Leetcode•Sep 12, 2025
Integer to English Words
Hazrat Ali
Leetcode
Convert a non-negative integer num to its English words representation.
Example 1:
Input: num = 123 Output: "One Hundred Twenty Three"
Example 2:
Input: num = 12345 Output: "Twelve Thousand Three Hundred Forty Five"
Example 3:
Input: num = 1234567 Output: "One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven"
Solution
const LESS_THAN_20 = [
'',
'One',
'Two',
'Three',
'Four',
'Five',
'Six',
'Seven',
'Eight',
'Nine',
'Ten',
'Eleven',
'Twelve',
'Thirteen',
'Fourteen',
'Fifteen',
'Sixteen',
'Seventeen',
'Eighteen',
'Nineteen',
];
const TENS = ['', 'Ten', 'Twenty', 'Thirty', 'Forty', 'Fifty', 'Sixty', 'Seventy', 'Eighty', 'Ninety'];
const THOUSANDS = ['', 'Thousand', 'Million', 'Billion'];
/**
* @param {number} num
* @return {string}
*/
const numberToWords = num => {
if (num === 0) return 'Zero';
let i = 0;
let words = '';
while (num > 0) {
if (num % 1000 !== 0) words = helper(num % 1000) + THOUSANDS[i] + ' ' + words;
num = Math.floor(num / 1000);
i++;
}
return words.trim();
};
const helper = num => {
if (num === 0) return '';
else if (num < 20) return LESS_THAN_20[num] + ' ';
else if (num < 100) return TENS[Math.floor(num / 10)] + ' ' + helper(num % 10);
else return LESS_THAN_20[Math.floor(num / 100)] + ' Hundred ' + helper(num % 100);
};