Add move advantage bot

src/crosscram/samples/move_advantage.clj

@@ -0,0 +1,26 @@
+(ns crosscram.samples.move-advantage
+  "Maximizes the difference between the number of moves we'll have left and the
+  number of moves our opponent will have left."
+  (:require [crosscram.game :as cc]))
+
+(defn evaluate
+  [{:keys [board player-id] :as game}]
+  (let [our-moves (count (cc/available-moves board))
+        their-moves (-> board
+                      (cc/rotate-board 1)
+                      cc/available-moves
+                      count)]
+    (- our-moves their-moves)))
+
+(defn make-move
+  [game]
+  (let [board (:board game)
+        possible-states (map (partial cc/move game)
+                             (cc/available-moves board))]
+    (->> (for [gs possible-states]
+           ((juxt (comp last :history) evaluate) gs))
+      (reduce (fn [[_ best-val :as best] [_ val :as candidate]]
+                (if (> val best-val)
+                  candidate
+                  best)))
+      first)))