snobol, 104 bytes

Result

AC

Duration

767ms

Code [DL]

	T = TRIM(INPUT)
F	OUTPUT = T
	IDENT('',K = TRIM(INPUT))	:S(F)
	OUTPUT = K DUPL(1,SIZE(T) - SIZE(K))
END

stdin

                                      T           
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                       K                          

stdout

                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                                      T
                       K111111111111111

stderr

strace