template <typename K>
unsigned long hash(K const & key) {
    // TODO
    unsigned long l = 0;
    for ( int i = 0 ; i < key.length; i++ )
      l +=  ( stoi(k.at[i]) * ( i+1) );

    return l;
} // cat // tac -> collision!



// Implement
template <typename K, typename V>
class SimpleHashMap {
public:

    std::mutex m;

    std::vector<std::pair<unsigned long,V> > v;

    bool get(K & key,V & value) {
    auto hashKey = hash(key);
    // TODO <--
    // lock_guard with condition variable return true after write
    {
    std::lock_guard<std::mutex> l(m);

    for ( const auto& it : v )
    {
        if ( it->first == hashKey)
        {
             value = it->second;
             return true;
        }
    }

    }
    //value = "";  // <--
    return false;

    }


    void put(K & key, V & value) {
        // TODO <--
        auto hashKey = hash(key);

        //lock & hold cv
        {
        std::lock_guard<Std::mutex> l(m);

        for ( auto it = v.begin(); it != v.end(); it++ )
        {

            if ( (it->first) == hashKey )
            {

                v.erase(it);
                break;
            }

        }
        v.push_back(std::make_pair(hash(key),value));

        }
        //set cv to true
    }

};