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88 lines
2.3 KiB
Python
88 lines
2.3 KiB
Python
ROMAN = [
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(1000000, "M_"),
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(900000, "C_M_"),
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(500000, "D_"),
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(400000, "C_D_"),
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(100000, "C_"),
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(90000, "X_C_"),
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(50000, "L_"),
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(40000, "X_L_"),
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(10000, "X_"),
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(9000, "I_X_"),
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(5000, "V_"),
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(4000, "I_V_"),
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(1000, "M"),
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(900, "CM"),
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(500, "D"),
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(400, "CD"),
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(100, "C"),
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(90, "XC"),
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(50, "L"),
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(40, "XL"),
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(10, "X"),
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(9, "IX"),
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(5, "V"),
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(4, "IV"),
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(1, "I"),
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]
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def roman_to_int(roman):
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"""
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Convert a Roman numeral to an integer, supporting Vinculum notation
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(underscore _ represents 1000 times).
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LeetCode No. 13 Roman to Integer:
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Given a Roman numeral, convert it to an integer.
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Input is guaranteed to be within the range from 1 to 3999.
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Reference: https://en.wikipedia.org/wiki/Roman_numerals
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>>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500,
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... "MMMCMXCIX": 3999, "I_V_": 4000, "X_": 10000, "M_": 1000000}
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>>> all(roman_to_int(key) == value for key, value in tests.items())
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True
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"""
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vals = {roman: arabic for arabic, roman in ROMAN}
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# Convert the list of tuples to a dictionary
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i, total = 0, 0
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while i < len(roman):
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# 先匹配 2 个字符的罗马数字（如 I_、X_）
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if i + 1 < len(roman) and roman[i : i + 2] in vals:
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total += vals[roman[i : i + 2]]
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i += 2
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else:
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total += vals[roman[i]]
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i += 1
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return total
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def int_to_roman(number):
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"""
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Convert an integer to a Roman numeral, supporting Vinculum notation
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(underscore _ represents 1000 times).
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Given an integer, convert it to a Roman numeral.
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Reference: https://en.wikipedia.org/wiki/Roman_numerals
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>>> tests = {3: "III", 154: "CLIV", 1009: "MIX", 2500: "MMD", 3999: "MMMCMXCIX"}
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>>> all(int_to_roman(value) == key for key, value in tests.items())
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True
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"""
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if not isinstance(number, int) or number < 1:
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raise ValueError("Input must be a positive integer greater than 0")
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result = []
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for arabic, roman in ROMAN:
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factor, number = divmod(number, arabic)
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result.append(roman * factor)
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if number == 0:
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break
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return "".join(result)
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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