[Leetcode] Reverse Words in a String

Given an input string, reverse the string word by word.
For example,Given s = "the sky is blue ",return "blue is sky the ".
click to show clarification.
Clarification:

What constitutes a word?A sequence of non-space characters constitutes a word.

Could the input string contain leading or trailing spaces?Yes. However, your reversed string should not contain leading or trailing spaces.

How about multiple spaces between two words?Reduce them to a single space in the reversed string.　　

 
あまり言うことはありませんが、スペースに行くのは面倒そうで、一度遍歴すればできます.最後のスペースは特殊に処理することに注意してください.
 

 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 };