Implement menu parser and serializer

### Menu parser and serializer You are given a restaurant menu stored as plain text, where indentation represents a hierarchy of categories and items. Implement logic to convert between this text format and a tree data structure. #### Text format - The menu is a multi-line string; each non-empty line describes one menu item. - Leading indentation (0 or more groups of two spaces) indicates nesting depth relative to top-level categories. - After the indentation, fields on each line are separated by the `|` character: `<type>|<id>|<name>|<price>` where: - `type` is a string label such as `CATEGORY`, `FOOD`, or `SIDE` (you should not assume only these three types; treat it as an arbitrary string). - `id` is a unique identifier string for this item. - `name` is free text that does not contain the `|` character. - `price` is a decimal number (e.g., `5.99`), or the literal `-` if the item does not have a price (e.g., a category). Example input: ```text CATEGORY|c1|Burgers|- FOOD|f1|Classic Burger|5.99 SIDE|s1|Fries|1.99 FOOD|f2|Veggie Burger|6.49 CATEGORY|c2|Drinks|- FOOD|f3|Cola|1.50 FOOD|f4|Water|1.00 ``` This example represents a hierarchy like `category > food > side`, but in general the depth and item types can vary. #### Tree structure Define a data structure `MenuItem` (language-agnostic) with at least the following fields: - `type`: string - `id`: string - `name`: string - `price`: nullable/optional number (null if the text price is `-`) - `children`: an ordered list/array of `MenuItem` representing nested items Top-level menu items are those with zero indentation. #### Tasks 1. Implement a function (e.g., `parseMenu(text)`) that takes the menu text string and returns the corresponding tree: a list/array of top-level `MenuItem` nodes, each with properly populated `children`. 2. Implement a function (e.g., `serializeMenu(items)`) that takes the tree (the list/array of top-level `MenuItem` nodes) and returns a canonical text representation in exactly the same format as described above. The serializer must: - Use exactly two spaces per level of indentation deeper than a parent. - Use `|` as the field separator. - Output `-` for items whose `price` is null/absent. - Output a depth-first traversal, where all children of a node appear immediately after their parent, in the order stored in `children`. You may assume the input text is always a valid, well-formed tree (no cycles, consistent indentation, and at least one top-level item). Design your parsing and serialization logic to run in O(N) time and O(N) extra space, where N is the number of menu items (lines) in the input.