LeetCode-Reverse Words in a String

 1 public class Solution {
 2     public String reverseWords(String s) {
 3         s = s.trim();
 4 
 5         StringBuffer buff = new StringBuffer();
 6         int start = s.length()-1;
 7         while (start>=0){
 8             //Search the next work.
 9             int end = start;
10             while (end>=0 && s.charAt(end)!=‘ ‘) end--;
11             String word = s.substring(end+1,start+1);
12             buff.append(word);
13             if (end>0) buff.append(" ");
14 
15             //skip all the following spaces.
16             while (end>=0 && s.charAt(end)==‘ ‘) end--;
17             start = end;
18         }
19 
20         return buff.toString();
21     }
22 }