[leetcode] Reverse Words in a String

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".

Update (2015-02-12):
For C programmers: Try to solve it in-place in O(1) space.

 

class Solution
{
public:
  void reverseWords(string &s)
  {
    string temp = "", s1 = "";
    for(int i=s.size()-1; i>=0;)
    {
      if(s[i] == ' ' || i == 0) 
      {
        if(i == 0 && s.size()>0 && s[i+1] != ' ' && s[i] != ' ')
          temp = s[i--] + temp;
        else if(i == 0 && s[i] != ' ')
          temp = s[i--];

        while(s[i] == ' ') i--;

        if(s1 == "")
          s1 = temp;
        else
          s1 += " " + temp;

        temp = ""; 
      }
      else if(s[i] != ' ')
        temp = s[i--] + temp;
    }

    s = s1;
  }
};