perl, 53 bytes

Result

AC

Duration

665ms

Code [DL]

$/=0;$_=<>;s/([^T]{50})./$1T/g;0while s/K /KK/g;print

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                    
        KKKKKKKKKKKKKKKKKKKKKT                    

stderr

strace