[Leetcode] Reverse Words in a String

 1 class Solution {
 2 public:
 3     void reverse(string &s, int low, int high) {
 4         char tmp;
 5         while(low < high) {
 6             tmp = s[low];
 7             s[low] = s[high];
 8             s[high] = tmp;
 9             low++;
10             high--;
11         }
12     }
13     
14     void removeBlank(string &s) {
15         if (s.length() == 0) {
16             return;
17         }
18         int count = 0;
19         bool flag = false;
20         for (int i = 0; i <= s.length(); ++i) {
21             if (s[i] == ‘ ‘ && !flag) {
22                 count++;
23             } else if (s[i] == ‘ ‘ && flag) {
24                 flag = false;
25                 s[i-count] = s[i];
26             } else if (s[i] != ‘ ‘) {
27                 flag = true;
28                 s[i-count] = s[i];
29             }
30         }
31         int len = s.length() - count;
32         if (s[len-1] == ‘ ‘) {
33             s[len-1] = ‘\0‘;
34             len--;
35         }
36         s.resize(len);
37     }
38 
39     void reverseWords(string &s) {
40         removeBlank(s);
41         reverse(s,0,s.length()-1);
42         int a = 0, b;
43         for (int i=0; i<=s.length();++i){
44             if(s[i]==‘ ‘||s[i]==‘\0‘){
45                 b = i-1;
46                 reverse(s,a,b);
47                 a = i+1;
48             }
49         }
50         return;
51     }
52 };