Integer to Roman Leetcode Solution

In this post, we are going to solve the Integer to Roman Leetcode Solution problem of Leetcode. This Leetcode problem is done in many programming languages like C++, Java, and Python.

Problem

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             1000

For example, 2 is written as II in Roman numeral, just two one‘s added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II.

Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used:

• I can be placed before V (5) and X (10) to make 4 and 9. 
• X can be placed before L (50) and C (100) to make 40 and 90. 
• C can be placed before D (500) and M (1000) to make 400 and 900.

Given an integer, convert it to a roman numeral.

Example 1:

Input: num = 3
Output: "III"
Explanation: 3 is represented as 3 ones.

Example 2:

Input: num = 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.

Example 3:

Input: num = 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.

Constraints:

• 1 <= num <= 3999

Now, let’s see the leetcode solution of Integer to Roman Leetcode Solution.

Integer to Roman Leetcode Solution in Python

class Solution(object):
    def intToRoman(self, num):
        values = [ 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 ]
        numerals = [ "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" ]
        res = ""
        for i, v in enumerate(values):
            res += (num//v) * numerals[i]
            num %= v
        return res

Integer to Roman Leetcode Solution in CPP

class Solution {
public:
    string intToRoman(int num) 
    {
        string res;
        string sym[] = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
        int val[] = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
        
        for(int i=0; num != 0; i++)
        {
            while(num >= val[i])
            {
                num -= val[i];
                res += sym[i];
            }
        }
        
        return res;
    }
};

Integer to Roman Leetcode Solution in Java

class Solution {
    public String intToRoman(int num) {
            int[] values = {1000,900,500,400,100,90,50,40,10,9,5,4,1};
            String[] strs = {"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]) {
                    num -= values[i];
                    sb.append(strs[i]);
                }
            }
            return sb.toString();
    }
}

Note: This problem Integer to Roman is generated by Leetcode but the solution is provided by Chase2learn This tutorial is only for Educational and Learning purposes.

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