Spiral Fun

gistfile1.rb

def spiral(root)
  return [1] if root == 1
  return [[4,3],[1,2]] if root == 2

  grid = spiral(root - 1)
  num = (root - 1) ** 2 + 1

  if root % 2 == 0
    grid.reverse_each do |row|
      row << num
      num += 1
    end

    new_row = []
    root.times do
      new_row.unshift num
      num += 1
    end
    grid.unshift new_row
  else
    grid.each do |row|
      row.unshift num
      num += 1
    end

    new_row = []
    root.times do
      new_row << num
      num += 1
    end
    grid << new_row
  end

  grid
end

input = ARGV.shift
value = input.to_i
root = Math.sqrt(value).to_i
if input && (root ** 2 == value)
  grid = spiral(root)
  char_length = value.to_s.length

  grid.each do |row|
    row.each {|i| print "%#{char_length}d " % i }
    puts
  end
else
  puts "Please provide an integer value for a perfect square"
end