Azim Hossain Tuhin

Roman numerals are a classic system of number representation used in ancient Rome, and they still appear today in clocks, chapters, and outlines. Converting these numerals into modern-day integers is a popular coding problem that helps strengthen your understanding of condition-based logic and iteration in Python.

Objective

The goal of this task is to build a function that takes a Roman numeral string as input and returns its equivalent integer value. This exercise is commonly found in coding interviews and problem-solving platforms, such as LeetCode.

Understanding the Logic

Roman numerals follow a simple pattern where each character maps to a specific value. However, there are special subtraction rules involved. For example, IV is not 1 + 5 = 6, but rather 5 - 1 = 4.

To solve this problem efficiently, we loop through the string and:

• Compare each character with the next one.

• If the current character is smaller than the next, we subtract it.

• Otherwise, we add it.

This logic ensures that subtraction cases like IV, IX, XL, etc., are handled correctly.

Why This Approach Works

• The solution uses a dictionary to store Roman symbols and their integer values.

• A single pass through the input string ensures O(n) time complexity.

• The logic is readable, efficient, and suitable for production-level use or interviews.

Use Case

This kind of problem is useful in:

• Building educational or quiz platforms

• Data conversion utilities

• Improving algorithmic problem-solving skills for developers

Conclusion

Converting Roman numerals to integers is a great way to reinforce your understanding of loops, conditions, and dictionary-based lookups in Python. It’s a clean, real-world use case of algorithmic thinking that translates well into many practical and interview scenarios.