flengyel-4clojure-solution94.clj

;; flengyel's solution to Game of Life
;; https://4clojure.com/problem/94

(fn [board]
  (letfn [ (remap [board]
    (->> (for [v board] 
           (->> (map (fn [c] (if (= (str c) " ") 0 1)) v)
                (apply vector)))
          (apply vector)))
(unmap [matrix]
    (->> (for [v matrix] 
           (->> (map (fn [b] (if (zero? b) " " "#")) v)
                (apply str)))
          (apply vector)))
(cneigh [matrix x y]
   (let [n (count matrix)
         left (mod (dec x) n)
         right (mod (inc x) n)
         up   (mod (dec y) n)
         down (mod (inc y) n)]
     (->>
         (for [[a b] [[left up] [x up]  [right up]
                     [left y]           [right y]
                     [left down][x down][right down]]]
               ((matrix a)b))
               (reduce +)))) 
(nextgen [matrix]
  (let [n (count matrix)]
    (->>
      (for [x (range n)] 
  	(->>
           (for [y (range n)]
              (let [neighbors (cneigh matrix x y)]
                 (if (zero? ((matrix x)y))
				    (if (= neighbors 3) 1 0)
                    (cond
                         (or (= neighbors 2) (= neighbors 3)) 1
                         :else 0))))
 			(apply vector)))
	  (apply vector))))]
   (->> board (remap) (nextgen) (unmap))))