20240627 2734 - Medium - Greedy

2734. Lexicographically Smallest String After Substring Operation

class Solution:
    def smallestString(self, s: str) -> str:
        res = ""
        i = 0
        while i < len(s):
            if s[i] == "a":
                if i == len(s) -1:
                    res += "z"
                else:
                    res += "a"
            else:
                while i < len(s):
                    if s[i] == "a":
                        res += s[i:]
                        break
                    else:
                        res += chr(ord(s[i]) - 1)
                        i += 1
                break
            i += 1
        return res