サイコロを転がす, http://qiita.com/Nabetani/items/f3cca410428f90333e28

2013-07-06-roll-dice.lisp

;;;; Last modified: 2014-01-06 20:05:00 tkych


;;====================================================================
;; サイコロを転がす
;;====================================================================
;; - [サイコロを転がす 〜 横へな 2013.7.6](http://nabetani.sakura.ne.jp/hena/ord12rotdice/)
;; - [第12回オフラインリアルタイムどう書くの問題](http://qiita.com/Nabetani/items/f3cca410428f90333e28)


;;--------------------------------------------------------------------
;; Package
;;--------------------------------------------------------------------

(in-package :cl-user)
(defpackage :rolling-dice (:use :cl))
(in-package :rolling-dice)


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

(defun back (side) (- 7 side))

(defun main (input)
  (with-output-to-string (s)
    (princ 1 s)  ; はじまりはいつも1
    (loop :for dir :across input
          :with top := 1 :and north := 2 :and east := 4
          :do (ecase dir
                (#\N (psetf top   (back north)
                            north top))
                (#\E (psetf top   (back east)
                            east  top))
                (#\S (psetf top   north
                            north (back top)))
                (#\W (psetf top   east
                            east  (back top))))
              (princ top s))))


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

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

(progn
  (=>? (main "NNESWWS") "15635624")
  (=>? (main "EEEE") "13641")
  (=>? (main "WWWW") "14631")
  (=>? (main "SSSS") "12651")
  (=>? (main "NNNN") "15621")
  (=>? (main "EENN") "13651")
  (=>? (main "WWNN") "14651")
  (=>? (main "SSNN") "12621")
  (=>? (main "NENNN") "153641")
  (=>? (main "NWNNN") "154631")
  (=>? (main "SWWWSNEEEN") "12453635421")
  (=>? (main "SENWSWSNSWE") "123123656545")
  (=>? (main "SSSWNNNE") "126546315")
  (=>? (main "SWNWSSSWWE") "12415423646")
  (=>? (main "ENNWWS") "1354135")
  (=>? (main "ESWNNW") "1321365")
  (=>? (main "NWSSE") "154135")
  (=>? (main "SWNWEWSEEN") "12415154135")
  (=>? (main "EWNWEEEEWN") "13154532426")
  (=>? (main "WNEWEWWWSNW") "145151562421")
  (=>? (main "NNEE") "15631")
  (=>? (main "EEEEWNWSW") "1364145642")
  (=>? (main "SENNWWES") "123142321")
  (=>? (main "SWWWSNSNESWW") "1245363635631")
  (=>? (main "WESSENSE") "141263231")
  (=>? (main "SWNSSESESSS") "124146231562")
  (=>? (main "ENS") "1353")
  (=>? (main "WNN") "1453")
  (=>? (main "SSEENEEEN") "1263124536")
  (=>? (main "NWSNNNW") "15414632")
  (=>? (main "ESSSSSWW") "132453215")
  (=>? (main "ESE") "1326")
  (=>? (main "SNWNWWNSSSS") "121456232453")
  (=>? (main "SWEESEN") "12423653")
  (=>? (main "NEEWNSSWWW") "15323631562")
  (=>? (main "WSEW") "14212")
  (=>? (main "SWSNNNSNWE") "12464131353")
  (=>? (main "ENWEWSEEW") "1351513545")
  (=>? (main "WSEWN") "142124")
  (=>? (main "EWNEESEWE") "1315321414")
  (=>? (main "NESEEN") "1531263")
  (=>? (main "WSW") "1426")
  (=>? (main "ENEWE") "135656")
  )

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