1 files changed, 69 insertions, 0 deletions
diff --git a/challenge-227/sgreen/python/ch-2.py b/challenge-227/sgreen/python/ch-2.py
new file mode 100755
index 0000000000..30aa4b9995
--- /dev/null
+++ b/challenge-227/sgreen/python/ch-2.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def from_roman(roman):
+    mapping = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
+    digits = [mapping[s] for s in roman]
+
+    number = 0
+    for i, v in enumerate(digits):
+        if i < len(digits)-1 and v < digits[i+1]:
+            number -= v
+        else:
+            number += v
+
+    return number
+
+
+def to_roman(number):
+    if number == 0:
+        return 'nulla'
+    elif number > 3999 or number < 0:
+        return 'non potest'
+    elif type(number) == float:
+        if not number.is_integer():
+            return 'non potest'
+        number = int(number)
+
+    mapping = [
+        ['', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX', ],
+        ['', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX', 'XC', ],
+        ['', 'C', 'CC', 'CCC', 'CD', 'D', 'DC', 'DCC', 'DCCC', 'CM', ],
+        ['', 'M', 'MM', 'MMM', ],
+    ]
+
+    # Convert it into a string
+    roman = ''
+    number = str(number)
+
+    # Iterate in reverse
+    for i, d in enumerate(number[::-1]):
+        roman = mapping[i][int(d)] + roman
+
+    return roman
+
+
+def main(roman1, oper, roman2):
+    number1 = from_roman(roman1)
+    number2 = from_roman(roman2)
+
+    if oper == '+':
+        number = number1 + number2
+    elif oper == '-':
+        number = number1 - number2
+    elif oper == '*' or oper == '×':
+        number = number1 * number2
+    elif oper == '/' or oper == '÷':
+        number = number1 / number2
+    elif oper == '**':
+        number = number1 ** number2
+    else:
+        raise ValueError(f"Unknown operator: '{oper}'")
+
+    print(to_roman(number))
+
+
+if __name__ == '__main__':
+    main(*sys.argv[1:])