159 lines
4.2 KiB
Python
159 lines
4.2 KiB
Python
# Programs are to validate JSON according to the JSON spec (https://www.json.org/), with the exception that you may assume that the string will consist entirely of the classic printable ASCII characters (codepoints 32-127, horizontal tabs, and newlines).
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# You may additionally assume that the input will not be nested more than 16 levels.
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def entry(string):
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if string == "":
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return True
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elif string[0] == '{':
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return entry_object(string)
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elif string[0] == '[':
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return entry_array(string)
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elif string[0] == '"':
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return entry_string(string)
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elif string[0] in '-0123456789':
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return entry_number(string)
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elif string[0] == 't':
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return entry_true(string)
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elif string[0] == 'f':
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return entry_false(string)
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elif string[0] == 'n':
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return entry_null(string)
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else:
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return False
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def entry_object(string):
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if string[0] != '{':
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return False
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string = string[1:]
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if string[0] == '}':
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return True
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while True:
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if not entry_string(string):
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return False
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if not entry_colon(string):
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return False
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if not entry(string):
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return False
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if string[0] == '}':
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return True
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if not entry_comma(string):
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return False
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def entry_array(string):
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if string[0] != '[':
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return False
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string = string[1:]
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if string[0] == ']':
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return True
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while True:
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if not entry(string):
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return False
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if string[0] == ']':
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return True
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if not entry_comma(string):
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return False
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def entry_string(string):
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if string[0] != '"':
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return False
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string = string[1:]
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while True:
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if string[0] == '"':
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return True
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if string[0] == '\\':
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string = string[1:]
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if string[0] == 'u':
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string = string[1:]
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if not string[0] in '0123456789abcdef':
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return False
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string = string[1:]
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if not string[0] in '0123456789abcdef':
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return False
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string = string[1:]
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if not string[0] in '0123456789abcdef':
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return False
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string = string[1:]
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if not string[0] in '0123456789abcdef':
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return False
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string = string[1:]
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elif string[0] == '"':
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pass
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elif string[0] == '\\':
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pass
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elif string[0] == '/':
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pass
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elif string[0] == 'b':
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pass
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elif string[0] == 'f':
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pass
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elif string[0] == 'n':
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pass
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elif string[0] == 'r':
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pass
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elif string[0] == 't':
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pass
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else:
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return False
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else:
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string = string[1:]
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def entry_number(string):
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if string[0] not in '-0123456789':
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return False
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string = string[1:]
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if string[0] == '.':
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string = string[1:]
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if string[0] not in '0123456789':
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return False
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string = string[1:]
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if string[0] in 'eE':
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string = string[1:]
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if string[0] in '+-':
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string = string[1:]
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if string[0] not in '0123456789':
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return False
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string = string[1:]
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if string[0] not in '0123456789':
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return False
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string = string[1:]
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return True
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def entry_colon(string):
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if string[0] != ':':
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return False
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string = string[1:]
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return True
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def entry_comma(string):
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if string[0] != ',':
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return False
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string = string[1:]
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return True
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def entry_true(string):
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if string[0:4] != 'true':
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return False
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string = string[4:]
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return True
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def entry_false(string):
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if string[0:5] != 'false':
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return False
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string = string[5:]
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return True
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def entry_null(string):
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if string[0:4] != 'null':
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return False
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string = string[4:]
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return True
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def main():
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string = input()
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if entry(string):
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print("Valid JSON")
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else:
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print("Invalid JSON")
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if __name__ == "__main__":
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main()
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