The purpose for this repo is to solve the Hell Triangle challenge using Ruby. I am currently studying Ruby and that's why the reason of the chosen language. As well that project introduce me to the awesome RSpec syntax :).

The challenge:

Given a triangle of numbers, find the maximum total from top to bottom
Example:
       6
      3 5
     9 7 1
    4 6 8 4
In this triangle the maximum total is: 6 + 5 + 7 + 8 = 26

An element can only be summed with one of the two nearest elements in the next row.
For example: The element 3 in the 2nd row can only be summed with 9 and 7, but not with
1

Your code will receive an (multidimensional) array as input.
The triangle from above would be:

    example = [[6],[3,5],[9,7,1],[4,6,8,4]]

First, we need to install Homebrew. Homebrew allows us to install and compile software packages easily from source.

Homebrew comes with a very simple install script. When it asks you to install XCode CommandLine Tools, say yes.

Open Terminal and run the following command:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Before we begin, make sure you have ruby version >=2.2.2 and rails version 5.

$ ruby -v # ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin16]

Ruby comes by default in Mac OS Sierra and El Capitan. If not, it will be easy after we already installed Homebrew.

$ brew install ruby

This should install the lastest version of Ruby

Sometimes you need to update it using some third party Ruby Manager. Check out the references of these third party Managers for Ruby under Installers topic.

Bundler provides a consistent environment for Ruby projects by tracking and installing the exact gems and versions that are needed.

Bundler is an exit from dependency hell, and ensures that the gems you need are present in development, staging, and production. Starting work on a project is as simple as bundle install.

After installing ruby tap gem install bundler

The project is set to resolve the given challenge example. If you want to, open the main.rb file to setup the challenge with other inputs examples changing the example variable to the one of your preference.

• Clone the repo
  • $ git clone https://github.com/lsfernandes92/hell-triangle.git
• Enter in the folder
  • cd hell-triangle/
• Tap the command and see the result in the terminal
  • ruby lib/main.rb

The tests are build with RSpec and they are found in rails-api/spec folder.

Follow the instructions to run:

• Enter in the folder
  • cd rails-api/
• Install RSpec gem
  • bundle install
• Let's execute the specs by running:
  • rspec --format doc

You should get something like that if all good.

HellTriangle
  .verify_triangle
    verify a given triangle if its a valid one
      return false if triangle equal nil
Favor inserir um triangulo válido para o exercício
      return false if no number added
Favor inserir um triangulo válido para o exercício
      return false if just one number added
      the real triangle

Triangle
  .<<
    add some elements
      return empty if no number added
      return empty if triangle is nil
      possible to put element on it
  .total_lines
    get sizes of triangle
      verify size after added nil
      validate size if no number added
      validate size if number added
  .is_triangle?
    garantee that the input is an triangle
      not triangle if nil added
      not triangle if no number added
      not triangle if just one element added
      the real triangle
  .empty?
    test possibilities of triangle been empty
      should be empty if nil added
      should be empty if no number added
      shouldn't be empty if just one element added

Finished in 0.00727 seconds (files took 0.12734 seconds to load)
17 examples, 0 failures

This project is licensed under the MIT License - see the LICENSE.md file for details