CODE REVIEW 2017 Challenge

Question

I want to introduce the Community Oriented Development Extravaganza, Requiring Extreme Vigor Inciting Extraordinary Winners (or CODE REVIEW) 2017 Challenge. Traditionally our Community Challenges are non-competitive, this challenge aims to change that just a bit.

We usually have these challenges run for a month, and we announce them a month in advance except in certain situations where we want to boost participation. This time I'm going to run the announcement for three (3) months and run the challenge another three (3) months. At the end of the 6-month period, I will award a 500 reputation bounty to the winner of the challenge.

Major dates for the challenge are below:

• Thursday, 1 June 2017: Challenge begins accepting suggestions
• Thursday, 31 August 2017 23:59:59 UTC+0000: Challenge finishes accepting suggestions
• Friday, 1 September 2017 00:00:00 UTC+0000: Challenge begins
• Thursday, 30 November 2017 23:59:59 UTC+0000: Challenge ends
• Friday, 1 December 2017: Winner is announced from entries

How does one win?

In order to support the idea of a winner, we have to make sure that there is something to 'win'. Each challenge suggestion must have a detailed list of possible points to be awarded, and the participants are graded based on how many total points they earned (out of possible points).

The exact details of the awards will be announced later in the season, but at a minimum the following will be awarded:

• The first-place winner will receive a 500-reputation bounty;
• In the case of multiple first-place winners then each winner will receive a 250-reputation bounty;

If participation is high (left to the discretion of the members of the community who are offering the rewards) then an additional tiered reward system may be put in place.

How should suggestions differ from normal?

The only difference that suggestions require from traditional community-challenge questions is that they must detail specific features that require implementation and the total point-count for each feature. Challenge suggestions may mark features as 'optional' or 'required', and if a participant fails to implement all 'required' features then they are disqualified.

You may not reuse any previous community challenge selections as normally required, but you may re-suggestion un-selected challenges, and suggest challenges that are somewhat large in scope.

How does one enter as a participant?

A question with the entry requirements (also included below) and a list of all entries will be posted on Friday, 1 September 2017.

Participating is easy, and simply requires one to meet all criteria below:

• Complete all required portions of the selected challenge;
• Post the implementation of the challenge as a question on the main-site tagged community-challenge;
• Post an answer to the entry question posted here on meta;
• Include a link to the entry question in the answer to the entry form;

You may update your entry at any time (which means you may post iterative reviews as well), all entries will be judged at the end of the challenge season (Thursday, 30 November 2017). Entries may make as many revisions as possible, but the question linked in the entry form at 23:59:59 UTC+0000 on Thursday, 30 November 2017.

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Make sure you post the suggestions you have for this extravaganza in this question, the most upvoted answer at the end of the day on 31 August 2017 will become the challenge for this three-month extraordinaire!

Answer 1

Write your own programming language

I think for this challenge we should make the barrier to entry low, the barrier to win high, but most of all it should be fun!

Since we're writing a language, it's always good to know that it works. And so to score each point that adds additional features requires a unit test. All unit test must be provided for you to score the point. To allow all languages to do this, you can verify the programs output in the language you're writing in. And so if you were to write your language in the Python programming language having a unit test such as the following would be valid:

import unittest

class TestStandardArithmetic(unittest.TestCase):
    def test_addition(self):
        # Replace `eval` with how you run your code
        self.assertEqual(eval('1 + 1'), 2)

Requirements

• You won't be scored for any use of eval that's provided by your language. Posting input() as your language, and requiring Python 2 is a valid language, however will score you no points.

• When scoring each point, you must use your own implementation for that point to score the point. This allows you to use, say, the LLVM to implement tail recursion in your language by default, however when scoring the point for tail recursion, you have to use your own implementation of it rather than the one provided to you by the LLVM.

• Another person must be able to verify your language works. And so make it runnable from either Windows, Linux, Mac, or via a website.

  If it needs another program to run, such as CPython, the JVM, or a browser, that is fine. But it must be runnable on one of the above systems, or via a website.

  Since to do this we need to be able to get either a binary, or your code, entries need to produce a GitHub, or any other code sharing service, repository for their language. This allows entries to write Code Review questions on what they want reviewed, rather than a new question of their entire code on each change.
  This repository must be provided in the entry meta question on your entry.

Scoring

Each bullet point is worth one point. 'Functions' may be prefix, infix or postfix operators, normal functions, or any other method that's usable in your language.

For each bullet point that adds an additional function or feature write a test case/suite with at least one unit test for each additional function or feature.

• Implement all standard operators/functions.

