Validate a JSON-like string

Q: Validate a JSON-like string

This question evaluates parsing and string-processing skills, focusing on structural validation of JSON-like text including matching and nesting of brackets and correct handling of quoted strings with escape sequences.

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Q: What difficulty level is this interview question?

This is a medium difficulty Coding & Algorithms question, commonly asked during Onsite rounds at Microsoft.

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This question is commonly asked for Software Engineer candidates at Microsoft during technical interviews.

Question

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Problem

You are given a string s that is intended to be a JSON text. Implement a function isValidJsonStructure(s) -> bool that checks structural validity of the JSON with the following simplified rules:

Rules to validate

After ignoring leading/trailing whitespace, the text must start and end with matching outer brackets:
- either { ... } or [ ... ] .
Brackets must be properly nested and balanced :
- curly braces {}
- square brackets []
JSON strings are delimited by double quotes "..." .
- While inside a string, any bracket characters ( { } [ ] ) must be ignored for nesting purposes.
- A quote preceded by an odd number of backslashes is escaped (e.g., \" closes? no; \" contains an escaped quote). In other words, " does not end a string.
You do not need to validate JSON key/value grammar (colons, commas, numbers, true/false/null , etc.). Only validate the above structural properties.

Input/Output

Input: string s
Output: true if structurally valid per the rules; otherwise false .

Constraints

1 <= len(s) <= 1e5

Examples

"{\"a\":[1,2,3]}" → true
"{[}]" → false (bad nesting)
"{\"x\":\"[}\"}" → true (brackets inside a string are ignored)
"{\"a\":\"unterminated}" → false (unclosed string)