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Validate JSON Payloads
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Validate JSON Payloads

HardPython

Problem

How would you implement a function to validate if a given string represents a valid JSON payload?

Implement is_valid_json(s) without using a JSON parsing library. Return True only when the complete input is one valid JSON value, followed only by whitespace. Support objects, arrays, strings, numbers, true, false, and null.

Input is a string. Output is a boolean. Reject malformed escape sequences, invalid numbers, missing delimiters, trailing characters, and unescaped control characters. Duplicate object keys are allowed.

Constraints

  • 0 <= len(s) <= 10^4
  • The input contains ordinary Unicode characters
  • Nesting depth is at most 100
  • Whitespace is limited to space, tab, carriage return, and newline
  • Duplicate object keys are allowed

Function Signature

def is_valid_json(s):
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