Wikipedia: Quicksort

coding-challenges

Continually updated Python Notebooks containing TDD-based coding challenges and solutions (algorithms and data structures).

Index

• Arrays and Strings
• Linked Lists
• Stacks and Queues
• Sorting and Searching
• Recursion and Dynamic Programming
• Trees and Graphs
• Bit Manipulation
• Scalability and Memory Limits
• Concurrency
• HackerRank and TopCoder
• Notebook Installation
• Credits
• Contributing
• Contact Info
• License

Arrays and Strings

Notebook	Problem Statement
unique_chars	Determine if a string contains unique characters
reverse_string	Reverse characters in a string
permutation	Determine if a string is a permutation of another
replace_char	Encode spaces in a string in-place
compress	Compress a string
rotation	Determine if a string is a rotation of another
hash-map	Implement a hash table with set, get, and remove methods

Linked Lists

Notebook	Problem Statement
remove_duplicates	Remove duplicates from a linked list
kth_to_last_elem	Find the kth to last element of a linked list
delete_mid	Delete a node in the middle of a linked list, given access to only that node
partition	Partition a linked list around a given value
add_reverse	Add two numbers whose digits are stored in a linked list in reverse order
find_loop_start	Find the start of a linked list loop
palindrome	Determine if a linked list is a palindrome
linked_list	Implement a linked list with insert, find, delete, and print methods

Stacks and Queues

Notebook	Problem Statement
n_stacks	Implement n stacks using a single array
stack_min	Implement a stack that keeps track of its minimum element
set_of_stacks	Implement a set of stacks class that wraps a list of stacks, each bound by a capacity
hanoi	Implement the Towers of Hanoi with 3 towers and N disks
queue_from_stacks	Implement a queue using two stacks
sort_stack	Sort a stack using another stack as a buffer
stack	Implement a stack with push, pop, and peek methods using a linked list
queue	Implement a queue with enqueue and dequeue methods using a linked list

Sorting and Searching

Notebook	Problem Statement
selection_sort	Implement selection sort
insertion_sort	Implement insertion sort
quick_sort	Implement quick sort
merge_sort	Implement merge sort

Recursion and Dynamic Programming

Notebook	Problem Statement
fibonacci	Implement fibonacci recursively, dynamically, and iteratively

Trees and Graphs

[Coming Soon]

Bit Manipulation

[Coming Soon]

Scalability and Memory Limits

[Coming Soon]

Concurrency

[Coming Soon]

HackerRank and TopCoder

Notebook	Problem Statement
utopian_tree	View problem statement on HackerRank
maximizing_xor	View problem statement on HackerRank

Notebook Installation

If you already have Python installed and are familiar with installing packages, you can get IPython with pip:

pip install ipython

Or if you want to also get the dependencies for the IPython notebook:

pip install "ipython[notebook]"

For more details on installation, follow the directions here.

To interact with or to modify elements within the IPython notebooks, you must first clone or download the repository then run the ipython notebook. More information on IPython Notebooks can be found here.

$ git clone https://github.com/donnemartin/coding-challenges.git
$ cd [downloaded repo directory name]
$ ipython notebook

Notebook tested with Python 2.7.x.

Credits

• Cracking the Coding Interview | GitHub
• Elements of Programming Interviews | GitHub
• Programming Interviews Exposed
• The Algorithm Design Manual | Selected Solutions
• CareerCup
• Quora
• HackerRank
• TopCoder

Contributing

Contributions are welcome!

For bug reports or requests please submit an issue.

For pull requests, please follow the general notebook format.

Contact Info

Feel free to contact me to discuss any issues, questions, or comments.

• Email: donne.martin@gmail.com
• Twitter: @donne_martin
• GitHub: donnemartin
• LinkedIn: donnemartin
• Website: donnemartin.com

License

Copyright 2015 Donne Martin

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.