# 题目: 273. 整数转换英文表示
将非负整数 num 转换为其对应的英文表示。
# 示例1:
输入：num = 123
输出："One Hundred Twenty Three"
# 示例2:
输入：num = 12345
输出："Twelve Thousand Three Hundred Forty Five"
# 迭代
将数字分为三个一组,
# 代码
var numberToWords = function(num) {
const singles = ["", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"];
const teens = ["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"];
const toEnglish = (num) => {
const curr = [];
const hundred = Math.floor(num / 100);
num %= 100;
if (hundred !== 0) {
curr.push(singles[hundred] + " Hundred ");
}
const ten = Math.floor(num / 10);
if (ten >= 2) {
curr.push(tens[ten] + " ");
num %= 10;
}
if (num > 0 && num < 10) {
curr.push(singles[num] + " ");
} else if (num >= 10) {
curr.push(teens[num - 10] + " ");
}
return curr.join('');
}
if (num === 0) {
return "Zero";
}
const sb = [];
for (let i = 3, unit = 1000000000; i >= 0; i--, unit = Math.floor(unit / 1000)) {
const curNum = Math.floor(num / unit);
if (curNum !== 0) {
num -= curNum * unit;
sb.push(toEnglish(curNum) + thousands[i] + " ");
}
}
return sb.join('').trim();
}