Sorted sets are implemented via a dual-ported data structure containing both a skip list and an hash table, so every time we add an element Redis performs an O(log( N )) operation. It seems plausible to modify a skip list to support O( k ) insert at beginning and end, where k is the max level of the

In some blogs and lucene website,I know lucene use data structure "skip list" in inverted index. But I have some puzzle about it. 1:In general,skip list maybe used in memory ,but inverted index is stored in disk. So how lucene use it when search on the index? just scanning it on disk or load it to memory? 2:skip list's insert operator often use random(0,1) to decide whether insert to next level,but in luncene introdution,it seems a fixed interval in every terms,so how lucene create the "skip list" different or not? Please correct me if I am wrong. Lucene uses memory in a couple different ways,