Arigeom beats kata

Arigeom/.rspec

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+--color
+--format progress

Arigeom/Guardfile

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+# A sample Guardfile
+# More info at https://github.com/guard/guard#readme
+
+guard 'rspec', :version => 2 do
+  watch(%r{^spec/.+_spec\.rb$})
+  watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }
+  watch('spec/spec_helper.rb')  { "spec" }
+
+  # Rails example
+  watch(%r{^app/(.+)\.rb$})                           { |m| "spec/#{m[1]}_spec.rb" }
+  watch(%r{^app/(.*)(\.erb|\.haml)$})                 { |m| "spec/#{m[1]}#{m[2]}_spec.rb" }
+  watch(%r{^app/controllers/(.+)_(controller)\.rb$})  { |m| ["spec/routing/#{m[1]}_routing_spec.rb", "spec/#{m[2]}s/#{m[1]}_#{m[2]}_spec.rb", "spec/acceptance/#{m[1]}_spec.rb"] }
+  watch(%r{^spec/support/(.+)\.rb$})                  { "spec" }
+  watch('config/routes.rb')                           { "spec/routing" }
+  watch('app/controllers/application_controller.rb')  { "spec/controllers" }
+  # Capybara request specs
+  watch(%r{^app/views/(.+)/.*\.(erb|haml)$})          { |m| "spec/requests/#{m[1]}_spec.rb" }
+end
+

Arigeom/lib/arigeom.rb

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+class Arigeom
+  def permutations(set)
+    options = []
+    (2..set.length).each do |size|
+      o = set.combination(size).to_a
+      options += o
+    end
+    options
+  end
+
+  def geometric_change(set)
+    differ(set) do |cur, last|
+      cur.to_f / last.to_f
+    end
+  end
+
+  def arithmetic_change(set)
+    differ(set) do |cur, last|
+      cur - last
+    end
+  end
+
+  def find_geometric(set)
+    options = permutations(set)
+    changes = options.map { |o| {set: o, change: geometric_change(o)} }
+    sets = changes.select {|o| o[:change].uniq.length == 1 }
+    sets = sets.map { |o| o[:set] }
+    sets.last
+  end
+
+  def find_arithmetic(set)
+    options = permutations(set)
+    changes = options.map { |o| {set: o, change: arithmetic_change(o)} }
+    sets = changes.select {|o| o[:change].uniq.length == 1 }
+    sets = sets.map { |o| o[:set] }
+    sets.last
+  end
+
+  private
+
+  def differ(set, &block)
+    options = set.dup
+    last = options.shift
+    options.map do |s|
+      change = yield(s, last)
+      last = s
+      change
+    end
+  end
+end

Arigeom/spec/arigeom_spec.rb

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+require 'spec_helper'
+
+describe Arigeom do
+  subject { described_class.new }
+  describe :permutations do
+    it "returns arrays of possibe sets for current length" do
+      result = subject.permutations [1,2,3,4]
+      result.to_a.should == [
+        [1,2],
+        [1,3],
+        [1,4],
+        [2,3],
+        [2,4],
+        [3,4],
+        [1,2,3],
+        [1,2,4],
+        [1,3,4],
+        [2,3,4],
+        [1,2,3,4]
+      ]
+    end
+  end
+
+  describe :geometric_change do
+    it "returns difference ratio between numbers" do
+      subject.geometric_change([2,4,8,16]).should == [2,2,2]
+      subject.geometric_change([2,4,12,66]).should == [2,3,5.5]
+    end
+  end
+
+  describe :arithmetic_change do
+    it "returns the differences between numbers" do
+      subject.arithmetic_change([2,4,6,8]).should == [2,2,2]
+      subject.arithmetic_change([2,6,12,20]).should == [4,6,8]
+    end
+  end
+
+  describe :find_geometric do
+    it "returns largest combination with equal geometric change" do
+      subject.find_geometric([2,4,5,8,11,16]).should == [2, 4, 8, 16]
+      subject.find_geometric([1,2,3,4,5]).should == [1,2,4]
+      subject.find_geometric([1,3,9,10,19,27,28,81]).should == [1,3,9,27,81]
+      subject.find_geometric([1,4,7,10,13,25]).should == [4,10,25]
+    end
+  end
+
+  describe :find_arithmetic do
+    it "returns largest combination with equal arithmetic change" do
+      subject.find_arithmetic([2,4,5,8,11,16]).should == [2,5,8,11]
+      subject.find_arithmetic([1,2,3,4,5]).should == [1,2,3,4,5]
+      subject.find_arithmetic([1,3,9,10,19,27,28,81]).should == [1,10,19,28]
+      subject.find_arithmetic([1,4,7,10,13,25]).should == [1,4,7,10,13]
+    end
+  end
+end
+

Arigeom/spec/spec_helper.rb

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+# This file was generated by the `rspec --init` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# Require this file using `require "spec_helper.rb"` to ensure that it is only
+# loaded once.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+
+require 'arigeom'
+
+RSpec.configure do |config|
+  config.treat_symbols_as_metadata_keys_with_true_values = true
+  config.run_all_when_everything_filtered = true
+  config.filter_run :focus
+end