Question

我正在尝试使用AVL树实现Dictionary ADT，并且遇到findAll（K key）方法的问题。我知道如何使用entries（）方法执行此操作并迭代每个但我需要我的方法为O（logn）所以我需要使用treeSearch（key，position）方法。我的字典看起来像这样：公共课FoodDictionary，V＆gt;实现Dictionary {

/** List in which all the entries are stored. */
private AVLTree<K,V> dictionary;

/** Create a new, empty unordered Dictionary. */
public FoodDictionary() {
    dictionary = new AVLTree<K,V>();
}

/**
 * FOR TESTING PURPOSES ONLY! 
 */
protected AVLTree<K,V> getTree(){
    return dictionary;
}

/**
 * Returns an iterable object of all the entries in the tree
 * @returns the tree, an iterable object
 */
public Iterable<Entry<K, V>> entries() {
    return dictionary;
}

/**
 * Returns the first entry found with the matching
 * key.
 * @param key the key to be found
 * @return the first entry found 
 */
public Entry<K, V> find(K key) {
    return dictionary.find(key).element();
}

/**
 * Returns all of the entries with the given key
 * 
 * @param key the key to be found 
 * @return an iterable object containing all the 
 * entries found with the given key
 */
public Iterable<Entry<K, V>> findAll(K key) {
    PLSequence<Entry<K,V>> list = new PLSequence<Entry<K,V>>();
    for(Entry<K,V> entry : entries()){
        if(entry.getKey().equals(key)){
            list.addLast(entry);
        }
    }
    return list;
}


/**
 * Returns the size of the dictionary
 * @return the size of the dictionary
 */
@Override
public int size() {
    return dictionary.size();
}

/**
 * Returns whether or not the dictionary 
 * is empty
 * @return true if the dictionary is empty
 *          false if the dictionary is not empty
 */
@Override
public boolean isEmpty() {
    return dictionary.isEmpty();
}

/**
 * Adds an entry to this dictionary
 * @param key they key of the new entry
 * @param value the value of the new entry
 * @return the new entry added to the dictionary
 * @throws InvalidKeyException if the given key was not valid
 */
@Override
public Entry<K, V> insert(K key, V value) throws InvalidKeyException {
    return dictionary.add(key, value);
}

/**
 * Removes an entry from this dictionary
 * @param e the entry to be removed
 * @return the entry removed or null if it was not found
 * @throws InvalidEntryException if the entry input was invalid
 */
@Override
public Entry<K, V> remove(Entry<K, V> e) throws InvalidEntryException {
    return dictionary.remove(e.getKey());
}
}

目前，正如我所说，我的findAll（）使用entries（）来迭代但我需要以某种方式使用treeSearch（）任何人都可以帮我这个实现吗？我没有太多时间来完成它，我完全迷失在想法上。任何帮助表示赞赏！

使用AVL Tree findAll（）方法实现字典

0 个答案: