exercicio 13 resolvido com python

13-roman_to_integer/python/13.py

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