385 - Mini Parser.

Medium

Given a string s represents the serialization of a nested list, implement a parser to deserialize it and return the deserialized NestedInteger.

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

Example 1:

Input: s = "324"

Output: 324

Explanation: You should return a NestedInteger object which contains a single integer 324.

Example 2:

Input: s = "[123,[456,789]]"

Output: [123,[456,789]]

Explanation: Return a NestedInteger object containing a nested list with 2 elements:

• An integer containing value 123.

• 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

Constraints:

• <code>1 <= s.length <= 5 * 10⁴</code>

• s consists of digits, square brackets "[]", negative sign '-', and commas ','.

• s is the serialization of valid NestedInteger.

• All the values in the input are in the range <code>-10⁶, 10⁶</code>.