We need to decide on a directory structure. There is a proposal by @drkennetz that we separate challenges from solutions

from Slack

Format could be:

./CodingDojo/questions/
    ./03-26-2021/question.MD
    ./04-02-2021/question.MD./CodingDojo/answers/
    ./03-26-2021/answer.py, answer.js, answer.java, answer.rb
./CodingDojo/answers/
    ./03-26-2021/answer.py, answer.js, answer.java, answer.rb

(edited to properly display format)

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Sum of Squares

Language

Java

Approach

Check out some of our Java-based challenges for an IDE-agnostic unit-testing setup, or use the tools built in to your favorite IDE.

Longest Peak

Write a function that takes in an array of integers and returns the length of the longest peak in the array.

A peak is defined as adjacent integers in the array that are strictly increasing until they reach a tip (the highest value in the peak), at which point they become strictly decreasing. At least three integers are required to form a peak.

I will make this abundantly clear in the examples.

Business Rules/Errata

1. A peak must increase and then decrease.
2. The input can be an empty array, and must be an array of integers.
3. If equal value numbers appear in the run of a peak, the peak is stopped and restarted.
4. A peak must contain at least 3 numbers, such as 1,2,1
5. Numbers can be positive or negative.
6. Bonus: Optimal time and space: O(n) time | O(1) space - where n is the length of the input array.

Examples

longest_peak([5, 4, 3, 2, 1]) -> 0 # all decreasing
longest_peak([1, 2, 3, 4, 5]) -> 0 # all increasing
longest_peak([5, 4, 3, 2, 1, 2, 10, 12]) -> 0 # all decreasing, then all increasing
longest_peak([]) -> 0 # empty input check mandatory :D
longest_peak([1, 3, 2]) -> 3 # normal peak
longest_peak([1, 2, 3, 4, 5, 1]) -> 6 # peak ends on last number
longest_peak([2,2,3,2]) -> 3 # repeat at the beginning
longest_peak([1, 2, 3, 2, 1, 1]) -> 5 # repeat at the end
longest_peak([1, 2, 3, 3, 2, 1]) -> 0 # equality at peak tip, 0 is returned
longest_peak([1, 1, 1, 2, 3, 10, 12, -3, 2, 3, 45, 800, 99, 98, 0, -1, 2, 3, 4, 5, 0, -1]) -> 9 # peak in the middle -3, 2, 3, 45, 800, 99, 98, 0, -1

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Simple 2D Iterator

Language

Lots of Java in the repo already, add some more! Solve this challenge using Java.

Approach

Check out some of our Java-based challenges for an IDE-agnostic unit-testing setup, or use the tools built in to your favorite IDE.

Language

What language was used for the solution? I used Java

Challenge

What is the name of the challenge being completed? Sum of Squares

Uploading the Screenshot for the outputs of some test cases.

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Sum Arrays

Language

This challenge was originally set up for Ruby, but it looks like a Ruby solution was never submitted! Yikes! Solve this challenge in Ruby and fix that oversight for us, please.

Approach

Use the original unit tests!

To help with people learning about our repository through Hacktoberfest, we should include a link to the meetup page for people to join us in the future.

Sum Arrays

Given an array of values, return the sum of the values.

Business Rules/Errata

• Input must be an array.
• The array may be nested more than one level.
• All values must be integers.
• Solutions shall not use built in methods to flatten the array to one-dimension.

Examples

One dimension:

sum_of_array([1,2,3,4,5]) => 15

Two dimensions:

sum_of_array([1,2,[1,2,3],4,5]) => 18

n dimensions:

sum_of_array([1,[1,2,[3,4],5],[6,7]]) => 29

Simple 2D Iterator

Implement a class (or struct, or object) representing a 2-dimensional iterator. This class should be initialized with a 2-dimensional (nested) array, and should implement two methods:

• next() returns the next element in the array of arrays
• has_next() returns true/false indicating whether the iterator still has elements left

Business Rules/Errata

• Data Structure Required: 2D Array
• Your class will need a constructor method (or other strategy) to accept a 2-dimensional array and produce an instance of your class.
• You should not flatten or otherwise copy data out of the 2D array into another data structure.
• If you call next() on your class, and there are no elements left to return, return null (or some other indicator that the iterator has been exhausted).

