85 lines
2.8 KiB
Python
85 lines
2.8 KiB
Python
# Roman numerals are represented by seven different symbols:
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# I, V, X, L, C, D and M.
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#
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# Symbol Value
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# I 1
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# V 5
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# X 10
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# L 50
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# C 100
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# D 500
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# M 1000
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#
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# For example, 2 is written as II in Roman numeral, just two ones added
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# together. 12 is written as XII, which is simply X + II. The number 27 is
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# written as XXVII, which is XX + V + II.
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#
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# Roman numerals are usually written largest to smallest from left to right.
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# However, the numeral for four is not IIII. Instead, the number four is
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# written as IV. Because the one is before the five we subtract it making four.
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# The same principle applies to the number nine, which is written as IX. There
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# are six instances where subtraction is used:
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#
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# I can be placed before V (5) and X (10) to make 4 and 9.
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# X can be placed before L (50) and C (100) to make 40 and 90.
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# C can be placed before D (500) and M (1000) to make 400 and 900.
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#
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# Given a roman numeral, convert it to an integer.
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#
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def romanToInt(s: str) -> int:
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resultado: int = 0
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for index in range(len(s)):
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match s[index]:
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case "I":
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if (index < (len(s) - 1)) and (
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s[index + 1] == "V" or s[index + 1] == "X"
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):
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continue
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resultado += 1
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case "V":
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if s[index - 1] == "I" and index > 0:
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resultado += 4
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continue
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else:
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resultado += 5
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case "X":
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if (index < (len(s) - 1)) and (
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s[index + 1] == "L" or s[index + 1] == "C"
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):
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continue
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if s[index - 1] == "I" and index > 0:
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resultado += 9
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continue
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else:
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resultado += 10
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case "L":
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if s[index - 1] == "X" and index > 0:
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resultado += 40
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continue
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else:
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resultado += 50
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case "C":
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if (index < (len(s) - 1)) and (
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s[index + 1] == "D" or s[index + 1] == "M"
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):
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continue
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if s[index - 1] == "X" and index > 0:
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resultado += 90
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continue
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else:
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resultado += 100
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case "D":
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if s[index - 1] == "C" and index > 0:
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resultado += 400
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continue
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else:
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resultado += 500
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case "M":
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if s[index - 1] == "C" and index > 0:
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resultado += 900
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continue
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else:
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resultado += 1000
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return resultado
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