灵活运用String.split/replaceAll的正则表达式用法
import java.util.*;
public class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
String input=scan.nextLine();
input=input.replaceAll("[^a-zA-Z]"," ");
String[] outputs=input.split("\\s+");
for(int i=outputs.length-1;i>=0;i--){
System.out.print(outputs[i]+" ");
}
}
}