Hashtable 負載因子Load Factor

 負載因子(load factor)，它用來衡量哈希表的 空/滿 程度，一定程度上也可以體現查詢的效率，計算公式為:

The ratio of the number of elements in the hash table to the table size is
called the load factor. Studies have shown that hash table performance is best
when the load factor is 1.0, or when the table size exactly equals the number
of elements.

public Hashtable(int capacity, float loadFactor);

負載因子 = 總鍵值對數 / 箱子個數