题解 | #单词倒排#

判断是不是字母: Character.isLetter(ch[i])

import java.util.regex.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String test = sc.nextLine();
        
        char[] ch = test.toCharArray();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < ch.length; i++) {
            if (Character.isLetter(ch[i])) {
                sb.append(ch[i]);
            }else{
                sb.append(" ");
            }
        }
        String[] arr = sb.toString().split(" ");
        for (int i = arr.length - 1; i >= 0; i--) {
            System.out.print(arr[i]+" ");
        }
    }
}