题解 | #学英语#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
  const n = Number(await readline());
  const word1 =
    "zero one two three four five six seven eight nine ten eleven twelve thirteen forteen fifteen sixteen seventeen eighteen nineteen".split(
      " "
    );
  const word2 =
    "0 0 twenty thirty forty fifty sixty seventy eighty ninety".split(" ");

  let word = [];

  // 100以内转英文
  function n2w(n) {
    if (n > 0) {
      if (n < 20) {
        word.push(word1[n]);
      } else {
        word.push(word2[Math.floor(n / 10)]);
        if (n % 10 !== 0) {
          word.push(word1[n % 10]);
        }
      }
    }
  }

  // 1000以内转英文
  function hun(n) {
    if (n >= 100) {
      word.push(word1[Math.floor(n / 100)]);
      word.push("hundred");
      if (n % 100 !== 0) {
        word.push("and");
      }
    }
    n2w(n % 100);
  }
  let a = n % 1000, // 个十百位
    b = Math.floor(n / 1000) % 1000, // 个十百千
    c = Math.floor(n / 1000000) % 1000, // 个十百m
    d = Math.floor(n / 1000000000); // 个十百b

  if (d > 0) {
    hun(d);
    word.push("billion");
  }
  if (c) {
    hun(c);
    word.push("million");
  }
  if (b) {
    hun(b);
    word.push("thousand");
  }
  if (a) {
    hun(a);
  }
  console.log(word.join(" "));
})();