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03889613bc
* add integer to roman function simply added fastest method i found. * Rename roman_to_integer.py to roman_numerals.py * Update roman_numerals.py * Update roman_numerals.py Co-authored-by: Christian Clauss <cclauss@me.com>
60 lines
1.7 KiB
Python
60 lines
1.7 KiB
Python
def roman_to_int(roman: str) -> int:
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"""
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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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https://en.wikipedia.org/wiki/Roman_numerals
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>>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500, "MMMCMXCIX": 3999}
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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 = {"I": 1, "V": 5, "X": 10, "L": 50, "C": 100, "D": 500, "M": 1000}
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total = 0
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place = 0
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while place < len(roman):
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if (place + 1 < len(roman)) and (vals[roman[place]] < vals[roman[place + 1]]):
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total += vals[roman[place + 1]] - vals[roman[place]]
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place += 2
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else:
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total += vals[roman[place]]
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place += 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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Given a integer, convert it to an roman numeral.
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https://en.wikipedia.org/wiki/Roman_numerals
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>>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500, "MMMCMXCIX": 3999}
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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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ROMAN = [
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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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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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