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 in = new Scanner(System.in);
        while (in.hasNext()) {
            String str = in.nextLine();
            char[] chars = str.toCharArray();
            int slow = 0;//慢指针
            StringBuilder sb = new StringBuilder();
            for (char c : chars) {
                if (Character.isLetter(c)) {
                    sb.append(c);
                    slow++;
                } else if (slow > 0 && ' ' != sb.charAt(slow - 1)) {
                    sb.append(" ");
                    slow++;
                }
            }
            String[] ss = sb.toString().split(" ");
            for (int i = ss.length - 1; i >= 0; i--) {
                System.out.print(ss[i] + " ");
            }
        }
    }
}