题解 | #单词倒排#

import java.util.*;

// 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 sc = new Scanner(System.in);
        String str = sc.nextLine();
        char[] charArray = str.toCharArray();
        List<String> list = new ArrayList<>();
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < charArray.length; i++) {
            if ((charArray[i] >= 'A' && charArray[i] <= 'Z') ||
                    charArray[i] >= 'a' && charArray[i] <= 'z') {
                builder.append(charArray[i]);
            } else {
                list.add(builder.toString());
                builder.setLength(0);
            }
        }
        if (builder.length() != 0) {
            list.add(builder.toString());
            builder.setLength(0);
        }
        Collections.reverse(list);
        for (String word : list) {
            builder.append(word + " ");
        }
        builder.deleteCharAt(builder.length() - 1);
        System.out.println(builder.toString());
    }
}