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68 lines
2.4 KiB
Python
68 lines
2.4 KiB
Python
ROMAN = [
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(1000000, "M_"), (900000, "C_M_"), (500000, "D_"), (400000, "C_D_"),
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(100000, "C_"), (90000, "X_C_"), (50000, "L_"), (40000, "X_L_"),
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(10000, "X_"), (9000, "I_X_"), (5000, "V_"), (4000, "I_V_"),
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(1000, "M"), (900, "CM"), (500, "D"), (400, "CD"),
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(100, "C"), (90, "XC"), (50, "L"), (40, "XL"),
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(10, "X"), (9, "IX"), (5, "V"), (4, "IV"), (1, "I")
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]
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def roman_to_int(roman: str) -> int:
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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 = {
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"I": 1, "V": 5, "X": 10, "L": 50, "C": 100, "D": 500, "M": 1000,
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"I_": 1000, "V_": 5000, "X_": 10000, "L_": 50000, "C_": 100000,
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"D_": 500000, "M_": 1000000
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}
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i, total = 0, 0
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while i < len(roman):
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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: int) -> str:
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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 = {"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(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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