template<typename TKey, typename TValue>

class avltree{
private:
    // called by both clear() and ~avltree() to clear avl tree.
    _clearMemory(){
    }

public:
    // constructors:

    // default
    avltree(){


    }

    //  copy constructor
    avltree(avltree& other){

    }

    int size(){

    }

    int height(){

    }

    // empties tree
    void clear(){
        _clearMemory();
        // TODO: When clear returns, the root should be nullptr and the size 0
    }

    TValue* search(TKey key){
    }

    void insert(){

    }

    /*
        returns path length between 2 keys
        (the length of the minimum path)

    */
    int distance(TKey k1, TKey k2){  // distance
        //int distance = -1;

        if k1 or k2 does not exist in the tree
            return -1

        else if(k1 == k2)
            return 0;
    }

    void inorder(){

    }

    std::vector<TKey> inorder_keys(){
    }

    std::vector<TValue> inorder_values(){
    }

    std::vector<int> inorder_heights(){
    }

    //destructor - TODO: checked using valgrind (week 5 labs)
    virtual ~avltree(){
        _clearMemory();
    }


};