Coding Challenge Practice - Question 79

Source: Dev.to

Problem Description

The task is to implement a function that converts integers to Roman numerals.

Approach

Roman numerals are built from largest to smallest. Specific numbers are represented by symbols; a combination is used to form other numbers.

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"];

To convert a number, keep subtracting the biggest possible values from the number. Each subtraction adds the corresponding Roman symbol to the result:

for (let i = 0; i = values[i]) {
    result += symbols[i];
    num -= values[i];
}

The result is a combination of all the symbols after the subtraction is completed.

Final Implementation

function integerToRoman(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[i]) {
      result += symbols[i];
      num -= values[i];
    }
  }
  return result;
}

That’s all folks!