Python Algorithms

Python Algorithms contains a collection of useful algorithms written in python. The algorithms include (but not limited to) topics such as searching, sorting, graph, and string theory.

This project is inspired from the textbook Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne and associated book-site http://algs4.cs.princeton.edu/home/. The goal of this book is summarized in the following excerpt from the book-site:

Our original goal for this book was to cover the 50 algorithms that every programmer should know. We use the word programmer to refer to anyone engaged in trying to accomplish something with the help of a computer, including scientists, engineers, and applications developers, not to mention college students in science, engineering, and computer science.

However, the algorithms for this project are not meant to be a ported version of the algorithms found in the book. Efforts should be made to implement those algorithms from the scratch following Pythonic coding style. Some of the algorithms are well known and the reference for those algorithms should appear in the documentation. While, some of the algorithms are very specific and difficult implement in a different way while maintaining accuracy and efficiency. Such algorithms appear in the scientific literatures and/or books and those should be properly referenced as well.

Features

• Mainly for educational purposes, but can be useful in certain practical scenarios as well.
• Consequently, built-in algorithms are avoided as much as possible and detailed implementation is done from the scratch.
• Preference is given towards a pythonic style rather than sticking to true OOP style.
• Free software: BSD license.
• Documentation: http://python_algorithms.rtfd.org.

Algorithms

Here is a list of algorithms divided into packages.

Basic

A collection of few basic algorithms that do not fit in other packages. Trivial algorithms and data structures that are built into python are skipped.

• Binary search
• Knuth shuffle
• Stack
• Queue
• Bag
• Union find

Searching

Specialized searching algorithms and/or corresponding data structures are included in this package. Although some of the following data structures, such as Hash, are implemented in python, they have been implemented for demonstration purpose. Unless, specific needs arise, the built-in data structures should be preferred in production code.

• BST
• Red black BST
• Hash

Sorting

• Insertion
• Selection
• Merge
• Quick
• Quick 3 way
• Shell
• Heap

Graph

• Graph
• Directed graph
• BFS
• BFS paths
• DFS
• DFS paths
• Topological

String

• LSD
• MSD
• Quick 3 string
• TST
• KMP
• Rabin karp