clisp-sbcl, 150 bytes

Result

AC

Duration

1875ms

Code [DL]

(defun m(u k i)(let((c(read-char))(j(mod(1+ i)51)))(princ(or k(= u i)c))(case c(#\T(m i k j))(#\K(m u c j))(t(or(if k(= u i))(m u k j))))))(m 0 nil 1)

stdin

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                  K                               

stdout

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                  KKKKKKKKKKKKKKKK

stderr

Unhandled UNDEFINED-FUNCTION in thread #<SB-THREAD:THREAD "main thread" RUNNING
                                          {10005205B3}>:
  The function COMMON-LISP-USER::MAIN is undefined.

Backtrace for: #<SB-THREAD:THREAD "main thread" RUNNING {10005205B3}>
0: ("undefined function")
1: (SB-INT:SIMPLE-EVAL-IN-LEXENV (APPLY (QUOTE MAIN) ROSWELL:*ARGV*) #<NULL-LEXENV>)
2: (SB-INT:SIMPLE-EVAL-IN-LEXENV (ROSWELL:QUIT (APPLY (QUOTE MAIN) ROSWELL:*ARGV*)) #<NULL-LEXENV>)
3: (EVAL-TLF (ROSWELL:QUIT (APPLY (QUOTE MAIN) ROSWELL:*ARGV*)) NIL NIL)
4: ((LABELS SB-FASL::EVAL-FORM :IN SB-INT:LOAD-AS-SOURCE) (ROSWELL:QUIT (APPLY (QUOTE MAIN) ROSWELL:*ARGV*)) NIL)
5: (SB-INT:LOAD-AS-SOURCE #<CONCATENATED-STREAM :STREAMS NIL {1002C3B143}> :VERBOSE NIL :PRINT NIL :CONTEXT "loading")
6: ((FLET SB-FASL::THUNK :IN LOAD))
7: (SB-FASL::CALL-WITH-LOAD-BINDINGS #<CLOSURE (FLET SB-FASL::THUNK :IN LOAD) {7F69D2E974FB}> #<CONCATENATED-STREAM :STREAMS NIL {1002C3B143}>)
8: ((FLET SB-FASL::LOAD-STREAM :IN LOAD) #<CONCATENATED-STREAM :STREAMS NIL {1002C3B143}> NIL)
9: (LOAD #<CONCATENATED-STREAM :STREAMS NIL {1002C3B143}> :VERBOSE NIL :PRINT NIL :IF-DOES-NOT-EXIST T :EXTERNAL-FORMAT :DEFAULT)
10: ((FLET ROSWELL::BODY :IN ROSWELL:SCRIPT) #<SB-SYS:FD-STREAM for "file /volume/CODE" {1002C37D53}>)
11: (ROSWELL:SCRIPT "/volume/CODE")
12: (ROSWELL:RUN ((:EVAL "(ros:quicklisp)") (:SCRIPT "/volume/CODE") (:QUIT NIL)))
13: (SB-INT:SIMPLE-EVAL-IN-LEXENV (ROSWELL:RUN (QUOTE ((:EVAL "(ros:quicklisp)") (:SCRIPT "/volume/CODE") (:QUIT NIL)))) #<NULL-LEXENV>)
14: (EVAL (ROSWELL:RUN (QUOTE ((:EVAL "(ros:quicklisp)") (:SCRIPT "/volume/CODE") (:QUIT NIL)))))
15: (SB-IMPL::PROCESS-EVAL/LOAD-OPTIONS ((:EVAL . "(progn #-ros.init(cl:load \"/usr/local/etc/roswell/init.lisp\"))") (:EVAL . "(ros:run '((:eval\"(ros:quicklisp)\")(:script \"/volume/CODE\")(:quit ())))")))
16: (SB-IMPL::TOPLEVEL-INIT)
17: ((FLET SB-UNIX::BODY :IN SAVE-LISP-AND-DIE))
18: ((FLET "WITHOUT-INTERRUPTS-BODY-7" :IN SAVE-LISP-AND-DIE))
19: ((LABELS SB-IMPL::RESTART-LISP :IN SAVE-LISP-AND-DIE))

unhandled condition in --disable-debugger mode, quitting

strace