186.Reverse Words in a String II

class Solution {
public:
    void reverseWords(vector<char>& str) {
        reverse(str.begin(), str.end());
        for (int i = 0, j = 0; i < str.size(); i = j + 1) {
            for (j = i; j < str.size(); ++j) {
                if (str[j] == ' ') break;
            }
            reverse(str.begin() + i, str.begin() + j);
        }
    }
};