题解 | #学英语#就硬解吧~

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);
        long m = in.nextLong();

        long p = m % 1000;

        String str = getStr(p);
        str = str == null ? "" : str;

        long q = m / 1000 % 1000;
        String s = getStr(q);
        if (s != null) {
            str = s + " thousand " + str;
        }

        long w = m / 1000000 % 1000;
        s = getStr(w);
        if (s != null) {
            str = s + " million " + str;
        }


        System.out.println(str);
    }

    private static String getStr(long p) {
        if (p != 0) {
            String str = "";
            long z = p % 100;
            if (z < 20 && z > 9) { // 10 - 19
                str = str + getNum((int) z);
            } else {
                str = getTenDigit((int) (z / 10));
                String individualBit = getIndividualBit((int) (z % 10));
                if (individualBit != null && str != null) {
                    str = str + " " + individualBit;
                } else if (individualBit != null) {
                    str = individualBit;
                }
            }

            long x = p / 100;
            String ss = "";
            if (x != 0) {
                String individualBit = getIndividualBit((int) x);
                ss = individualBit + " hundred";
            }

            if (z != 0 && x != 0) {
                str = ss + " and " + str;
            } else if (x != 0) {
                str = ss;
            }
            return str;
        }
        return null;
    }

    static String getIndividualBit(int c) {
        switch (c) {
            case 1:
                return "one";
            case 2:
                return "two";
            case 3:
                return "three";
            case 4:
                return "four";
            case 5:
                return "five";
            case 6:
                return "six";
            case 7:
                return "seven";
            case 8:
                return "eight";
            case 9:
                return "nine";
            default:
                return null;
        }
    }

    static String getTenDigit(int c) {
        switch (c) {
            case 2:
                return "twenty";
            case 3:
                return "thirty";
            case 4:
                return "forty";
            case 5:
                return "fifty";
            case 6:
                return "sixty";
            case 7:
                return "seventy";
            case 8:
                return "eighty";
            case 9:
                return "ninety";
            default:
                return null;
        }
    }

    static String getNum(int num) {
        switch (num) {
            case 10:
                return "ten";
            case 11:
                return "eleven";
            case 12:
                return "twelve";
            case 13:
                return "thirteen";
            case 14:
                return "fourteen";
            case 15:
                return "fifteen";
            case 16:
                return "sixteen";
            case 17:
                return "seventeen";
            case 18:
                return "eighteen";
            case 19:
                return "nineteen";
        }
        return null;
    }
}