LeetCode - Decode String(394)

실패

class Solution:
    def decodeString(self, s: str) -> str:
        a = list(s)
        stack = []
        k = [ '[', ']' ]
        
        for i in range(len(a)):
            current = a[i]
            if k.count(current) == 1:
                if len(stack) == 0:
                    stack.append([a[i], i])
        
                if stack[-1][0] != a[i]:
                    start = stack[-1][1]
                    end = i
                    s.replace(''.join(a[start - 1 : end + 1]), ''.join(int(a[start - 1]) * a[start + 1 : end]))
                    stack.pop()
                else:
                    stack.append([a[i], i])
        
        return True