剑指 Offer 58

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