Update roman_numerals.py

Author: lighting9999

conversions/roman_numerals.py

@@ -25,8 +25,6 @@
     (4, "IV"),
     (1, "I"),
 ]
-
-
 def roman_to_int(roman: str) -> int:
     """
     Convert a Roman numeral to an integer, supporting Vinculum notation
@@ -42,44 +40,27 @@ def roman_to_int(roman: str) -> int:
     >>> 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,
-        "I_": 1000,
-        "V_": 5000,
-        "X_": 10000,
-        "L_": 50000,
-        "C_": 100000,
-        "D_": 500000,
-        "M_": 1000000,
-    }
+    vals = dict(ROMAN)  # Convert the list of tuples to a dictionary
 
     i, total = 0, 0
     while i < len(roman):
-        if i + 1 < len(roman) and roman[i : i + 2] in vals:
-            total += vals[roman[i : i + 2]]
+        # Check for 2-character symbols first (like I_ or X_)
+        if i + 1 < len(roman) and roman[i:i+2] in vals:
+            total += vals[roman[i:i+2]]
             i += 2
         else:
             total += vals[roman[i]]
             i += 1
     return total
-
-
 def int_to_roman(number: int) -> str:
     """
     Convert an integer to a Roman numeral, supporting Vinculum notation
     (underscore _ represents 1000 times).
 
     Given an integer, convert it to a Roman numeral.
 
-    Reference:https://en.wikipedia.org/wiki/Roman_numerals
-    >>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500,
-    ...          "MMMCMXCIX": 3999, "I_V_": 4000, "X_": 10000, "M_": 1000000}
+    Reference: https://en.wikipedia.org/wiki/Roman_numerals
+    >>> tests = {3: "III", 154: "CLIV", 1009: "MIX", 2500: "MMD", 3999: "MMMCMXCIX"}
     >>> all(int_to_roman(value) == key for key, value in tests.items())
     True
     """
@@ -93,9 +74,7 @@ def int_to_roman(number: int) -> str:
         if number == 0:
             break
     return "".join(result)
-
-
+    
 if __name__ == "__main__":
     import doctest
-
     doctest.testmod()