オフラインリアルタイムどう書く四回をrubyで解いてみた

tm.rb

require 'test/unit'

class TM
  def self.calc(ary)
    ary.sort!.map!(&:to_i)
    touch_info = ary.permutation(2).map { |a,b| check_touch(a, b) }
    touch_numbers = touch_info.each_slice(3).map {|i| i.compact.length }

    return 'T' if touch_numbers.max == 3
    return 'O' if touch_numbers.all? { |i| i == 2 }
    if touch_numbers.max == 2 && touch_numbers.count(2) == 2
      ils = case touch_info.each_slice(3).count {|i| touch_xy? i }
            when 0; 'I'
            when 1; 'L'
            when 2; 'S'
            end
      return ils
    end
    '-'
  end

  def self.touch_xy?(ary)
    ary.compact.count('X') > 0 && ary.compact.count('Y') > 0
  end

  def self.check_touch(a, b)
    return 'X' if a - 1 == b || a + 1 == b
    return 'Y' if a - 10 == b || a + 10 == b
    nil
  end
end

class TestTM < Test::Unit::TestCase
  def test_calc_ramdom
    assert_equal(TM.calc(%w(03 11 13 01)), '-')
  end

  def test_calc_dup
    assert_equal(TM.calc(%w(55 55 55 55)), '-')
  end

  def test_calc_L
    assert_equal(TM.calc(%w(07 17 06 05)), 'L')
  end

  def test_calc_T
    assert_equal(TM.calc(%w(89 99 79 88)), 'T')
  end

  def test_calc_O
    assert_equal(TM.calc(%w(68 57 58 67)), 'O')
  end

  def test_calc_S
    assert_equal(TM.calc(%w(43 54 53 42)), 'S')
  end

  def test_calc_I
    assert_equal(TM.calc(%w(24 22 25 23)), 'I')
  end
end