394. Decode String

class Solution(object):
    def decodeString(self, s):
        """
        :type s: str
        :rtype: str
        """
        stack = []
        for i in s:
            if i != ']':
                stack.append(i)
            else:
                temp = []
                while stack[-1] != '[':
                    t = stack.pop()
                    temp.append(t)
                temp = temp[::-1]
                stack.pop()
                n_l = []
                while stack and stack[-1] in '1234567890':
                    n_l.append(int(stack.pop()))
                n_l = n_l[::-1]
                n = 0
                for i in n_l:
                    n = n * 10 + I
                stack.extend(n*temp)
        return ''.join(stack)