Dictionary，HashSet的访问时间 [英] Access times for Dictionary, HashSet

问题描述

1. 查找字典中的值


2. 检查是否HashSet有一个值

它是O（1）像C ++ 0x的unordered_map吗？

$ b $是的，当您使用Contains方法或Dictionary的索引器时。

从文档：

字典（TKey，TValue）通用类提供从一组键到一组值的映射。字典中的每个添加都包含一个值及其关联的键。通过使用其键来获取值非常快，接近于O（1），因为Dictionary（Of TKey，TValue）类被实现为哈希表。

http://msdn.microsoft.com/en -us / library / xfhwa508.aspx

What are the access times for:

1. Looking up a value in Dictionary
2. Check whether a HashSet has a value

Is it O(1) like unordered_map of C++0x?

解决方案

Yes, when you use the Contains method or the indexer of the Dictionary.

From the docs:

The Dictionary(Of TKey, TValue) generic class provides a mapping from a set of keys to a set of values. Each addition to the dictionary consists of a value and its associated key. Retrieving a value by using its key is very fast, close to O(1), because the Dictionary(Of TKey, TValue) class is implemented as a hash table.

http://msdn.microsoft.com/en-us/library/xfhwa508.aspx

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