题解 | #学英语#

这道题思路很简单，就是需要注意的细节太多。

import java.util.*;
import java.lang.*;

// 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
            long a = in.nextLong();
            String[] sa = String.format("%,d", a).split(",");//使用格式化函数将输入按逗号分隔
            int sal = sa.length;
            String out = "";

            //对每个部分转化处理去掉前缀为0的部分，00X->X,0XX->XX,000->0
            for(int i=0;i<sal;i++){
                sa[i] = String.valueOf(Integer.parseInt(sa[i]));
            }
            //对逗号中间的部分分别做处理，创建treatHundred用于处理三位以下的读法
            Main m = new Main();
            if (sal == 3) {
                out = m.treatHundred(sa[0])+" million "+m.treatHundred(sa[1])+" thousand "+m.treatHundred(sa[2]);
            } else if (sal == 2) {
                out = m.treatHundred(sa[0])+" thousand "+m.treatHundred(sa[1]);
            }else if(sal==1){
                out = m.treatHundred(sa[0]);
            }
            //去掉多余的空格后输出
            out = out.replaceAll("  "," ");
            System.out.println(out.trim());

        }
    }
    //处理三位数字的读法
    public String treatHundred(String s) {
        String[] dict = {"", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"};
        String[] dict1 = {"", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"};
        String[] dict2 = {"", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"};
        String out="";
        switch (s.length()) {
            case 1:
                out = dict[Integer.parseInt(s)];
                break;
            case 2:
                int x = Integer.parseInt(s) / 10;
                int y = Integer.parseInt(s) % 10;
                if (x == 1 && y!=0) {
                    out = dict1[y];
                } else if (x > 1) {
                    out = dict2[x] + " " + dict[y];
                }else if(s.equals("10")){
                    out = "ten";
                }
                break;
            case 3:
                int j = Integer.parseInt(s) / 100; //取百位
                int k = (Integer.parseInt(s) % 100) / 10; //取十位
                int l = (Integer.parseInt(s) % 100) % 10; //取个位
                if (k == 1 && l>0) {
                    out = dict[j] + " hundred and " + dict1[l];
                } else if (k > 1) {
                    out = dict[j] + " hundred and " + dict2[k] + " " + dict[l];
                } else if (k == 0 && l!=0) {
                    out = dict[j] + " hundred and " + dict[l];
                }else if(k==0 && l==0){
                    out = dict[j] + " hundred";
                }else if(k==1 && l==0){
                    out = dict[j] + " hundred and "+"ten";
                }
                break;
        }
        return out;
    }

}