array flatten example

#!/usr/bin/env ruby

# Write some code, that will flatten an array of arbitrarily nested arrays of
# integers into a flat array of integers. e.g. [[1,2,[3]],4] -> [1,2,3,4].

# Your solution should be a link to a gist on gist.github.com
# with your implementation.

# When writing this code, you can use any language you're comfortable with.
# The code must be well tested and documented if necessary,
# and in general please treat the quality of the code as if it was ready
# to ship to production.

# Try to avoid using language defined methods like Ruby's Array#flatten.*

require 'benchmark'
require 'pp'

# flattens any deep level array using recursing strategy
class Array
  def flat
    each_with_object([]) do |element, obj|
      if element.kind_of? Array
        # if element is array call self again with sub-array as an arguement
        element.flat.each { |sub_element| obj << sub_element }
      else
        obj << element
      end
    end
  end
end

sample1 = [1, 2, [(1..10_000).to_a]]
sample2 = [[1, 2], [(1..10_000).to_a]]
sample3 = [17, [22, [33, 123], 555, [8, 12, 8]]]
sample4 = [[[]]]
sample5 = [9, 8, 7, [], 6, [5], [4, 3]]
sample6 = [[1, 2, [3]], 4]

Benchmark.bm do |x|
  x.report { 100.times { sample1.flat } }
  x.report { 100.times { sample2.flat } }
  x.report { 100.times { sample3.flat } }
  x.report { 100.times { sample4.flat } }
  x.report { 100.times { sample5.flat } }
  x.report { 100.times { sample6.flat } }
end

# print small arrays just to show it's working properly
pp sample3.flat
pp sample4.flat
pp sample5.flat
pp sample6.flat