【leetcode】394. Decode String

题目如下：

解题思路：这种题目和四则运算，去括号的题目很类似。解法也差不多。

代码如下：

class Solution(object):
    def decodeString(self, s):
        """
        :type s: str
        :rtype: str
        """
        stack = []
        for i in s:
            if i != ']':
                stack.append(i)
                continue
            repeatStr = ''
            while len(stack) > 0:
                v = stack.pop(-1)
                if v == '[':
                    break
                repeatStr = v + repeatStr
            times = ''
            while len(stack) > 0:
                v = stack.pop(-1)
                if v == ']':
                    break
                elif v == '[' or (v >= 'a' and v <= 'z'):
                    stack.append(v)
                    break
                times = v + times
            repeatStr *= int(times)
            stack += list(repeatStr)
        return ''.join(stack)