rectangular intersection

rectangle_intersect_exercise.rb

# write an algorithm to find the intersection of two users' love rectangles.

def intersection(rectangle1, rectangle2)
  rect_hash1 = calc_space(rectangle1)
  rect_hash2 = calc_space(rectangle2)
  intersect_hash = overlap(rect_hash1, rect_hash2)
  convert_to_rectangle(intersect_hash)
end

def calc_space(rectangle)
  rect_hash = {}
  rect_length_arr = [rectangle['left_x']] * rectangle['width']
  rect_length_arr.each_with_index do |_, i|
    rect_length_arr[i] += i
  end

  rectangle['height'].times do |i|
    rect_hash[rectangle['bottom_y'] + i] = rect_length_arr
  end

  rect_hash
end

def overlap(rect_hash1, rect_hash2)
  new_rect_hash = {}
  (rect_hash1.keys & rect_hash2.keys).each do |key|
    new_rect_hash[key] = rect_hash1[key] & rect_hash2[key]
  end
  new_rect_hash
end

def convert_to_rectangle(intersect_hash)
  rectangle_intersect = {}
  width_indeces  = intersect_hash.values
  height_indeces = intersect_hash.keys

  if width_indeces.empty? || height_indeces.empty?
    return "No intersection."
  end

  rectangle_intersect['left_x'] = width_indeces[0].min
  rectangle_intersect['bottom_y'] = height_indeces.min
  rectangle_intersect['width']  = width_indeces[0].count
  rectangle_intersect['height']   = height_indeces.count

  rectangle_intersect
end