;; -*- coding: utf-8 -*-
(eval-when (:compile-toplevel :load-toplevel :execute)
  (sb-int:defconstant-eqx OPT
    #+swank '(optimize (speed 3) (safety 2))
    #-swank '(optimize (speed 3) (safety 0) (debug 0))
    #'equal)
  #+swank (ql:quickload '(:cl-debug-print :fiveam) :silent t)
  #-swank (set-dispatch-macro-character
           ;; enclose the form with VALUES to avoid being captured by LOOP macro
           #\# #\> (lambda (s c p) (declare (ignore c p)) `(values ,(read s nil nil t)))))
#+swank (cl-syntax:use-syntax cl-debug-print:debug-print-syntax)
#-swank (disable-debugger) ; for CS Academy

;; BEGIN_INSERTED_CONTENTS
(declaim (inline shuffle!))
(defun shuffle! (vector)
  "Destructively shuffles VECTOR by Fisher-Yates algorithm."
  (declare (vector vector))
  (loop for i from (- (length vector) 1) above 0
        for j = (random (+ i 1))
        do (rotatef (aref vector i) (aref vector j)))
  vector)

(defmacro dbg (&rest forms)
  #+swank
  (if (= (length forms) 1)
      `(format *error-output* "~A => ~A~%" ',(car forms) ,(car forms))
      `(format *error-output* "~A => ~A~%" ',forms `(,,@forms)))
  #-swank (declare (ignore forms)))

(defmacro define-int-types (&rest bits)
  `(progn
     ,@(mapcar (lambda (b) `(deftype ,(intern (format nil "UINT~A" b)) () '(unsigned-byte ,b))) bits)
     ,@(mapcar (lambda (b) `(deftype ,(intern (format nil "INT~A" b)) () '(signed-byte ,b))) bits)))
(define-int-types 2 4 7 8 15 16 31 32 62 63 64)

(declaim (inline println))
(defun println (obj &optional (stream *standard-output*))
  (let ((*read-default-float-format* 'double-float))
    (prog1 (princ obj stream) (terpri stream))))

(defconstant +mod+ 1000000007)

;;;
;;; Body
;;;

(defun query (start end &key include exclude)
  (write-char #\?)
  (loop for i from start below end
        unless (eql exclude i)
        do (write-char #\ )
           (princ (+ 1 i)))
  (when include
    (write-char #\ )
    (princ (+ 1 include)))
  (terpri)
  (let ((ans (read-line)))
    (cond ((equal ans "Red") #\R)
          ((equal ans "Blue") #\B)
          (t (error "Huh?")))))

(defun main ()
  (let* ((n (read))
         (left-color (query 0 n))
         (right-color (if (eql left-color #\R) #\B #\R))
         (left-pivot (sb-int:named-let bisect ((left 0) (right n))
                       (if (<= (- right left) 1)
                           left
                           (let ((mid (ash (+ left right) -1)))
                             (if (eql left-color (query mid (+ mid n)))
                                 (bisect mid right)
                                 (bisect left mid))))))
         (res (make-array (* 2 n) :element-type 'base-char :initial-element #\Nul)))
    ;; (dbg left-pivot left-color)
    (setf (aref res left-pivot) left-color
          (aref res (+ left-pivot n)) right-color)
    (dbg res)
    (loop for i from 0 below left-pivot
          do (setf (aref res i)
                   (query (+ 1 left-pivot) (+ left-pivot n) :include i)))
    (dbg res)
    (loop for i from (+ left-pivot n 1) below (* 2 n)
          do (setf (aref res i)
                   (query (+ 1 left-pivot) (+ left-pivot n) :include i)))
    (dbg res)
    (loop for i from (+ left-pivot 1) below (+ left-pivot n)
          do (setf (aref res i)
                   (if (eql #\R (query left-pivot (+ left-pivot n 1) :exclude i))
                       #\B
                       #\R)))
    (format t "! ~A~%" res)))

#-swank (main)

;;;
;;; Test and benchmark
;;;

#+swank
(defun io-equal (in-string out-string &key (function #'main) (test #'equal))
  "Passes IN-STRING to *STANDARD-INPUT*, executes FUNCTION, and returns true if
the string output to *STANDARD-OUTPUT* is equal to OUT-STRING."
  (labels ((ensure-last-lf (s)
             (if (eql (uiop:last-char s) #\Linefeed)
                 s
                 (uiop:strcat s uiop:+lf+))))
    (funcall test
             (ensure-last-lf out-string)
             (with-output-to-string (out)
               (let ((*standard-output* out))
                 (with-input-from-string (*standard-input* (ensure-last-lf in-string))
                   (funcall function)))))))

#+swank
(defun get-clipbrd ()
  (with-output-to-string (out)
    (run-program "C:/msys64/usr/bin/cat.exe" '("/dev/clipboard") :output out)))

#+swank (defparameter *this-pathname* (uiop:current-lisp-file-pathname))
#+swank (defparameter *dat-pathname* (uiop:merge-pathnames* "test.dat" *this-pathname*))

#+swank
(defun run (&optional thing (out *standard-output*))
  "THING := null | string | symbol | pathname

null: run #'MAIN using the text on clipboard as input.
string: run #'MAIN using the string as input.
symbol: alias of FIVEAM:RUN!.
pathname: run #'MAIN using the text file as input."
  (let ((*standard-output* out))
    (etypecase thing
      (null
       (with-input-from-string (*standard-input* (delete #\Return (get-clipbrd)))
         (main)))
      (string
       (with-input-from-string (*standard-input* (delete #\Return thing))
         (main)))
      (symbol (5am:run! thing))
      (pathname
       (with-open-file (*standard-input* thing)
         (main))))))

#+swank
(defun gen-dat ()
  (uiop:with-output-file (out *dat-pathname* :if-exists :supersede)
    (format out "")))

#+swank
(defun bench (&optional (out (make-broadcast-stream)))
  (time (run *dat-pathname* out)))

;; To run: (5am:run! :sample)



Measured memory_bytes: 25644