题解 | #单词倒排#倒着验证，非字母跳过，字母截取

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        String s=sc.nextLine();
        int n=s.length();
        int i=n-1;
        int j=n-1;
        StringBuilder sb=new StringBuilder();
        while(j>=0){
            while(j>=0 && !Character.isLetter(s.charAt(j))){
                j--;
            }
            i=j;
            while(j>=0 && Character.isLetter(s.charAt(j))){
                j--;
            }
            sb.append(s.substring(j+1,i+1)+" ");
        }
        sb.deleteCharAt(sb.length()-1);
        System.out.println(sb.toString());
    }
}