Integer to Roman Explained

Problem Statement

Given an integer num (between 1 and 3999), convert it to a Roman numeral string. Roman numerals use symbols I (1), V (5), X (10), L (50), C (100), D (500), and M (1000), with subtraction rules for cases like IV (4) and IX (9). This problem tests your ability to map numbers to symbols systematically.

Example

Input: num = 1994

Output: "MCMXCIV"

Explanation: 1000 = M, 900 = CM, 90 = XC, 4 = IV.

Code

public class Solution {
    public String intToRoman(int num) {
        int[] values = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
        String[] symbols = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < values.length; i++) {
            while (num >= values[i]) {
                sb.append(symbols[i]);
                num -= values[i];
            }
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        Solution sol = new Solution();
        System.out.println(sol.intToRoman(1994)); // "MCMXCIV"
    }
}
            

def int_to_roman(num):
    values = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
    symbols = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"]
    result = ""
    for i in range(len(values)):
        while num >= values[i]:
            result += symbols[i]
            num -= values[i]
    return result

# Example usage
print(int_to_roman(1994))  # "MCMXCIV"
            

function intToRoman(num) {
    const values = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
    const symbols = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
    let result = "";
    for (let i = 0; i < values.length; i++) {
        while (num >= values[i]) {
            result += symbols[i];
            num -= values[i];
        }
    }
    return result;
}

// Example usage
console.log(intToRoman(1994)); // "MCMXCIV"
            

Explanation

• Define arrays for Roman numeral values and their corresponding symbols, including subtraction cases (e.g., CM = 900).
• Iterate through the values from largest to smallest.
• For each value, append its symbol and subtract it from num as many times as possible.
• Continue until num becomes 0.
• Return the resulting string.

Note