* DPLL algorithm

* Corrections complete

* Formatting

* Codespell hook

* Corrections part 2

* Corrections v2

* Corrections v3

* Update and rename dpll.py to davis–putnam–logemann–loveland.py
Co-authored-by: NChristian Clauss <cclauss@me.com>

- update naming style to snake_case
- add type hints

* Add project euler problem 50

* Apply format changes

* Descriptive function/parameter name and type hints
Co-authored-by: NDhruv Manilawala <dhruvmanila@gmail.com>

* #3847 fix handling of non-ASCII characters in swap_case

* #3847 remove unused regex

* Fix formatting (with black) Fixes: #3847

* Add type hints for `swap_case` function
Co-authored-by: NFrank Schmitt <frankschmitt@gmx.de>
Co-authored-by: NDhruv Manilawala <dhruvmanila@gmail.com>

Name: Prime square remainders

Let pn be the nth prime: 2, 3, 5, 7, 11, ..., and
let r be the remainder when (pn−1)^n + (pn+1)^n is divided by pn^2.

For example, when n = 3, p3 = 5, and 43 + 63 = 280 ≡ 5 mod 25.
The least value of n for which the remainder first exceeds 10^9 is 7037.

Find the least value of n for which the remainder first exceeds 10^10.

Reference: https://projecteuler.net/problem=123

reference: #2695
Co-authored-by: NRavi Kandasamy Sundaram <rkandasamysundaram@luxoft.com>

* Added solution to Euler 64.

Added Python solution to Project Euler Problem 64.
Added a folder problem_064.
Added __init__.py file.
Added sol1.py file.

* Update sol1.py

Made formatting changes as mentioned by pre-commit

* Update sol1.py

Minor changes to variable naming and function calling as mentioned by @ruppysuppy

* Update sol1.py

Changes to function call as mentioned by @cclauss

* Added a solution for Project Euler Problem 203 (https://projecteuler.net/problem=203)

* Simplified loop that calculates the coefficients of the Pascal's Triangle. Changes based on review suggestion.

* Moved get_squared_primes_to_use function outside the get_squarefree function and fixed a failing doctest with the former.

* kth order statistics divide and conquer algorithm

* add explanation of algorithm.

* fix PEP8 line too long error

* update order to be compliant to isort

* add doctest

* make file black compliant

* Readd Project Euler 206 solution for issue #2695, dupe of pull request #3042

* Add PE 206 to directory

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

* add test to infix_to_postfix_conversion

* fixed pre-commit error

* fixed build error

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

* Add solution to problem 74

* Fix typo

* Edit unnecessary comment

* Rename folder, add default params in solution()

* Rename file to solve conflicts

* Fix doctests

* Added solution to Project Euler problem 301

* Added newline to end of file

* Fixed formatting and tests

* Changed lossCount to loss_count

* Fixed default parameter value for solution

* Removed helper function and modified print stmt

* Fixed code formatting

* Optimized solution from O(n^2) to O(1) constant time

* Update sol1.py

* Add files via upload

* Delete decimal_isolate.py

* Added decimal_isolate file.

* Update decimal_isolate.py

* Update decimal_isolate.py

* Update decimal_isolate.py

* Update decimal_isolate.py

* Update decimal_isolate.py

* Delete decimal_isolate.py

* Add files via upload

* Update maths/decimal_isolate.py
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Update decimal_isolate.py

* Update decimal_isolate.py

* Update decimal_isolate.py

* Update decimal_isolate.py
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Simplify GitHub Actions

* Update stale.yml
Co-authored-by: NChristian Clauss <cclauss@me.com>

* Fixed balanced_parentheses.py

* fixed pre-commit

* eliminate is_paired

* remove unused line

* updating DIRECTORY.md

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

* Add more test cases

* Update data_structures/stacks/balanced_parentheses.py
Co-authored-by: NChristian Clauss <cclauss@me.com>
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: NChristian Clauss <cclauss@me.com>

* add type hints to math/gcd

* add doctest

* math/gcd - run black formatter

* math/gcd: remove manual doctest

* add correction to gcd of negative numbers

* add more doctest in iterative gcd

* add solution to Project Euler problem 206

* Add solution to Project Euler problem 205

* updating DIRECTORY.md

* updating DIRECTORY.md

* Revert "Add solution to Project Euler problem 205"

This reverts commit 64e3d36cab2b68630b73a217c9ba455202d85cbb.

* Revert "add solution to Project Euler problem 206"

This reverts commit 53568cf4efd84f4b1c039eade335655842fa29e3.

* add solution for project euler problem 207

* updating DIRECTORY.md

* add type hint for output of helper function

* Correct default parameter value in solution

* use descriptive variable names and remove problem solution from doctest Fixes: #2695
Co-authored-by: Nnico <esistegal-aber@gmx.de>
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>

* Added solution for Project Euler problem 87. Fixes: #2695

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

* adding doctest to radix_sort.py file

* fixup! Format Python code with psf/black push

* Update radix_sort.py

* Update radix_sort.py

* fixup! Format Python code with psf/black push

* Update radix_sort.py

* line

* fix tests
Co-authored-by: Ngithub-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: NJohn Law <johnlaw.po@gmail.com>

* Added solution to problem 58

* Update sol1.py
Co-authored-by: NJohn Law <johnlaw.po@gmail.com>

* 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>