题解 | #学英语#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        // while (in.hasNextInt()) { // 注意 while 处理多个 case
        //     int a = in.nextInt();
        //     int b = in.nextInt();
        //     System.out.println(a + b);
        // }
        long n = in.nextLong();
        String[] strs = {"one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"};
        String num = "";

        int count = 0;
        while (n != 0) {
            String str = "";
            int t = (int)(n % 1000);
            n /= 1000;

            int hundred = t / 100;
            int ten = t % 100;
            str = getSubStr(t, hundred, ten, strs);
            if (count == 1) {
                str = str + " " + "thousand ";
            } else if (count == 2) {
                str = str + " " + "million ";
            }
            num = str + num;
            count++;
        }
        System.out.print(num);
    }

    private static String getSubStr(int thousand, int hundred, int ten, String[] strs) {
        String str = "";
        if (thousand % 100 == 0) {
            return strs[thousand / 100 - 1] + " " + "hundred ";
        }
        if (ten < 20) {
            str = strs[ten - 1];
        } else if (ten >= 20) {
            if (ten % 10 == 0) {
                str = strs[ten / 10 + 17];
            } else {
                str = strs[ten / 10 + 17] + " " + strs[ten % 10 - 1];
            }
        }

        if (hundred != 0) {
            str = strs[hundred - 1] + " " + "hundred " + "and " + str;
        }
        return str;
    }
}