class Solution {
public:
    string decodeMessage(string key, string message) {
        char ch[26] {};
        int len = key.size();
        int flag = 0;
        for (int i = 0; flag < 26 && i < len; i++) {
            if (key[i] == ' ') continue;
            if (ch[key[i]-'a'] == 0) {
                ch[key[i]-'a'] = char(flag + 'a');
                flag++;
            }
        }
        len = message.size();
        string ret;
        for (int i = 0; i < len; i++) {
            if (message[i] == ' ') {
                ret.push_back(' ');
                continue;
            }
            ret.push_back(ch[message[i]-'a']);
        }
        return ret;
    }
};