scoring-project.lsp

;;;;;;;;;;;;;;
;; GREED !! ;;
;;;;;;;;;;;;;;


;; Modified from Ruby Koans: about_scoring_project.rb

; *Greed* is a dice game where you roll up to five dice to accumulate
; points.  The following "score" function will be used to calculate the
; score of a single roll of the dice.
;
; A greed roll is scored as follows:
;
; * A set of three ones is 1000 points
;
; * A set of three numbers (other than ones) is worth 100 times the
;   number. (e.g. three fives is 500 points).
;
; * A one (that is not part of a set of three) is worth 100 points.
;
; * A five (that is not part of a set of three) is worth 50 points.
;
; * Everything else is worth 0 points.
;
;
; Examples:
;
; (score '(1 1 1 5 1)) => 1150 points
; (score '(2 3 4 6 2)) => 0 points
; (score '(3 4 5 3 3)) => 350 points
; (score '(1 5 1 2 4)) => 250 points
;
; More scoring examples are given in the tests below:
;
; Your goal is to write the score method.

(defun calc (kv)
  (multiple-value-bind (di re) (truncate (cdr kv) 3)
    (cond
      ((= 1 (car kv)) (+ (* 1000 di) (* 100 re)))
      ((= 5 (car kv)) (+ (* 500 di) (* 50 re)))
      ((= 3 (cdr kv)) (* (car kv) 100))
      (t 0))))

(defun score (dice)
  (let ((sum 0)
	(hash 
	 (loop for i from 1 to 6 collect (cons i (count i dice)))))
    (dolist (kv hash)
      (setf sum (+ sum (calc kv))))
    sum))