具有合并散列的散列表

Question

我试图弄清楚如何将使用二次探测实现的哈希表类的添加方法转换为使用合并哈希的冲突解决方法。我知道它与链表有关，但是因为我是哈希表的新手，我不知道从哪里开始。

这里是有问题的add方法，

public boolean add(AnyType x) {
    int currentPos = findPos(x);
    if (isActive(array, currentPos))
        return false;
    if (array[currentPos] == null)
        occupied++;
    array[currentPos] = new HashEntry(x, true);
    currentSize++;
    modCount++;
    if (occupied > array.length / 2)
        rehash();
    return true;
}

如果有人能告诉我如何将此方法转换为使用合并散列，我将不胜感激。

Answer 1

所以，在我遵循维基百科指南和代码here 之后，我将那里的代码修改为以下内容。我用 cmets 解释每个部分。

public boolean add(AnyType x) {
    // Finds the place that you want to insert into your table.
    // I believe the function contains the hash mapping
    int currentPos = findPos(x);
    // if the place is empty, you will insert your hash in there
    if (array[currentPos] == null) {
        array[currentPos] = new HashEntry(x, true);
    } else {
        // The place has been occupied (collision occured), so we will 
        // add it as a second item like a link list.
        // But, we do not want to allocate a new space and we use the 
        // empty spaces we have in our hash table instead.
        // That is the differece between coalesced hash and speparate chaining

        // the indexes are from 0 to HASH_TABLE_SIZE -1
        int cursor = HASH_TABLE_SIZE - 1; 
        /* Find the first empty bucket for the new entry */
        while ( cursor >= 0 && array[cursor] != NULL )
            --cursor;

        /* The table is full, terminate unsuccessfully */
        if ( cursor == -1 )
          return false;

        // Initial your new value in an empty bucket we found in the table
        array[cursor] = new HashEntry(x, true);

        /* Find the last node in the chain and point to it */
        // Here we need to find the tail of the link list in our hash table
        // We do not want to miss the link list that we made from the past,
        // therefore, we need to do the following
        struct node* it = array[currentPos];
        while ( it->next != NULL )
          it = it->next;
        // Now we assign the 
        it->next = array[cursor];       
    }
    return true;
}

希望对你有帮助。