Integer to English Words Hard 0 attempts
LeetCode ↗

Integer to English Words

Hard StringHash Table LeetCode

Spell out a non-negative integer num as English words, exactly as you'd say it out loud. Your solution needs to handle everything from 0 up through 2^31 - 1, following the usual English number-naming pattern of breaking the value into Billion, Million, and Thousand groupings, each of which is itself built from Hundreds, Tens, and Ones.

Input Format
Implement numberToWords(num). Inputs below show JavaScript function arguments; there is no stdin parsing.
Output Format
Return the result described in the statement.

Sample Input and Output

Example 1 ยท Run Sample

Input
num = 123
Output
"One Hundred Twenty Three"

Example 2

Input
num = 0
Output
"Zero"
Constraints
  • 0 <= num <= 2^31 - 1
Test Cases (2)
Case 1
Args: [123] Expected: "One Hundred Twenty Three"
Case 2
Args: [0] Expected: "Zero"
Topics
StringHash Table

Chunk by Thousands

javascript
function numberToWords(num) {
  if (num === 0) return "Zero";
  const ones = ['','One','Two','Three','Four','Five','Six','Seven','Eight','Nine',
    'Ten','Eleven','Twelve','Thirteen','Fourteen','Fifteen','Sixteen','Seventeen','Eighteen','Nineteen'];
  const tens = ['','','Twenty','Thirty','Forty','Fifty','Sixty','Seventy','Eighty','Ninety'];
  const thousands = ['','Thousand','Million','Billion'];
  function helper(n) {
    if (n === 0) return '';
    if (n < 20) return ones[n] + ' ';
    if (n < 100) return tens[Math.floor(n/10)] + ' ' + helper(n%10);
    return ones[Math.floor(n/100)] + ' Hundred ' + helper(n%100);
  }
  let result = '', i = 0;
  while (num > 0) {
    if (num % 1000 !== 0) result = helper(num % 1000) + thousands[i] + ' ' + result;
    num = Math.floor(num / 1000); i++;
  }
  return result.trim();
}

Time: O(1) | Space: O(1)

Saved in this browser only. Private to you.

JavaScript