151. 翻转字符串里的单词

输入: "the sky is blue",
输出: "blue is sky the".

public class Solution {
    public String reverseWords(String s) {
        StringBuilder sb = new StringBuilder();
        String[] tmp = s.split(" ", -1);
        for (int i = tmp.length - 1; i >= 0; i--) {
            if (!"".equals(tmp[i])) {
                sb.append(tmp[i]).append(" ");
            }
        }
        if (sb.length() != 0) {
            return sb.deleteCharAt(sb.length() - 1).toString();
        } else {
            return sb.toString();
        }
    }
}