an algorithm that could replace the same 3 letters to previous one or delete
For a given string that only contains alphabet characters a-z, if 3 or more consecutive characters are identical, remove them from the string. Repeat this process until there is no more than 3 identical characters sitting besides each other.
please refer to the method removeConsecutiveStr
Instead of removing the consecutively identical characters, replace them with a single character that comes before it alphabetically.
please refer to the method replaceConsecutiveChars
use Junit to auto test the functions