leetcode385

class Solution:
    def deserialize(self, s: str) -> NestedInteger:
        
        if s[0] != '[':
            return NestedInteger(int(s))
        
        stack = []
        # num为数字，sign为符号为，is_num为前一个是否为数字
        num, sign, is_num = 0, 1, False
        
        for c in s:
            if c.isdigit():
                num = num * 10 + int(c)
                is_num = True
            elif c == '-':
                sign = -1
            elif c == '[':
                stack.append(NestedInteger())
            elif c == ',' or c == ']':
                # 把刚才遇到的数字append进去
                if is_num:
                    cur_list = stack.pop()
                    cur_list.add(NestedInteger(sign * num))
                    stack.append(cur_list)
                num, sign, is_num = 0, 1, False

                # 此时为嵌套列表
                if c == ']' and len(stack) > 1:
                    cur_list = stack.pop()
                    stack[-1].add(cur_list)

        return stack[0]

参考：https://leetcode-cn.com/problems/mini-parser/solution/python3ti-mu-bu-nan-zhi-xu-li-qing-luo-ji-by-salti/

一般来说，这种差评如潮的题目，又可能不是题目难，而是题目描述不清楚，对人有误导。本题似乎就存在这个问题。