# https://leetcode.com/problems/process-string-with-special-operations-i

class Solution:
    def processStr(self, s: str) -> str:
        result = []
        for ch in s:
            match ch:
                case '#':
                    result *= 2
                case '%':
                    result.reverse()
                case '*':
                    if len(result) > 0:
                        result.pop()
                case _:
                    result.append(ch)
        return ''.join(result)