  • addition (+)
  • subtraction (-)
  • multiplication (*)
  • division (/)
  • less than (<)
  • less than or equal (<=)
  • greater than (>)
  • greater than or equal (>=)
  • equal (==)
  • not equal (!=)
  • binary or (|)
  • binary xor (^)
  • binary and (&)
  • binary invert (~)
  • binary left shift (<<)
  • binary right shift (>>)
  • boolean and (&&)
  • boolean or (||)
• Implement operator precedence. Perform, say, multiplication and division before addition and subtraction.
• Use lexical analysis to generate a token stream.
• Use syntactic analysis to generate an AST, or related structure.
• Have your language be directly interpreted.
• Have your language compile to an intermediate language.
• Have your language compile to an intermediate language and then be executed by a 'virtual machine'. Your intermediate language must be custom-made in order to gain this point.
• Have your language compile directly to assembly.
• Write a Code Review question in your language.

In addition to the above you may also get points for implementing programming paradigms, according to Scoring of paradigm support. A big thanks to CAD97 for making such a large list, anyone can add to.

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I can't think of too many ways to score this, so if you can think of any, drop it as a comment, :)

Answer 2

Reposting Simon's answer from April:

Chess!

Last year ended with a board-game spree. Let's continue this year with one.

I think you all know the game of Chess, which is exactly why I just linked to the Wikipedia page. Even though everyone knows it, you might not know all the details about it.

What I like about a Chess challenge is that it can be both a small and a large challenge, depending on what you want to do with it. Let's take a look at some possible challenges for Chess: (feel free to pick the ones you want)

1. Implement logic to determine where/how pieces can move/attack
2. Determine which squares are threatened by what pieces
3. Implement support for some Chess notation (there are a bunch to choose from)
4. Given a history of chess moves, check if all moves are valid and figure out how the board looks like now.
5. Interact with the Lichess API for example use this data and implement the above
6. Make a GUI
7. Make a Chess computer opponent
8. Make a Chess computer opponent that beats Stockfish level 8 (good luck with that)
9. Implement some Chess variant such as Atomic Chess
10. Probably a bunch of other stuff

Scoring:

Item 1 is required. If you don't have that, it doesn't count as a submission. Items 2, 3, 4, 5, and 6 are worth one point for each variant supported, with another point for each variant implemented (item 9). Item 7 is significantly more difficult, so it gets 2 points for the engine and one point for the scoring system for each variant supported. If you implement item 8, you win outright and get a 500 point bounty from me (SE's limit).

Item 10 is rather vague, so I will give you one point per item implemented, but it has to be a serious feature of at least the complexity of item 1--in other words, don't try to bolster your ratings; if the community feels a player is attempting to do this, it is their responsibility to jointly decide a more fair rating. Additionally, if a player feels one point is too low for a feature's complexity, they can petition the community to grant them a higher score.

Answer 3

Create an image from any given file.

The objective is to create an image from any file, per instance, text file, audio file, or any other file. This is more of a challenge where people should be creative.

Just imagine see text as an image, or even an assembly! We programmers would finally be able to see code as an image (for the first time in history?).

Scoring:

1. Your program works on any text file (UTF-8) (1 point)
2. Your program works on any file type (1 point)
3. Your program does not require external libraries (1 point)
4. You are able to generate jpeg files (1 point)
5. You are able to generate png files (1 point)
6. You are able to generate bmp files (1 point)
7. You are able to generate gif files (2 points)
8. The generated image is different if the file type is different (1 point)
9. Relative beauty of generated images (this is a subjective qualification, post your results on your question!)

Total possible score: 9 + beauty

Answer 4

Allocate resources efficiently on a work environment

The company Code42Review demands that their employees are able to handle work items as efficiently as possible.

Those work items are assigned according to the work item chooser that decides which work items get assigned to which employees. The work item chooser takes into account the skills needed by a certain work item and tries to match them as close as possible to the skills of an employee. While some skills are mandatory others are "nice to have". The work item chooser may delay assignment due to not having any employee available with a required skill.

A work item only exists if a work candidate has acquired all resources sucessfully. Acquiring a resource is a process that may require time, in this particular work envoirnment, up to 20 seconds. The process of acquiring a resource is not guarteed to succeed because such resources might not be available. (the successful rate of resource acquisition is tipically under 50%)

In this work enviorment an employee may take up to several minutes to complete a work item. Usually something between 2 and 20 minutes. An employee that is handling a work item is considered to be busy and may not have another work item assigned to him.

A work item should be assigned to an employee within the shortest amount of time possible, if it's not assigned to an employee within a reasonable time, the resources may no longer be available. In this scenario the work item will be replaced by another.

Scoring

Your job is to create a program that does the following

1. Employees should spend the least amount of time possible waiting for work items (up to 10 points, scored according to the average amount of waiting time, 10 being awarded to the smallest)
2. Work items are discarded as few times as possible (up to 10 points, scored according to the amount of discarded work items, 10 being awarded to the smallest)
3. Work items are assigned to an employee within the shortest amount of time possible (up to 10 points, scored according to the average amount of assignment time, 10 being awarded to the smallest)
4. Work items are assigned to employees according to their skillet while respecting all the above (7 points, optional)
5. Do your own work environment simulator, according to the rules I stated. (if there is anything that is missing please edit, or comment, assume normal distribution) (7 points, optional)

Total score - 44 points.