Implement example yacht solution

exercises/practice/yacht/.meta/config.json

@@ -1,5 +1,7 @@
 {
-  "authors": [],
+  "authors": [
+    "mr-sigma"
+  ],
   "files": {
     "solution": [
       "yacht.rb"
@@ -8,7 +10,7 @@
       "yacht_test.rb"
     ],
     "example": [
-      ".meta/solutions/yacht.rb"
+      ".meta/example.rb"
     ]
   },
   "blurb": "Score a single throw of dice in the game Yacht.",

exercises/practice/yacht/.meta/example.rb

@@ -0,0 +1,76 @@
+class Yacht
+  attr_reader :dice, :category
+
+  def initialize(dice, category)
+    @dice = dice.sort
+    @category = category
+  end
+
+  def score
+    case category
+    when 'ones' then count_occurances(1)
+    when 'twos' then count_occurances(2) * 2
+    when 'threes' then count_occurances(3) * 3
+    when 'fours' then count_occurances(4) * 4
+    when 'fives' then count_occurances(5) * 5
+    when 'sixes' then count_occurances(6) * 6
+    when 'yacht' then yacht
+    when 'full house' then full_house
+    when 'four of a kind' then four_of_a_kind
+    when 'little straight' then little_straight
+    when 'big straight' then big_straight
+    else choice
+    end
+  end
+
+  private
+  def count_occurances(number)
+    dice.tally({})[number] || 0
+  end
+
+  def yacht
+    yacht? ? 50 : 0
+  end
+
+  def full_house
+    full_house? ? dice.sum : 0
+  end
+
+  def four_of_a_kind
+    return 0 unless four_of_a_kind?
+
+    dice.tally({}).select { |_, v| v >= 4 }.keys.first * 4
+  end
+
+  def little_straight
+    little_straight? ? 30 : 0
+  end
+
+  def big_straight
+    big_straight? ? 30 : 0
+  end
+
+  def choice
+    dice.sum
+  end
+
+  def yacht?
+    dice.uniq.length == 1
+  end
+
+  def full_house?
+    dice.uniq.length == 2 && !four_of_a_kind?
+  end
+
+  def four_of_a_kind?
+    dice.uniq.length <= 2 && (dice.slice(0..4).uniq.length == 1 || dice.slice(1..-1).uniq.length == 1)
+  end
+
+  def little_straight?
+    dice.eql?([1, 2, 3, 4, 5])
+  end
+
+  def big_straight?
+    dice.eql?([2, 3, 4, 5, 6])
+  end
+end