Changes

Through the profile, we can see that the most cost of the runtime is 'grep()' and 'convert_char_to_string()' functions. <br>

''' Basic Variables '''

First, I look at function 'convert_char_to_string()'. I think it's no necessary to use this function, so I remove it.<br>

[[File:StringremoveJPG.JPG|650px]]

'''Serial grep method'''

Simple? But to parallel it is not that simple...<br>

'''Parallel grep idea'''