2023-02-01 clojure meetup

probability.clj

;; 2 blue balls, 6 yellow balls
;; opt a - take 3, win if there are not 2 blue
;; opt b - take 1, win if it isn't blue
;; which option better?

;;(def bag {:blueballs  #{'x 'y} :yellow-balls #{'a 'b 'c 'd 'e 'f}})
;;(def bag [1 1 0 0 0 0 0 0])

(def prototype-bag 
  [:yellow :yellow :yellow :yellow :yellow :yellow :blue :blue])

#_(#{:blue} :x)

(defn win-option-a? [bag]
  (let [pics (take 3 bag)
        num-blue (count (filter #{:blue} pics))]
     (not= num-blue 2)))

#_(win-option-a? [:blue :blue :yellow])
#_(win-option-a? [:blue :yellow :yellow])
#_(win-option-a? [:yellow :yellow :yellow])

;; opt b - take 1, win if it isn't blue
(defn win-option-b? [bag]
  (let [ball (first bag)]
    (not= ball :blue)))

#_(win-option-b? [:blue])
#_(win-option-b? [:yellow])

#_(->> (repeat 100000 prototype-bag)
       (map shuffle)
       (reduce (fn [[target-count total-count] item]
                 [(if (win-option-a? item)
                    (inc target-count)
                    target-count)
                  (inc total-count)])   
               [0 0.0])
       (apply /))

#_(->> (repeat 100000 prototype-bag)
       (map shuffle)
       (map win-option-a?)
       (filter true?)
       count
       (#(/ % 100000.0)))
       
#_(->> (repeat 100000 prototype-bag)
       (map shuffle)
       (map win-option-b?)
       (filter true?)
       count
       (#(/ % 100000.0)))