Resolved: Replace two adjacent duplicate characters in string with the next character in alphabet

In this post, we will see how to resolve Replace two adjacent duplicate characters in string with the next character in alphabet

Question:

I want to write a function, that will find the first occurrence of two adjacent characters that are the same, replace them with a single character that is next in the alphabet and go over the string until there are no duplicates left. In case of “zz” it should go in a circular fashion back to “a”. The string can only include characters a-z, that is, no capital letters or non-alphabetical characters. I have written a function that does it, but it is not effective enough for a very long string.
So for example if s = 'aabbbc' the function should work like aabbbc –> bbbbc –> cbbc –> ccc and finally return dc. How can I make it more efficient?
Edit: for example if s = 'ab'*10**4 + 'cc'*10**4 + 'dd'*10**4 this function is taking a lot of time.

Best Answer:

As a trivial optimisation: instead of the hard reset i = 1, you can use a softer reset i = i-1. Indeed, if there was no duplicate between 1 and i before the transformation, then there still won’t be any duplicate between 1 and i-1 after the transformation.

If you have better answer, please add a comment about this, thank you!

Source: Stackoverflow.com