Python/conversions/roman_to_integer.py
Jasper 3242682473 Create roman_to_integer.py (#1636)
* added roman to integer conversion (LeetCode No. 13)

* updated directory to include Roman to Integer

* Delete DIRECTORY.md

* Update roman_to_integer.py

Co-authored-by: Christian Clauss <cclauss@me.com>
2019-12-21 00:23:15 +01:00

28 lines
923 B
Python

def roman_to_int(roman: str) -> int:
"""
LeetCode No. 13 Roman to Integer
Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999.
https://en.wikipedia.org/wiki/Roman_numerals
>>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500, "MMMCMXCIX": 3999}
>>> all(roman_to_int(key) == value for key, value in tests.items())
True
"""
vals = {"I": 1, "V": 5, "X": 10, "L": 50, "C": 100, "D": 500, "M": 1000}
total = 0
place = 0
while place < len(roman):
if (place + 1 < len(roman)) and (vals[roman[place]] < vals[roman[place + 1]]):
total += vals[roman[place + 1]] - vals[roman[place]]
place += 2
else:
total += vals[roman[place]]
place += 1
return total
if __name__ == "__main__":
import doctest
doctest.testmod()