题目：

题解：

class Solution:
    def decodeString(self, s: str) -> str:
        stk = []
        for ss in s:
            # 不是"]"，照单全收，进栈
            if ss!="]":
                stk.append(ss)
            else:
                # 遇到"]",把"[]"裹起来的单词取出，记为word
                word = ""
                while stk[-1]!="[":
                    word = stk.pop() + word
                # 弹出"["
                stk.pop()
                # 因为会有大于10的次数，所以再写一个while，得到次数，如100
                cnt = 0
                t = 1
                while len(stk) > 0 and ord("0") <= ord(stk[-1]) <=ord("9"):
                    cnt += int(stk.pop()) * t
                    t *= 10
                # 得到重复的字符串后，继续压入栈
                _s = cnt * word
                stk.extend(list(_s))
                #for _ss in _s:
                #    stk.append(_ss)

        return "".join(stk)