nim codewar

nim.clj

(ns nim)
 
(defn nim-sum [state]
  (apply bit-xor state))
  
(defn next-move [[i k] state]
  (cond 
    (<= (inc k) (nth state i)) [i (inc k)]
    (and (< (inc i) (count state)) (not= (nth state (inc i)) 0)) [(inc i) 1]
    (>= (inc i) (dec (count state))) nil
    :else (next-move [(+ 2 i) 0] state)))
  
(defn choose-move
  "Picks a move to play given a game-state ISeq"
  [game-state]
  (loop [[i k] (next-move [0 0] game-state)] 
    (if (or (= (nim-sum (assoc game-state i (- (nth game-state i) k))) 0) 
    				(= (next-move [i k] game-state) 
               nil))
      [i k]
      (recur (next-move [i k] game-state)))))