273. Integer to English Words
Description
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"
Constraints:
0 <= num <= 231 - 1
Solutions
Solution 1
Python3
class Solution:
def numberToWords(self, num: int) -> str:
if num == 0:
return 'Zero'
lt20 = [
'',
'One',
'Two',
'Three',
'Four',
'Five',
'Six',
'Seven',
'Eight',
'Nine',
'Ten',
'Eleven',
'Twelve',
'Thirteen',
'Fourteen',
'Fifteen',
'Sixteen',
'Seventeen',
'Eighteen',
'Nineteen',
]
tens = [
'',
'Ten',
'Twenty',
'Thirty',
'Forty',
'Fifty',
'Sixty',
'Seventy',
'Eighty',
'Ninety',
]
thousands = ['Billion', 'Million', 'Thousand', '']
def transfer(num):
if num == 0:
return ''
if num < 20:
return lt20[num] + ' '
if num < 100:
return tens[num // 10] + ' ' + transfer(num % 10)
return lt20[num // 100] + ' Hundred ' + transfer(num % 100)
res = []
i, j = 1000000000, 0
while i > 0:
if num // i != 0:
res.append(transfer(num // i))
res.append(thousands[j])
res.append(' ')
num %= i
j += 1
i //= 1000
return ''.join(res).strip()
Java
class Solution {
private String[] lt20 = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen",
"Seventeen", "Eighteen", "Nineteen"};
private String[] tens
= {"", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};
private String[] thousands = {"Billion", "Million", "Thousand", ""};
public String numberToWords(int num) {
if (num == 0) {
return "Zero";
}
StringBuilder sb = new StringBuilder();
for (int i = 1000000000, j = 0; i > 0; i /= 1000, ++j) {
if (num / i == 0) {
continue;
}
sb.append(transfer(num / i)).append(thousands[j]).append(' ');
num %= i;
}
return sb.toString().trim();
}
private String transfer(int num) {
if (num == 0) {
return "";
}
if (num < 20) {
return lt20[num] + " ";
}
if (num < 100) {
return tens[num / 10] + " " + transfer(num % 10);
}
return lt20[num / 100] + " Hundred " + transfer(num % 100);
}
}
C++
class Solution {
public:
vector<string> lt20 = {
"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen",
"Sixteen", "Seventeen", "Eighteen", "Nineteen"};
vector<string> tens = {
"", "Ten", "Twenty", "Thirty", "Forty", "Fifty",
"Sixty", "Seventy", "Eighty", "Ninety"};
vector<string> thousands = {"Billion", "Million", "Thousand", ""};
string numberToWords(int num) {
if (num == 0) {
return "Zero";
}
string res;
for (int i = 1000000000, j = 0; i > 0; i /= 1000, ++j) {
int cur = num / i;
if (cur == 0) {
continue;
}
if (!res.empty()) {
res += ' ';
}
res += transfer(cur);
if (!thousands[j].empty()) {
res += ' ';
res += thousands[j];
}
num %= i;
}
return res;
}
private:
string transfer(int num) {
if (num == 0) {
return "";
}
if (num < 20) {
return lt20[num];
}
if (num < 100) {
if (num % 10 == 0) {
return tens[num / 10];
}
return tens[num / 10] + " " + transfer(num % 10);
}
if (num % 100 == 0) {
return lt20[num / 100] + " Hundred";
}
return lt20[num / 100] + " Hundred " + transfer(num % 100);
}
};
Go
func numberToWords(num int) string {
if num == 0 {
return "Zero"
}
lt20 := []string{
"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen",
"Sixteen", "Seventeen", "Eighteen", "Nineteen",
}
tens := []string{
"", "Ten", "Twenty", "Thirty", "Forty", "Fifty",
"Sixty", "Seventy", "Eighty", "Ninety",
}
thousands := []string{"Billion", "Million", "Thousand", ""}
var transfer func(int) string
transfer = func(num int) string {
if num == 0 {
return ""
