New feature: Support for converting numbers in a larger range.

To extend the current solution to support even larger ranges of numbers beyond 1,000,000, we can enhance the Roman numeral system to use additional notation for larger values. In Roman numerals, there is no native representation for numbers greater than 1,000,000.

Author: lighting9999

conversions/roman_numerals.py

@@ -1,61 +1,56 @@
 ROMAN = [
-    (1000, "M"),
-    (900, "CM"),
-    (500, "D"),
-    (400, "CD"),
-    (100, "C"),
-    (90, "XC"),
-    (50, "L"),
-    (40, "XL"),
-    (10, "X"),
-    (9, "IX"),
-    (5, "V"),
-    (4, "IV"),
-    (1, "I"),
+    (1000000, "M_"), (900000, "C_M_"), (500000, "D_"), (400000, "C_D_"),
+    (100000, "C_"), (90000, "X_C_"), (50000, "L_"), (40000, "X_L_"),
+    (10000, "X_"), (9000, "I_X_"), (5000, "V_"), (4000, "I_V_"),
+    (1000, "M"), (900, "CM"), (500, "D"), (400, "CD"),
+    (100, "C"), (90, "XC"), (50, "L"), (40, "XL"),
+    (10, "X"), (9, "IX"), (5, "V"), (4, "IV"), (1, "I")
 ]
-
-
 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}
+    Convert a Roman numeral to an integer, supporting Vinculum notation (underscore _ represents 1000 times).
+    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 
+ ​    >>> all(roman_to_int(key) == value for key, value in tests.items())
+    >>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500, "MMMCMXCIX": 3999, "I_V_": 4000, "X_": 10000, "M_": 1000000}
     >>> 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
+    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
+    }
+    i, total = 0, 0
+    while i < len(roman):
+        if i + 1 < len(roman) and (roman[i:i+2] in vals):  # 处理 `_` 记法
+            total += vals[roman[i:i+2]]
+            i += 2
         else:
-            total += vals[roman[place]]
-            place += 1
+            total += vals[roman[i]]
+            i += 1
     return total
-
-
-def int_to_roman(number: int) -> str:
+    def int_to_roman(number: int) -> str:
     """
-    Given a integer, convert it to an roman numeral.
-    https://en.wikipedia.org/wiki/Roman_numerals
-    >>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500, "MMMCMXCIX": 3999}
+   Convert an integer to a Roman numeral, supporting Vinculum notation (underscore _ represents 1000 times).
+    Given a integer, convert it to an roman numeral. 
+ ​    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}
     >>> all(int_to_roman(value) == key for key, value in tests.items())
     True
     """
+    if not isinstance(number, int) or number < 1:
+        raise ValueError("Input must be a positive integer greater than 0")
+
     result = []
     for arabic, roman in ROMAN:
-        (factor, number) = divmod(number, arabic)
+        factor, number = divmod(number, arabic)
         result.append(roman * factor)
         if number == 0:
-            break
+        reak
     return "".join(result)
 
-
 if __name__ == "__main__":
     import doctest
-
     doctest.testmod()