这里有一个程式源
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;;; -*-Lisp-*-
(in-package :user)
(use-package :kgk)
;;; ----------------------------------------------------------------------
(defun make-shoe (decks)
(let* ((size (* decks 52))
(v (make-array size))
(index size)
(cards
(make-periodic
'(1
; ace
2 3 4 5 6 7 8 9 0
; 2 through 10
0 0 0)))
; :j, :q, :k
)
(dotimes (i size)
(setf (aref v i) (pop cards)))
#'(lambda (&optional shuffle)
(when (or shuffle (= index size))
(setf index 0)
(shuffle! v))
(unless shuffle
(prog1 (aref v index)
(incf index))))))
(defun sum (a b)
"Determine the value of a Baccarat hand (either two or three cards)"
(mod (+ a b) 10))
(defun trial (hit)
(let* ((p (sum (funcall hit) (funcall hit)))
; player
(d (sum (funcall hit) (funcall hit)))
; dealer (bank)
)
;; pick more cards unless one or both sides has a "natural"
(unless (or (>= p 8)
; a "natural" for the player
(>= d 8)
; a "natural" for the dealer
)
;; consider drawing a third card for the player
(let ((p3 nil))
(when (<= p 5)
(setf p3 (funcall hit))
(setf p (sum p p3)))
;; consider drawing a third card for the dealer
(when (if (null p3)
(<= d 5)
(or
(<= d 2)
(and (= d 3)
(/= p3 8))
(and (= d 4)
(<= 2 p3 7))
(and (= d 5)
(<= 4 p3 7))
(and (= d 6)
(<= 6 p3 7))))
(setf d (sum (funcall hit) d)))))
;; pick the winner
(cond ((= p d) :tie)
((< p d) :bank)
(t :player))))
(defun play-hands (&optional (n 10000000))
"Play a million hands of Baccarat and count the winners."
(let ((player-wins 0)
(bank-wins 0)
(tie 0)
(shoe (make-shoe 8)))
(dotimes (i n)
(ecase (trial shoe)
(:tie (incf tie))
(:bank (incf bank-wins))
(:player (incf player-wins))))
;; report the results
(values (float (/ bank-wins n))
(float (/ player-wins n))
(float (/ tie n)))))
;;; ----------------------------------------------------------------------
(defun estimate-losses (&key
(commission 0.05)
;; these values came by running play-hands for 50M hands
(tie-return 9)
(p-bank 0.4586346)
(p-player 0.4461371)
(p-tie 0.0952283))
"Figure out the losses in Baccarat"
(labels ((note (situation &key (player-return 0) (bank-return 0) (tie-return 0))
(format t "Select ~A and lose ~A%.~&"
situation
(* 100 (+ (* p-bank bank-return)
(* p-player player-return)
(* p-tie tie-return))))))
(note "player" :player-return 1 :bank-return -1 :tie-return 0)
(note "bank" :player-return -1 :bank-return (- 1 commission) :tie-return 0)
(note "tie" :player-return -1 :bank-return -1 :tie-return tie-return)))
;;; ----------------------------------------------------------------------
