Practice/Meta/Leetcode 2633. Convert Object to JSON String

Leetcode 2633. Convert Object to JSON String

CodingOptional

Problem

Write a function that converts a data structure into a valid JSON-formatted string. Your serializer must handle primitive types (numbers, strings, booleans, null), arrays, and objects (dictionaries/maps). The output string must conform to JSON standards, including proper escaping of special characters within strings.

You cannot use built-in JSON serialization functions like JSON.stringify() or json.dumps(). The goal is to implement the serialization logic from scratch.

Requirements

1. Serialize primitive values: numbers, strings, booleans, and null
2. Serialize arrays (lists) by wrapping elements in square brackets with comma separation
3. Serialize objects (dictionaries) by wrapping key-value pairs in curly braces
4. Escape special characters in strings: quotes ("), backslashes (\), and control characters (newline, tab, etc.)
5. Handle nested structures recursively
6. Output must be valid JSON without extra whitespace

Constraints

• The input will only contain valid JSON-serializable data types
• Nesting depth will not exceed 100 levels
• String length will not exceed 10,000 characters
• Object keys are always strings
• Time complexity should be O(n) where n is the total number of elements
• Space complexity should be O(d) where d is the maximum nesting depth

Examples

Example 1:

Input: \{"name": "Bob", "age": 25\} Output: "\{\"name\":\"Bob\",\"age\":25\}" Explanation: Object with string and number values serialized with proper formatting

Example 2:

Input: [1, 2, [3, 4]] Output: "[1,2,[3,4]]" Explanation: Nested array structure with proper bracket nesting

Example 3:

Input: \{"text": "Quote: \"Hello\""\} Output: "\{\"text\":\"Quote: \\\"Hello\\\"\"\}" Explanation: Double quotes within string values must be escaped with backslashes