(load "a4code")
(load "connect4")

(define (c4-eval board current-player max-player)
  (let ((winner (c4-end? board)))
    (cond ((equal? winner max-player) 1000)
	  ((equal? winner (other-player max-player)) -1000)
	  ((equal? winner 'draw) 0)
	  (else
	   (let ((max-c-threes (cadr (open-columns board max-player)))
		 (min-c-threes (cadr (open-columns board
						   (other-player max-player))))
		 (max-r-threes (apply + (map cadr
					     (open-rows board max-player))))
		 (min-r-threes 
		  (apply + (map cadr 
				(open-rows board (other-player max-player))))))
	     (+ max-c-threes 
		max-r-threes
		(- min-c-threes)
		(- min-r-threes)))))))