* Implement the melkman anlgorithm for computing convex hulls

* Link melkman algorithm description

* Format melkman algorithm code

* Add type hints to functions

* Fix build errors

* Added IBM Qiskit References

* space
Co-authored-by: NJohn Law <johnlaw.po@gmail.com>

- update naming style to snake_case
- add type hints

* Added reverse_letters.py

* Update strings/reverse_letters.py
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>

* Fix Project Euler Readme

* updating DIRECTORY.md

* Update CONTRIBUTING.md

* spacing
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Signed-off-by: NGaurav Chaudhari <capristar02@gmail.com>

* Made improvements to combinations.py

* Update maths/combinations.py
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>

* Function now raises an error when given invalid input

* Update maths/combinations.py
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>

* Update CONTRIBUTING.md

Needed to tell people so we do not receive any duplicate solution. Do not count this as hactoberfest-accepted

* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

typo fix
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>

* Update CONTRIBUTING.md
Co-authored-by: Du Yuanchao <shellhub.me@gmail.com>
Co-authored-by: NJohn Law <johnlaw.po@gmail.com>

* Update lucas_series.py

Added another method to calculate lucas_numbers

* Fix pre-commit error

* Update lucas_series.py

* Update lucas_series.py

* Update lucas_series.py

* Update lucas_series.py

* Update ceil and floor function

* add end line

* updating DIRECTORY.md
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* Add single bit manipuation operations.

* fixup! Add single bit manipuation operations.

* Change wording.

* Add solution to problem 81 - project euler

* Update project_euler/problem_081/sol1.py
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Update project_euler/problem_081/sol1.py
Co-authored-by: NChristian Clauss <cclauss@me.com>
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Fix style of the first ten solutions for Project Euler

- Unify the header docstring, and add reference URLs to wikipedia
  or similar
- Fix docstrings to be properly multilined
- Add newlines where appropriate
- Add doctests where they were missing
- Remove doctests that test for the correct solution
- fix obvious spelling or grammar mistakes in comments and
  exception messages
- Fix line endings to be UNIX. This makes two of the files seem
  to have changed completely
- no functional changes in any of the solutions were done
  (except for the spelling fixes mentioned above)

* Fix docstrings and main function as per Style Guide

* Add 0-1-bfs.

* fixup! Add 0-1-bfs.

* fixup! Add 0-1-bfs.

* Check edge weights.

* Check edge vertecies.

* add forecasting code

* add statsmodel

* sort import

* sort import fix

* fixing black

* sort requirement

* optimize code

* try with limited data

* sort again

* sort fix

* sort fix

* delete warning and black

* add code for forecasting

* use black

* add more hints to describe

* add doctest

* finding whitespace

* fixing doctest

* delete

* revert back

* revert back

* revert back again

* revert back again

* revert back again

* try trimming whitespace

* try adding doctypeand etc

* fixing reviews

* deleting all the space

* fixing the build

* delete x

* add description for safety checker

* deleting subscription integer

* fix docthint

* make def to use function parameters and return values

* make def to use function parameters and return values

* type hints on data safety checker

* optimize code

* Update run.py
Co-authored-by: NFVFYK3GEHV22 <fvfyk3gehv22@FVFYK3GEHV22s-MacBook-Pro.local>
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Move PE validate_solutions to scripts/ directory

* Update pytest.ini file with durations settings

* Remove codespell and autoblack workflow file

* Dependent changes to test config files

* Update pytest.ini

* update LinkedQueue

* add type hint and rename

* Added solution for Project Euler problem 38. Fixes: #2695

* Update docstring and 0-padding in directory name. Reference: #3256

* Renamed is_9_palindromic to is_9_pandigital.

* Changed just-in-case return value for solution() to None.

* Moved exmplanation to module-level docstring and deleted unnecessary import

* Add solution for Project Euler 65,

* Add URL to problem 65 and don't pass in parameter to solution()

* Remove solution() tests

* Add tests for solution(), add fstring and positional arg for solution

* Rename directory and problem number to 065

* Remove directory

* Move up explanation to module code block

* Move solution() below helper function, rename variables

* Removed unused variable m.

* Doctests are modified to match functions.

* Added condition for negative values.

* Fixed white-space around operator.

* Fixed W293 blank line contains white-space error.

* Update dynamic_programming/coin_change.py
Co-authored-by: NTapajyoti Bose <44058757+ruppysuppy@users.noreply.github.com>

* Fixed error in code.

