spiral.rb

require 'benchmark'
require 'bigdecimal/math'

number = 0
array = Array.new(15){ Array.new(15, number += 1) }

def spiral(array)
  spiral = []
  spiral << array.delete_at(0)
  return spiral.flatten if array.empty?
  spiral += spiral(array.transpose.reverse)
end

def spiral_refactor(array)
  spiral = []
  spiral << array.delete_at(0)
  spiral += spiral(array.transpose.reverse) unless array.empty?
  spiral.flatten
end

def spiral_splat(array) # not mine: https://gist.github.com/jfarmer/d0f37717f6e7f6cebf72
  return [] if array.empty?
 
  first, *rest = *array
 
  return first + spiral(rest.transpose.reverse)
end


p spiral(array)
puts Benchmark.measure { 1000.times { spiral(array) } }

#  0.000000   0.000000   0.000000 (  0.003572)
#  0.000000   0.000000   0.000000 (  0.003431)
#  0.000000   0.000000   0.000000 (  0.003619)

puts Benchmark.measure { 1000.times { spiral_refactor(array) } }

#  0.000000   0.000000   0.000000 (  0.001334)
#  0.000000   0.000000   0.000000 (  0.001342)
#  0.000000   0.000000   0.000000 (  0.001271)
puts Benchmark.measure { 1000.times { spiral_splat(array) } }
 
#  0.000000   0.000000   0.000000 (  0.000334)
#  0.000000   0.000000   0.000000 (  0.000328)
#  0.000000   0.000000   0.000000 (  0.000342)

#This is the resulting array of integers split by line.
#[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
#2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 
#15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 
#14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 
#2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
#3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 
#14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 
#13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 
#3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 
#4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 
#13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 
#12, 11, 10, 9, 8, 7, 6, 5, 4, 
#4, 4, 4, 4, 4, 4, 4, 4, 4,
#5, 6, 7, 8, 9, 10, 11, 12, 
#12, 12, 12, 12, 12, 12, 12, 12, 
#11, 10, 9, 8, 7, 6, 5, 
#5, 5, 5, 5, 5, 5, 5, 
#6, 7, 8, 9, 10, 11, 
#11, 11, 11, 11, 11, 11, 
#10, 9, 8, 7, 6, 
#6, 6, 6, 6, 6, 
#7, 8, 9, 10, 
#10, 10, 10, 10, 
#9, 8, 7, 
#7, 7, 7, 
#8, 9, 
#9, 9, 
#8, 8]