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https://github.com/garfield1002/jrsl

A C/C++ implementation of William Pugh's Skip Lists with width
https://github.com/garfield1002/jrsl

c c89 cpp library public-domain single-header-lib skiplist

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A C/C++ implementation of William Pugh's Skip Lists with width

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README 

        
# C/C++ Skip List Implementation



This is C89 implementation of the data type described in [William Pugh's paper](https:www.epaperpress.com/sortsearch/download/skiplist.pdf) with widths.



> Skip lists are a data structure that can be used in place of balanced trees.

> Skip lists use probabilistic balancing rather than strictly enforced balancing

> and as a result the algorithms for insertion and deletion in skip lists are

> much simpler and significantly faster than equivalent algorithms for

> balanced trees.



Using widths allows for efficient random access.



Although this library will work with C and C++, if you perfer fancy C++ objects you can check out [my first implementation of skip lists](https://github.com/Garfield1002/jhr_skip_list)



## 💡 Why use Skip Lists ?



Skip Lists allow insertion, deletion, random access and search in O(log n) on average (and O(n) in worst case).

Skip lists are a simple data structure that can be used in place of balanced trees for most applications and are much less daunting.



## 📚 Usage



**This library is written in standard C89 for portability.**



The idea behind single-header file libraries is that they're easy to distribute and deploy because all the code is contained in a single file.

The .h file acts as its own header files, i.e. it declares the functions and classes contained in the file but no code is getting compiled.



So in addition, you should select _exactly_ one C/C++ source file that actually instantiates the code, preferably a file you're not editing frequently.

This file should define `JRSL_IMPLEMENTATION` to actually enable the function definitions.



You can check out [example.c](https://github.com/Garfield1002/jrsl/blob/master/example/example.c) for some sample code.



### Skip List Methods



---



  

    Function

    Effect

  

  

    

        Creation and deletion

    

  

  

    jrsl_initialize()

    Initializes a skip list

  

  

  

    jrsl_destroy()

    Cleans up a skip list

  

  

    

        Size and capacity

    

  

  

    jrsl_max_level()

    Calculates the optimal maximum for the amount of levels

  

  

    

        Element access

    

  

  

    jrsl_data_at()

    Returns the data at a particular index

  

  

    

    jrsl_key_at()

    Returns the key at a particular index

  

  

    

        Modification

    

  

  

    jrsl_insert()

    Inserts an element (a key and some data) in the skip list and returns `NULL`

  

  

  

    jrsl_remove()

    Removes an element from the skip list, deletes the key and returns it's data

  

  

    

        Searching

    

  

  

    jrsl_search()

    Returns the data of the node with a given key

  

  

    

        Visualization

    

  

  

    jrsl_display_list()

    Prints a visual representation of the skip list

  



## ⭐ Contribution



All contributions are welcome!



## ⚖ License



This library is in the public domain. You can do anything you want with it. You have no legal obligation to do anything else, although I appreciate attribution.



It is also licensed under the MIT open source license, if you have lawyers who are unhappy with public domain. The source file includes an explicit dual-license for you to choose from.