* Fixed whited spacing.

* Fixed PEP8 error.

* Added more test cases for coin change problem.

* Removed extra test for negetive value.
Co-authored-by: NTapajyoti Bose <44058757+ruppysuppy@users.noreply.github.com>

* Made small improvements and shortened prime_check.py

* improved descriptions on tests in prime_check.py

* Ran black and isort

* update linked_stack

* remove properties

* updating DIRECTORY.md
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* update doubly linked list

* reformat code
add more test

* add test to iter

* updating DIRECTORY.md
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* Upgrade to Python 3.8 syntax

* updating DIRECTORY.md
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* Create medianOf TwoArrays.py

This code finds the median of two arrays (which may or may not be sorted initially).
Example: 
Enter elements of an array: 1 5 4 2
Enter elements of another array: 1 7 4 2 7
The median of two arrays is :  4

* Rename medianOf TwoArrays.py to median_of _two_arrays.py

* Rename median_of _two_arrays.py to median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Update median_of_two_arrays.py

* Add naive recursive implementation of 0-1 Knapsack problem

* Fix shadowing

* Add doctest

* Fix type hints

* Add link to wiki

* Blacked the file

* Fix isort

* Move knapsack / add readme and more tests

* Add missed main in tests

* Add Patience Sort

* fix code for pre-commit

* Fix params def

* Adding new line at end of file

* Remove Trailing Whitespace

* Adding space between the methods of the Stack class

* Removing Trailing Whitespace

* Ordering Imports

* Adding url patience sort
Co-authored-by: Njvnascimento <nascimento783@gmail.com>

* Fix broken build: Remove trailing spaces

* updating DIRECTORY.md

* One more trailing space
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* Implement Deutsch-Jozsa Algorithm In Qiskit
Signed-off-by: NAbhishek Jaisingh <abhi2254015@gmail.com>

* Add Changes Requested In Review
Signed-off-by: NAbhishek Jaisingh <abhi2254015@gmail.com>

* Address Further Review Comments

* fixup! Format Python code with psf/black push
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* create monoalphabetic cipher

* update file

* update file

* update file

* update file

* update file

* update after testing flake8 on this code

* update file

* update file

* update file

* update file

* update file

* update file

* create beaufort cipher

if you like my code, merge it and add the label as `hacktoberfest-accepted`

* update the file

* Update beaufort_cipher.py

* Update beaufort_cipher.py

* update as per black formatter

* Update beaufort_cipher.py

* update the file

* update file

* update file

* update file

* update file

* Fix the build -- 88 chars per line max.

* updating DIRECTORY.md
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* Fixed typo in caesar_cipher.py

* Typo fixes

* Qiskit: Add Quantum Half Adder

* fixup! Format Python code with psf/black push
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

With this set, Windows users will have text files converted from Windows style line endings (\r\n) to Unix style line endings (\n) when they’re added to the repository.
https://www.edwardthomson.com/blog/git_for_windows_line_endings.html

* Add GitHub action for Project Euler only

* Add second job for Project Euler

* Remove Project Euler jobs from Travis CI

* Fix typo for actions/setup-python

* Rename the workflow file

* Change name of file in workflow

* Remove comments from Travis config file

* Create evaluate_postfix_notations.py

Adding in the evaluate postfix notation using Stacks
one of the common use with simple stack question
creating a new file for the data structure of stacks

* Create evaluate_postfix_notations.py

Adding in the evaluate postfix notation using Stacks
one of the common use with simple stack question
creating a new file for the data structure of stacks

* Delete evaluate_postfix_notations.py

* Evaluate postfix expression stack clean approach

Sending in the PR again as the Previous request failed in pre commit

* Update evaluate_postfix_notations.py

* Update evaluate_postfix_notations.py

Made changes as per the required for fixing the failing pre-commits.

* Update evaluate_postfix_notations.py

Made changes as suggested by @cclauss

* Update evaluate_postfix_notations.py

fixed pre-commit fails

* Update evaluate_postfix_notations.py

fixing pre-commit fails

* Update evaluate_postfix_notations.py

Deleted trailing white spaces causing pre-commits to fail

* Update data_structures/stacks/evaluate_postfix_notations.py
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Update data_structures/stacks/evaluate_postfix_notations.py
Co-authored-by: NChristian Clauss <cclauss@me.com>
Co-authored-by: NChristian Clauss <cclauss@me.com>