# LeetCode - 0557. Reverse Words in a String III
### 題目網址：https://leetcode.com/problems/reverse-words-in-a-string-iii/
###### tags: `LeetCode` `Easy` `字串`

/*
    -LeetCode format-
    Problem: 557. Reverse Words in a String III
    Difficulty: Easy
    
    by Inversionpeter
*/



class Solution {
    
    void ReverseWord(string &input, int start, int end) {
        int half = (end + start) >> 1;
        for (int i = start; i < half; ++i)
            swap(input[i], input[end - (i - start) - 1]);
    }
    
public:
    string reverseWords(string s) {
        if (!s.size())
            return "";
        int last = 0;
        for (int i = 0; i != s.size(); ++i)
            if (s[i] == ' ')
                ReverseWord(s, last, i), last = i + 1;
        if (last != s.size())
            ReverseWord(s, last, s.size());
        return s;
    }
};