[LeetCode]-Reverse Words in a String

 1 public class Solution {
 2     private void reverseWord(  char[] arr, int start, int end ){
 3         char temp;
 4         while( start<end ){
 5             temp = arr[start];
 6             arr[start] = arr[end];
 7             arr[end] = temp;
 8             start++;
 9             end--;
10         }
11     }
12     
13     public String reverseWords(String s) {
14         String str = s.trim().replaceAll("\\s+", " ");
15         int len = str.length();
16         char[] arr_str = str.toCharArray();
17         int start = 0;
18         int end = 0;
19         while( start<len ){
20             end = start;
21             while( end<len && arr_str[end]!=‘ ‘ ){
22                 end++;
23             }
24             reverseWord( arr_str, start, end-1 );
25             start = end+1;
26         }
27         reverseWord( arr_str, 0, len-1 );
28         return new String( arr_str );   
29     }
30 }