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Problem for Programming challenge October
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Japanese Mosaic Logic Puzzle

For rules and examples of the Japanese Mosaic problem you should take a look at the Cucumber acceptance tests.


If you’re not sure what Cucumber is take a quick peek here

We will use these Examples to drive the development of your solution.

1 Prerequisites

The acceptance tests for these examples require Ruby and Cucumber.

So we need the following installed:

  1. Git (and a github account:
  2. Ruby (or JRuby whatever floats your boat)
  3. Rubygems (

2 Setup

  1. Fork my repository on Github (
  2. git clone your repository
  3. gem install bundler
  4. cd japanese-mosaic-logic-puzzle && bundle install

We can now run that Cucumber specification:

cucumber features/mosaic.feature

You should be greeted with lots of fails. Right here the work starts, work your way down the scenarios getting each to pass in turn.

3 Coding

You have to ensure that executing “bin/mosaic” prints the solution on the command line.

The file “bin/mosaic” will be executed with a filename which will contain the input string.

4 First steps

bin/mosaic file:

#!/usr/bin/env ruby
filename = ARGV[0] # The first argument is the filename with the input table string do |f|
  string_input_table =
  input_array = string_input_table.split("\n").map{|row| row.split("|")[1..-1]}

puts “I should output the solution here.”

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