Examples

Example 1

instance = new NestedIterator([[1, 2], [3], [], [4, 5, 6]]);
instance.next()  // 1
instance.next()  // 2
instance.next()  // 3
instance.has_next()  // true
instance.next()  // 4
instance.next()  // 5
instance.next()  // 6
instance.has_next()  // false
instance.next()  // NULL

Example 2

instance = new NestedIterator([[9], [1, 7, 5], [2, 9], []]);
instance.next()  // 9
instance.next()  // 1
instance.next()  // 7
instance.has_next()  // true
instance.next()  // 5
instance.next()  // 6
instance.next()  // 9
instance.has_next()  // false
instance.next()  // NULL

Discussion has been going around as to how we handle the flow of week to week tasks in preparation for the next mob session.

Challenges

Challenges will be submitted as issues. Voting on these (👍) should be restricted to one vote per person each week.

Challenge will be posted on Friday (Monday may be tried as well) for the following week.

Solutions

• No solutions will be accepted in PR before the mob/meetup.
• The mob solution will be titled mob.[lang] in the solutions directory for that challenge.
• Solutions may be submitted by anyone after that solution is merged. Any and all solutions of this type will be named with the person's github username and the lang. My solutions will be submitted as xanderyzwich.py if they are in Python. These solutions will be submitted through Pull Request (PR) from the persons fork of the repository. Code reviewers can/will assist with forming the solution such that it can be understood by others and be displayed for learning purposes.

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Pascal's Triangle

Language

Name of the language being requested. Choose from the list below:

Python

Language

What language was used for the solution? --> JAVA

Challenge

What is the name of the challenge being completed? --> Maximum Non-Adjacent Number Sum

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Issue Resolved

If there isn't an issue open that you are interested in then take a look in the Challenges directory for a challenge that you would like to solve.

Challenge

Any of the challenges that are posted are up for your contribution, regardless of whether or not there is an open issue for it.

Language

We do prefer that you solve the challenge in a language that hasn't been completed yet so that others can use the solutions for learning the differences in languages.

Approach

Using a language that has a previously submitted solutions is acceptable if you are using a different approach or algorithm. If you are going to submit a solution on basis of being a new approach, it is most helpful if you can implement both your new approach and the 'standard' approach and demonstrate how they are different based on things like runtime and space usage.

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Simple DB

Language

Go

This challenge requires tests in the form:

...
func UnsetTest(t *testing.T) {}
func RollbackTest(t *testing.T) {}
func NestedCommitTest(t *testing.T){}
...

For a reference of the test cases required, visit line 50 of the original solution.py

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Skip Counting

Language

JavaScript/TypeScript

Approach

Make sure to include tests to prove your solution is correct. Check out any of our other JS-based challenges to see how. (Example: Search Party)

Participation

All Hacktoberfest solutions should be provably correct. That is, solution submissions should either include the unit tests from the original challenge (implemented in your language of choice) or at least print out the expected answers when run by the maintainers. Solutions that do not meet these criteria may be rejected, or flagged as 'invalid' or 'spam' in egregious cases. This can result in your PR not counting towards your Hacktoberfest participation or becoming ineligible to participate in Hacktoberfest. Violations of our Code of Conduct will be reported, and will also render you ineligible to participate in Hacktoberfest. Please be respectful of the maintainers' and other participants' time by doing your best to submit real solutions to the puzzles. Thanks, and welcome to our learning community!

Challenge

Pragmatic Pipes

Language

Python

Approach

The solution to this one needs to include the tests, run when the script is invoked. For example:

import unittest

class TestStringMethods(unittest.TestCase):

    def test_one(self):
        input = pipe_graph(("S", []))
        result = input.minimum_spanning_tree("S")
        self.assertEqual(result, 0)


if __name__ == '__main__':
    unittest.main()