}
if num < 20 {
return lt20[num]
}
if num < 100 {
if num%10 == 0 {
return tens[num/10]
}
return tens[num/10] + " " + transfer(num%10)
}
if num%100 == 0 {
return lt20[num/100] + " Hundred"
}
return lt20[num/100] + " Hundred " + transfer(num%100)
}
res := ""
for i, j := 1000000000, 0; i > 0; i, j = i/1000, j+1 {
cur := num / i
if cur == 0 {
continue
}
if res != "" {
res += " "
}
res += transfer(cur)
if thousands[j] != "" {
res += " " + thousands[j]
}
num %= i
}
return res
}
TypeScript
function numberToWords(num: number): string {
if (num === 0) {
return 'Zero';
}
const lt20 = [
'',
'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 = ['Billion', 'Million', 'Thousand', ''];
const transfer = (n: number): string => {
if (n === 0) {
return '';
}
if (n < 20) {
return lt20[n];
}
if (n < 100) {
if (n % 10 === 0) {
return tens[Math.floor(n / 10)];
}
return tens[Math.floor(n / 10)] + ' ' + transfer(n % 10);
}
if (n % 100 === 0) {
return lt20[Math.floor(n / 100)] + ' Hundred';
}
return lt20[Math.floor(n / 100)] + ' Hundred ' + transfer(n % 100);
};
let res = '';
for (let i = 1_000_000_000, j = 0; i > 0; i = Math.floor(i / 1000), ++j) {
const cur = Math.floor(num / i);
if (cur === 0) {
continue;
}
if (res !== '') {
res += ' ';
}
res += transfer(cur);
if (thousands[j] !== '') {
res += ' ' + thousands[j];
}
num %= i;
}
return res;
}
JavaScript
/**
* @param {number} num
* @return {string}
*/
var numberToWords = function (num) {
if (num === 0) {
return 'Zero';
}
const lt20 = [
'',
'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 = ['Billion', 'Million', 'Thousand', ''];
const transfer = n => {
if (n === 0) {
return '';
}
if (n < 20) {
return lt20[n];
}
if (n < 100) {
if (n % 10 === 0) {
return tens[Math.floor(n / 10)];
}
return tens[Math.floor(n / 10)] + ' ' + transfer(n % 10);
}
if (n % 100 === 0) {
return lt20[Math.floor(n / 100)] + ' Hundred';
}
return lt20[Math.floor(n / 100)] + ' Hundred ' + transfer(n % 100);
};
let res = '';
for (let i = 1_000_000_000, j = 0; i > 0; i = Math.floor(i / 1000), ++j) {
const cur = Math.floor(num / i);
if (cur === 0) {
continue;
}
if (res !== '') {
res += ' ';
}
res += transfer(cur);
if (thousands[j] !== '') {
res += ' ' + thousands[j];
}
num %= i;
}
return res;
};
C#
public class Solution {
private readonly string[] lt20 = {
"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen",
"Sixteen", "Seventeen", "Eighteen", "Nineteen"
};
private readonly string[] tens = {
"", "Ten", "Twenty", "Thirty", "Forty", "Fifty",
"Sixty", "Seventy", "Eighty", "Ninety"
};
private readonly string[] thousands = { "Billion", "Million", "Thousand", "" };
public string NumberToWords(int num) {
if (num == 0) {
return "Zero";
}
string res = "";
for (int i = 1000000000, j = 0; i > 0; i /= 1000, ++j) {
int cur = num / i;
if (cur == 0) {
continue;
}
if (res.Length > 0) {
res += " ";
}
res += Transfer(cur);
if (thousands[j].Length > 0) {
res += " " + thousands[j];
}
num %= i;
}
return res;
}
private string Transfer(int num) {
if (num == 0) {
return "";
}
if (num < 20) {
return lt20[num];
}
if (num < 100) {
if (num % 10 == 0) {
return tens[num / 10];
}
return tens[num / 10] + " " + Transfer(num % 10);
}
if (num % 100 == 0) {
return lt20[num / 100] + " Hundred";
}
return lt20[num / 100] + " Hundred " + Transfer(num % 100);
}
}