Microsoft Intern interview questions

Standard leetcode like questions, where I had to write code on the whiteboard and explain my logic.

There is a string of length N made only of letters "a". Whenever there are two identical adjacent letters (e.g. "aa"), they can be transformed into a single letter that is the next letter of the alphabet. For example, "aa" can be transformed into "b" and "e" into "t" However, "zz" cannot be further transformed.