LeetCode 385. Mini Parser · Shell32

LeetCode 385. Mini Parser · Shell32

Given a nested list of integers represented as a string, implement a parser to deserialize it.

Each element is either an integer, or a list – whose elements may also be integers or other lists.

Note: You may assume that the string is well-formed:

• String is non-empty.
• String does not contain white spaces.
• String contains only digits 0-9, [, - ,, ].

Example 1:

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> Given s = "324", > > You should return a NestedInteger object which contains a single integer 324. > >

Example 2:

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> Given s = "[123,[456,[789]]]", > > Return a NestedInteger object containing a nested list with 2 elements: > > 1. An integer containing value 123. > 2. A nested list containing two elements: > i. An integer containing value 456. > ii. A nested list with one element: > a. An integer containing value 789. >

题目要求把一个合法的字符串转换为对应的嵌套的数据格式, 一开始我想使用递归, 但是在处理嵌套的问题上遇到了麻烦, 所以改为使用栈来做.

把每一层嵌套视为栈的一个元素, 每遇到一个[就入栈一个新的NestedInteger, 然后遇到数字就把它加入到栈顶的NestedInteger中去, 遇到]就把栈顶的元素弹出, 加入到新的栈顶中, 如果弹出栈顶后栈为空说明处理结束.

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