ビットボンバーマン ver.2, 鍋谷さんの模範解答を参考にビット演算で書き直しました。

2013-03-01-bit-bomberman-v2.lisp

;;;; Last modified: 2013-11-27 20:05:56 tkych


;;====================================================================
;; Bit Bomberman ver.2
;;====================================================================

;; - [第8回オフラインリアルタイムどう書くの問題](http://qiita.com/Nabetani/items/709d61dff282cff7a890)
;; - [ビットボンバーマン 〜 横へな 2013.3.1](http://nabetani.sakura.ne.jp/hena/ord8biboma/)
;; - [鍋谷さんの模範解答: 第8回オフラインリアルタイムどう書く。ruby による実装例。](http://qiita.com/Nabetani/items/0a9fbd1d33ccfd533dc6)


;;--------------------------------------------------------------------

(in-package :cl-user)
(defpackage :bit-bomberman (:use :cl))
(in-package :bit-bomberman)


;;--------------------------------------------------------------------
;; Main
;;--------------------------------------------------------------------

;; (setf *print-base* 2) ;for DEV
;; (parse-input "802b1200/01400c20")
;; => 10000000001010110001001000000000, 1010000000000110000100000
(defun parse-input (input)
  (let ((split-pos (position #\/ input)))
    (values (parse-integer input :end split-pos :radix 16)
            (parse-integer input :start (1+ split-pos) :radix 16))))

;; MEMO:  cl:ASH = ruby:<<
(defun main (input)
  (multiple-value-bind (walls bombs) (parse-input input)
    (let* ((field    #.(mask-field (byte 31 2) #xFFFFFFFF))
           (no-walls (logand field (lognot walls)))
           (blast    bombs))
      (loop :for (shift mask) :in '((-1 #b11111011111011111011111011111000) ; Right
                                    ( 1 #b01111101111101111101111101111100) ; Left
                                    (-6 #xFFFFFFFF)  ; Down
                                    ( 6 #xFFFFFFFF)) ; Up
            :for fire := bombs
            :do (loop :until (zerop fire)
                      :do (setf blast (logior blast (logand fire field))
                                fire  (logand (ash (logand fire mask) shift)
                                              no-walls))))
      (format nil "~(~8,'0X~)" blast))))


#|
for DEV

(defun main (input)
  (multiple-value-bind (walls bombs) (parse-input input)
    (let* ((field    #.(mask-field (byte 31 2) #xFFFFFFFF))
           (no-walls (logand field (lognot walls)))
           (blast    bombs))
      (format t "~&Bombs:    ~32,'0B" bombs)
      (format t "~&No-Walls: ~32,'0B" no-walls) (terpri) (terpri)
      (loop :for (shift mask) :in '((-1 #b11111011111011111011111011111000)
                                    ( 1 #b01111101111101111101111101111100)
                                    (-6 #xFFFFFFFF)
                                    ( 6 #xFFFFFFFF))
            :for fire := bombs
            :do (format t "~&Mask:     ~32,'0B" mask)
                (terpri) (princ (make-string 42 :initial-element #\-))
                (loop 
                  :until (zerop fire)
                  :do (setf blast (logior blast (logand fire field))
                            fire (logand (ash (logand fire mask) shift)
                                         no-walls))
                      (format t "~&Blast:    ~32,'0B" blast)
                      (format t "~&Fire:     ~32,'0B" fire)
                      (terpri) (terpri)))
      (format t "~&Blast:    ~32,'0B" blast)
      (format nil "~(~8,'0X~)" blast))))


(main "802b1200/01400c20") => "53c40cfc"

Bombs:    00000001010000000000110000100000
No-Walls: 01111111110101001110110111111100

Mask:     11111011111011111011111011111000
------------------------------------------
Blast:    00000001010000000000110000100000
Fire:     00000000100000000000010000010000

Blast:    00000001110000000000110000110000
Fire:     00000000010000000000000000001000

Blast:    00000001110000000000110000111000
Fire:     00000000000000000000000000000100

Blast:    00000001110000000000110000111100
Fire:     00000000000000000000000000000000

Mask:     01111101111101111101111101111100
------------------------------------------
Blast:    00000001110000000000110000111100
Fire:     00000010100000000000100001000000

Blast:    00000011110000000000110001111100
Fire:     00000001000000000000000010000000

Blast:    00000011110000000000110011111100
Fire:     00000010000000000000000000000000

Blast:    00000011110000000000110011111100
Fire:     00000000000000000000000000000000

Mask:     11111111111111111111111111111111
------------------------------------------
Blast:    00000011110000000000110011111100
Fire:     00000000000001000000000000110000

Blast:    00000011110001000000110011111100
Fire:     00000000000000000000000000000000

Mask:     11111111111111111111111111111111
------------------------------------------
Blast:    00000011110001000000110011111100
Fire:     01010000000000000000100000000000

Blast:    01010011110001000000110011111100
Fire:     00000000000000000000000000000000

Blast:    01010011110001000000110011111100
|#


;;--------------------------------------------------------------------
;; Tests
;;--------------------------------------------------------------------

(defun =>? (got want)
  (assert (string= got want)))

(progn
  (=>? (main "802b1200/01400c20") "53c40cfc")
  (=>? (main "28301068/84080504") "d64fef94")
  (=>? (main "100a4010/80010004") "e241850c")
  (=>? (main "81020400/000000fc") "0e3cfbfc")
  (=>? (main "80225020/7e082080") "7fdd24d0")
  (=>? (main "01201200/40102008") "fe1861fc")
  (=>? (main "00201000/01000200") "43c48f08")
  (=>? (main "00891220/81020408") "ff060c1c")
  (=>? (main "410033c0/0c300000") "3cf0c000")
  (=>? (main "00000000/01400a00") "7bf7bf78")
  (=>? (main "00000000/20000a00") "fca2bf28")
  (=>? (main "00000000/00000000") "00000000")
  (=>? (main "00cafe00/00000000") "00000000")
  (=>? (main "aaabaaaa/50000000") "51441040")
  (=>? (main "a95a95a8/56a56a54") "56a56a54")
  (=>? (main "104fc820/80201010") "ea30345c")
  (=>? (main "4a940214/05000008") "05000008")
  (=>? (main "00908000/05000200") "ff043f48")
  (=>? (main "00c48c00/fe1861fc") "ff3873fc")
  (=>? (main "00000004/81020400") "fffffff0")
  (=>? (main "111028b0/40021100") "e08fd744")
  (=>? (main "6808490c/01959000") "17f7b650")
  (=>? (main "30821004/81014040") "c75de5f8")
  (=>? (main "0004c810/10003100") "fe4937c4")
  (=>? (main "12022020/88200000") "edf08208")
  (=>? (main "2aa92098/01160000") "45165964")
  (=>? (main "00242940/10010004") "fc43c43c")
  (=>? (main "483c2120/11004c00") "33c3de10")
  (=>? (main "10140140/44004a04") "eda3fe3c")
  (=>? (main "0c901d38/72602200") "f36da280")
  )


;;====================================================================