题解 | #单词倒排#

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 scanner = new Scanner(System.in);
        scanner.useDelimiter("\n");

        String s1 = null;
        if (scanner.hasNext()) {
            s1 = scanner.next();
        }
        if (s1 == null || s1.length()==0) return;
        StringBuilder builder = new StringBuilder();
        StringBuilder builder2 = new StringBuilder();


        for (int i = s1.length()-1;; i--) {
             if (i<0) {
                builder.append(builder2.reverse());
                break;
            }
             if ((s1.charAt(i) >= 65 && s1.charAt(i) <= 95) || (s1.charAt(i) >= 97 && s1.charAt(i) <= 122)) {
                 builder2.append(s1.charAt(i));
             } else if (builder2.length()!=0){
                 builder.append(builder2.reverse());
                 builder.append(" ");
                 builder2.delete(0, builder2.length());
             }
        }
        
        System.out.println(builder);
    }
}