java - 为什么 HashMap 中更高的负载因子会增加查找成本？

Question

来自 HashMap 的 JavaDoc:

As a general rule, the default load factor (.75) offers a good tradeoff between time and space costs. Higher values decrease the space overhead but increase the lookup cost (reflected in most of the operations of the HashMap class, including get and put).

如果我们有更高的值，为什么会增加查找成本？

Answer 1

哈希表的 Load Factor定义为

n/s, the ratio of the number of stored entries n and the size s of the table's array of buckets.

哈希表的高性能在冲突次数较少的情况下得以保持。当负载因子高时，存储相同数量条目所需的哈希桶数量保持较低，从而增加了冲突的可能性。