题解 | #字符串变形#

class Solution {
  public:
    string trans(string s, int n) {
        vector<int> myint;
        for (int i = 0; i < n; i++) {
            if (s[i] >= 'a' && s[i] <= 'z')
                s[i] = toupper(s[i]);
            else if (s[i] >= 'A' && s[i] <= 'Z')
                s[i] = tolower(s[i]);
            else if (s[i] == ' ')
                myint.push_back(i);
        }
        if (myint.size() <= 0)
            return s;
        int i = 0;
        string tmps = "";
        for (auto j : myint) {
            tmps = ' ' + s.substr(i, j - i) + tmps;
            i = j + 1;
        }
        tmps = s.substr(i, n - i) + tmps;
        return tmps;
    }
};