Roman to Integer
Convert a Roman numeral string to an integer.
I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Subtractive: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900.
Example:
III
3
- The input string
IIIis analyzed from left to right to determine the integer equivalent of each Roman numeral. - Since each
Ihas a value of 1 and there are no subtractive cases in the input, we simply add the values of the threeIs together: 1+1+1=3. - The final output is the sum calculated in the previous step, which is 3.
Constraints:
- 1 <= len(s) <= 15
- s is a valid Roman numeral in [1, 3999]
Background Knowledge
The problem involves converting Roman numerals to integers. Roman numerals are a numeral system that originated in ancient Rome, where numbers are represented by letters such as I, V, X, L, C, D, and M. Each letter has a specific value: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, and M = 1000. In addition to these basic values, Roman numerals also use a subtractive notation, where a smaller number placed before a larger number means subtraction. For example, IV = 4 (5 - 1) and IX = 9 (10 - 1).
To solve this problem, it's essential to understand the rules of Roman numerals, including the subtractive notation. The subtractive notation is used to represent numbers that are not a simple addition of the basic values. For instance, the number 4 is represented as IV, which is 5 (V) minus 1 (I). Similarly, the number 9 is represented as IX, which is 10 (X) minus 1 (I). Understanding these rules will help you develop an algorithm to convert Roman numerals to integers.
The problem can be approached using a combination of string manipulation and arithmetic operations. Since the input is a string of Roman numerals, you'll need to iterate over the string, identify the values of each numeral, and apply the subtractive notation rules to calculate the final integer value. This involves using conditional statements to handle the different cases, such as when a smaller numeral appears before a larger one, indicating subtraction.
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