Words In Phone Number

• Time : O(w)
• Space : O(|w|)

unordered_map<char, char> mp{
    {'a', '2'}, {'b', '2'}, {'c','2'},
    {'d', '3'}, {'e', '3'}, {'f','3'},
    {'g', '4'}, {'h', '4'}, {'i','4'},
    {'j', '5'}, {'k', '5'}, {'l','5'},
    {'m', '6'}, {'n', '6'}, {'o','6'},
    {'p', '7'}, {'q', '7'}, {'r','7'}, {'s','7'},
    {'t', '8'}, {'u', '8'}, {'v','8'},
    {'w', '9'}, {'x', '9'}, {'y','9'}, {'z', '9'}
};
vector<string> wordsInPhoneNumber(string phoneNumber, vector<string> words) {
    vector<string> res;
    for(auto& w: words) {
        string cvt = "";
        for(auto& ch : w) {
            if(isdigit(ch)) cvt.push_back(ch);
            else cvt.push_back(mp[ch]);
        }
        auto pos = phoneNumber.find(cvt);
        if(pos != string::npos) res.push_back(w);
    }
    return res;
}