New York Times SET puzzle solver

set_solver.rb

# Brute force NYT set Solver.
# from https://www.nytimes.com/puzzles/set - Accessed Jan 6

require 'set'

class Item
  include Comparable

  attr_accessor :color, :shape, :pattern, :item_count

  def initialize(color:, shape:, pattern:, item_count:)
    self.color = color
    self.shape = shape
    self.pattern = pattern
    self.item_count = item_count
  end

  def inspect
    "#{color} #{shape} #{pattern} #{item_count}"
  end

end

class ItemSet

  attr_accessor :items

  def initialize(params)
    @name = params[:name]
    @items = []
    @solutions = []
  end

  def add_item(item_color, item_shape, item_pattern, item_count)
    items << Item.new(color: item_color, shape: item_shape, pattern: item_pattern, item_count: item_count)
  end

  def solve!
    # find unique sets.
    # look_for_same_color

    puts "\nSolving #{@name}"
    permutations = items.permutation(3).to_a
    puts "#{permutations.count} permutations"

    permutations.each do |perm|
      @solutions << Set[*perm] if valid_set?(Set[*perm])
    end

    @solutions.uniq.each do |s| 
      puts s.inspect
    end
  end

  private

  # This is a card-matching game. Cards have 4 features, each with 3 variations:
  # A SET is 3 cards for which each feature is either common across all 3 cards or is different on each card.
  def valid_set?(items = Set[])
    return false if items.count != 3

    _color_count = items.map{|i| i.color}.uniq.count
    _shape_count = items.map{|i| i.shape}.uniq.count
    _pattern_count = items.map{|i| i.pattern}.uniq.count
    _count_count = items.map{|i| i.item_count}.uniq.count

    _color = (_color_count == 1 || _color_count == 3)
    _shape = (_shape_count == 1 || _shape_count == 3)
    _pattern = (_pattern_count == 1 || _pattern_count == 3)
    _count = (_count_count == 1 || _count_count == 3)

    return [_color,_shape,_pattern,_count].count(true) == 4
  end

end

item_set = ItemSet.new(name: "Basic 1")

item_set.add_item(:green, :diamond, :striped, 1)
item_set.add_item(:green, :diamond, :solid, 1)
item_set.add_item(:purple, :diamond, :striped, 2)

item_set.add_item(:green, :diamond, :striped, 3)
item_set.add_item(:green, :diamond, :bordered, 2)
item_set.add_item(:purple, :diamond, :bordered, 3)

item_set.add_item(:purple, :diamond, :solid, 1)
item_set.add_item(:red, :diamond, :striped, 2)
item_set.add_item(:red, :diamond, :striped, 1)

item_set.solve!

# Advanced 1
item_set = ItemSet.new(name: "Advanced 1")

item_set.add_item(:red, :squiggly, :bordered, 2)
item_set.add_item(:red, :squiggly, :striped, 2)
item_set.add_item(:red, :squiggly, :striped, 1)

item_set.add_item(:purple, :oval, :bordered, 2)
item_set.add_item(:purple, :diamond, :bordered, 2)
item_set.add_item(:green, :oval, :solid, 3)

item_set.add_item(:red, :squiggly, :solid, 2)
item_set.add_item(:purple, :squiggly, :solid, 3)
item_set.add_item(:purple, :diamond, :striped, 1)

item_set.add_item(:purple, :oval, :striped, 2)
item_set.add_item(:green, :diamond, :striped, 2)
item_set.add_item(:red, :oval, :solid, 2)

item_set.solve!

# Advanced 2
item_set = ItemSet.new(name: "Advanced 2")

item_set.add_item(:purple, :squiggly, :solid, 1)
item_set.add_item(:purple, :diamond, :striped, 3)
item_set.add_item(:green, :oval, :solid, 2)

item_set.add_item(:purple, :diamond, :solid, 2)
item_set.add_item(:red, :oval, :bordered, 3)
item_set.add_item(:purple, :oval, :striped, 1)

item_set.add_item(:green, :diamond, :bordered, 3)
item_set.add_item(:green, :squiggly, :striped, 1)
item_set.add_item(:red, :squiggly, :solid, 3)

item_set.add_item(:green, :oval, :bordered, 3)
item_set.add_item(:red, :diamond, :striped, 1)
item_set.add_item(:red, :squiggly, :bordered, 2)

item_set.solve!

Output is

Solving Basic 1
504 permutations
#<Set: {green diamond solid 1, green diamond striped 3, green diamond bordered 2}>
#<Set: {green diamond solid 1, purple diamond bordered 3, red diamond striped 2}>
#<Set: {purple diamond striped 2, green diamond striped 3, red diamond striped 1}>
#<Set: {purple diamond striped 2, purple diamond bordered 3, purple diamond solid 1}>

Solving Advanced 1
1320 permutations
#<Set: {red squiggly bordered 2, red squiggly striped 2, red squiggly solid 2}>
#<Set: {red squiggly bordered 2, green oval solid 3, purple diamond striped 1}>
#<Set: {red squiggly striped 2, purple oval striped 2, green diamond striped 2}>
#<Set: {red squiggly striped 1, purple diamond bordered 2, green oval solid 3}>
#<Set: {purple oval bordered 2, red squiggly solid 2, green diamond striped 2}>
#<Set: {purple oval bordered 2, purple squiggly solid 3, purple diamond striped 1}>

Solving Advanced 2
1320 permutations
#<Set: {purple diamond striped 3, red squiggly solid 3, green oval bordered 3}>
#<Set: {green oval solid 2, red oval bordered 3, purple oval striped 1}>
#<Set: {green oval solid 2, green diamond bordered 3, green squiggly striped 1}>
#<Set: {purple diamond solid 2, red oval bordered 3, green squiggly striped 1}>
#<Set: {purple diamond solid 2, green diamond bordered 3, red diamond striped 1}>
#<Set: {purple oval striped 1, green squiggly striped 1, red diamond striped 1}>